* [PATCH v7 00/29] Fair(er) DRM scheduler
@ 2026-03-06 16:34 Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 01/29] drm/sched: Disallow initializing entities with no schedulers Tvrtko Ursulin
` (29 more replies)
0 siblings, 30 replies; 32+ messages in thread
From: Tvrtko Ursulin @ 2026-03-06 16:34 UTC (permalink / raw)
To: amd-gfx, dri-devel
Cc: kernel-dev, intel-xe, Danilo Krummrich, Philipp Stanner,
Tvrtko Ursulin, Christian König, Leo Liu, Lucas Stach,
Matthew Brost, Pierre-Eric Pelloux-Prayer, Michel Dänzer
[disclaimer]
Please note that as this series includes patches which touch a good number of
drivers, I did not copy everyone on everything. Assumption is people are
subscribed to dri-devel and for context can look at the whole series there.
[/disclaimer]
As a summary, the new scheduling algorithm is insipired by the original Linux
CFS and so far no scheduling regressions have been found relative to FIFO.
There are improvements in fairness and scheduling of interactive clients when
running in parallel with a heavy GPU load (for example Pierre-Eric has one
viewperf medical test which shows a nice improvement with amdgpu).
On the high level main advantages of the series are:
1. Scheduling quality - schedules better than FIFO, solves priority starvation.
2. Code simplification - no more multiple run queues and multiple algorithms.
3. Virtual GPU time based scheduling enables relatively simple addition
of a scheduling cgroup controller in the future.
There is a little bit more detailed write up on the motivation and results in
the form of a blog post which may be easier to read:
https://blogs.igalia.com/tursulin/fair-er-drm-gpu-scheduler/
First patches add some unit tests which allow for easy evaluation of scheduling
behaviour against different client submission patterns. From there onwards it is
hopefully a natural progression of cleanups, enablers, adding the fair policy,
and finally removing FIFO and RR and simplifying the code base due no more need
for multiple run queues.
Series is structured in a way where we could apply the first 12 patches (up to
and including "drm/sched: Switch default policy to fair") in one kernel release
and then follow up with the rest of the cleanups after a release or two if
things will be looking fine. Until the remainder of the series would be merged
it would be easy to flip the default algorithm back.
Onto the performance evaluation. As a headline result I have tested three
simultaneous clients on the Steam Deck:
One instance of a deferredmultisampling Vulkan demo running with low priority,
one normal priority instance of the same demo, and the Unigine Heaven benchmark.
With the FIFO scheduler we can see that the low priority client is completely
starved and the GPU time distribution between the other two clients is uneven:
https://people.igalia.com/tursulin/drm-sched-fair/fifo-starvation.png
Switching to the fair scheduler, GPU time distribution is almost equal and the
low priority client does get a small share of the GPU:
https://people.igalia.com/tursulin/drm-sched-fair/fair-no-starvation.png
Moving onto the synthetic submission patterns, they are about two simultaneous
clients which broadly cover the following categories:
* Deep queue clients
* Hogs versus interactive
* Priority handling
Lets look at the results:
1. Two normal priority deep queue clients.
These ones submit one second worth of 8ms jobs. As fast as they can, no
dependencies etc. There is no difference in runtime between FIFO and fair but
the latter allows both clients to progress with work more evenly:
https://people.igalia.com/tursulin/drm-sched-fair/normal-normal.png
(X axis is time, Y is submitted queue-depth, hence lowering of qd corresponds
with work progress for both clients, tested with both schedulers separately.)
Round-robin is the same as fair here.
2. Same two clients but one is now low priority.
https://people.igalia.com/tursulin/drm-sched-fair/normal-low.png
Normal priority client is a solid line, low priority dotted. We can see how FIFO
completely starves the low priority client until the normal priority is fully
done. Only then the low priority client gets any GPU time.
In constrast, fair scheduler allows some GPU time to the low priority client.
Here round-robin flavours are the same as FIFO (same starvation issue).
3. Same clients but now high versus normal priority.
Similar behaviour as in the previous one with normal a bit less de-prioritised
relative to high, than low was against normal.
https://people.igalia.com/tursulin/drm-sched-fair/high-normal.png
And again round-robin flavours are the same as FIFO.
4. Heavy load vs interactive client.
Heavy client emits a 75% GPU load in the format of 3x 2.5ms jobs followed by a
2.5ms wait. Interactive client emits a 10% GPU load in the format of 1x 1ms job
followed by a 9ms wait.
This simulates an interactive graphical client used on top of a relatively heavy
background load but no GPU oversubscription.
Graphs show the interactive client only and from now on, instead of looking at
the client's queue depth, we look at its "fps".
https://people.igalia.com/tursulin/drm-sched-fair/251008/4-heavy-vs-interactive.png
Here round-robin and round-robin rewritten on top of FIFO are best, with the
fair algorithm being very close. FIFO is clearly the worst.
5. An even heavier load vs interactive client.
This one is oversubscribing the GPU by submitting 4x 50ms jobs and waiting for
only one microsecond before repeating the cycle. Interactive client is the same
10% as above.
https://people.igalia.com/tursulin/drm-sched-fair/251008/4-very-heavy-vs-interactive.png
Here FIFO is even worse and fair is again almost as good as the two round-robin
flavours.
6. Low priority GPU hog versus heavy-interactive.
Low priority client: 3x 2.5ms jobs client followed by a 0.5ms wait.
Interactive client: 1x 0.5ms job followed by a 10ms wait.
https://people.igalia.com/tursulin/drm-sched-fair/251008/4-low-hog-vs-interactive.png
All schedulers appear to handle this almost equally well but FIFO could still be
the last while fair has a slight lead.
As before, I am looking for feedback, ideas for what other kinds of submission
scenarios to test, testing on different GPUs and of course reviews.
v2:
* Fixed many rebase errors.
* Added some new patches.
* Dropped single shot dependecy handling.
v3:
* Added scheduling quality unit tests.
* Refined a tiny bit by adding some fairness.
* Dropped a few patches for now.
v4:
* Replaced deadline with fair!
* Refined scheduling quality unit tests.
* Pulled one cleanup patch earlier.
* Fixed "drm/sched: Avoid double re-lock on the job free path".
v5:
* Rebase on top of latest upstream DRM scheduler changes.
* Kerneldoc fixup.
* Improve commit message justification for one patch. (Philipp)
* Add comment in drm_sched_alloc_wq. (Christian)
v6:
* Rebase for "drm/sched: De-clutter drm_sched_init" getting merged.
* Avoid NULL rq dereference from a bad rebase. (Maira)
* Added some kerneldoc throughout. (Maira)
* Removed some lockdep annotations not belonging to one patch. (Maira)
* Use dma_fence_is_signaled in "drm/sched: Avoid double re-lock on the job free path". (Maira, Philipp)
v7:
* Rebase for some prep patches getting merged.
* Dropped submit all ready jobs patch.
* Fixed 64-bit division in unit tests.
* Fixed some more rebase and patch re-ordering mistakes.
* Preserve entity RR order when re-entering the queue.
* Fine tuned the queue re-enter logic for better behaviour with interactive
clients.
* Removed some static inlines.
* Added more kerneldoc.
* Done some benchmarks in the round-robin scheduling modes.
v8:
* Rebased for upstream changes.
* Added assert for reverse numerical order of DRM_SCHED_PRIORITY enums.
* Fixed head of rq priority updates.
*** RFC -> PATCH change log version reset. ***
v9 / v1:
* RFC -> PATCH for the series as agreed during the XDC.
* Updated interactive benchmark graphs.
* Improved handling of interactive clients by replacing the random noise on tie
approach with the average job duration statistics.
* Document in code why we track entity GPU stats in a reference counted structures.
* Document the new structure fields added by the fair policy.
* Undo some tab vs spaces damage.
* More accurate wording in the fair policy commit message.
* Default to fair policy in a separate patch.
* Renamed drm_sched_rq_select_entity to drm_sched_select_entity and make it only take sched.
* Fixed kerneldoc after removing scheduling policies and renaming the rq.
* Reversed arguments of drm_sched_rq_init and cleanup callers. (New patch)
* Removed unused num_rqs from struct drm_sched_args. (New patches)
* Unit tests:
* Added wait duration comments.
* Data structure comments.
* Better name for a local variable.
* Added comment to the short job duration assert.
* Added comment for cond_resched().
* Tweaked some comments
* Added client_done() helper and documented the READ_ONCE.
* Clarified cycles per second calculation.
v2:
* Dropped the sched_rq_init() argument re-order patch.
* Pulled run queue management consolidation patches to start of the series.
* Drm_sched_rq_get_rr_ts() renamed to drm_sched_rq_next_rr_ts().
* Added DRM_SCHED_PRIORITY_INVALID local define.
* Added locking around the ktime_t vruntime read.
* Expanded comment relating to the unlocked entity->priority read.
* Expanded comment relating to the unlocked scheduler average job duration read.
* Various kerneldoc tweaks.
* Undo some tab vs spaces damage harder.
* Undo one empty line rebase damage.
* Reworded commit message for the FIFO and RR removal patch.
* Various commit message spelling, grammar and typo fixes.
* Unit tests:
* Various style changes.
* More descriptive test names.
* Print legend for measured metrics.
* Check for memory allocation failures.
v3:
* Marked fair policy as default in the correct patch.
* Further improved comment in drm_sched_rq_update_prio().
* Moved DRM_SCHED_PRIORITY_INVALID to gpu_scheduler.h.
* Added description of the GPU time to vruntime scaling factors.
* Recorded more collected acks.
v4:
* Rebased, collect ackes and r-b-s receives so far.
* New patch in the series for handling the new ethosu accel driver.
* Bump lower priorities lower down in the run queue when they re-join, in order
to penalize them a bit more than simply making them second in the line to
run as it was in v3.
v5:
* Rebased, collect ackes and r-b-s received so far.
* Fix lost return statement introduced in v2 refactoring.
* Use virtual runtime based on average job durations when placing the re-
joining lower priority entity in the run-queue.
v6:
* Renamed drm_sched_entity_stats_alloc to drm_sched_entity_stats_new.
* Moved drm_sched_entity_stats_job_add_gpu_time to sched_entity.c.
* Improved kerneldoc for struct drm_sched_entity_stats.
* Explained GPU accounting placement in the respective commit text.
* Removed duplicated sched list assignment int the embedding the run-queue
patch.
v7:
* Rebased to catchup with upstream changes.
* Dropped the two amdgpu dependencies from the series - they have been merged
and have propagated to drm-next and drm-tip.
* Applied acks/reviews received since v6.
Cc: Christian König <christian.koenig@amd.com>
Cc: Danilo Krummrich <dakr@kernel.org>
CC: Leo Liu <Leo.Liu@amd.com>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Philipp Stanner <phasta@kernel.org>
Cc: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Cc: Michel Dänzer <michel.daenzer@mailbox.org>
Tvrtko Ursulin (29):
drm/sched: Disallow initializing entities with no schedulers
drm/sched: Consolidate entity run queue management
drm/sched: Move run queue related code into a separate file
drm/sched: Add some scheduling quality unit tests
drm/sched: Add some more scheduling quality unit tests
drm/sched: Implement RR via FIFO
drm/sched: Free all finished jobs at once
drm/sched: Account entity GPU time
drm/sched: Remove idle entity from tree
drm/sched: Add fair scheduling policy
drm/sched: Favour interactive clients slightly
drm/sched: Switch default policy to fair
drm/sched: Remove FIFO and RR and simplify to a single run queue
drm/sched: Embed run queue singleton into the scheduler
accel/amdxdna: Remove drm_sched_init_args->num_rqs usage
accel/rocket: Remove drm_sched_init_args->num_rqs usage
accel/ethosu: Remove drm_sched_init_args->num_rqs usage
drm/amdgpu: Remove drm_sched_init_args->num_rqs usage
drm/etnaviv: Remove drm_sched_init_args->num_rqs usage
drm/imagination: Remove drm_sched_init_args->num_rqs usage
drm/lima: Remove drm_sched_init_args->num_rqs usage
drm/msm: Remove drm_sched_init_args->num_rqs usage
drm/nouveau: Remove drm_sched_init_args->num_rqs usage
drm/panfrost: Remove drm_sched_init_args->num_rqs usage
drm/panthor: Remove drm_sched_init_args->num_rqs usage
drm/sched: Remove drm_sched_init_args->num_rqs usage
drm/v3d: Remove drm_sched_init_args->num_rqs usage
drm/xe: Remove drm_sched_init_args->num_rqs usage
drm/sched: Remove drm_sched_init_args->num_rqs
drivers/accel/amdxdna/aie2_ctx.c | 1 -
drivers/accel/ethosu/ethosu_job.c | 1 -
drivers/accel/rocket/rocket_job.c | 1 -
drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c | 6 +-
drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 1 -
drivers/gpu/drm/amd/amdgpu/amdgpu_job.c | 27 +-
drivers/gpu/drm/amd/amdgpu/amdgpu_job.h | 5 +-
drivers/gpu/drm/amd/amdgpu/amdgpu_trace.h | 8 +-
drivers/gpu/drm/amd/amdgpu/amdgpu_vm_sdma.c | 8 +-
drivers/gpu/drm/amd/amdgpu/amdgpu_xcp.c | 8 +-
drivers/gpu/drm/etnaviv/etnaviv_sched.c | 1 -
drivers/gpu/drm/imagination/pvr_queue.c | 1 -
drivers/gpu/drm/lima/lima_sched.c | 1 -
drivers/gpu/drm/msm/msm_gem_vma.c | 1 -
drivers/gpu/drm/msm/msm_ringbuffer.c | 1 -
drivers/gpu/drm/nouveau/nouveau_sched.c | 1 -
drivers/gpu/drm/panfrost/panfrost_job.c | 1 -
drivers/gpu/drm/panthor/panthor_mmu.c | 1 -
drivers/gpu/drm/panthor/panthor_sched.c | 1 -
drivers/gpu/drm/scheduler/Makefile | 2 +-
drivers/gpu/drm/scheduler/sched_entity.c | 163 ++--
drivers/gpu/drm/scheduler/sched_fence.c | 2 +-
drivers/gpu/drm/scheduler/sched_internal.h | 70 +-
drivers/gpu/drm/scheduler/sched_main.c | 351 +------
drivers/gpu/drm/scheduler/sched_rq.c | 379 ++++++++
drivers/gpu/drm/scheduler/tests/Makefile | 3 +-
.../gpu/drm/scheduler/tests/mock_scheduler.c | 1 -
.../gpu/drm/scheduler/tests/tests_scheduler.c | 884 ++++++++++++++++++
drivers/gpu/drm/v3d/v3d_sched.c | 1 -
drivers/gpu/drm/xe/xe_dep_scheduler.c | 1 -
drivers/gpu/drm/xe/xe_execlist.c | 1 -
drivers/gpu/drm/xe/xe_gpu_scheduler.c | 1 -
include/drm/gpu_scheduler.h | 44 +-
33 files changed, 1497 insertions(+), 481 deletions(-)
create mode 100644 drivers/gpu/drm/scheduler/sched_rq.c
create mode 100644 drivers/gpu/drm/scheduler/tests/tests_scheduler.c
--
2.52.0
^ permalink raw reply [flat|nested] 32+ messages in thread
* [PATCH v7 01/29] drm/sched: Disallow initializing entities with no schedulers
2026-03-06 16:34 [PATCH v7 00/29] Fair(er) DRM scheduler Tvrtko Ursulin
@ 2026-03-06 16:34 ` Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 02/29] drm/sched: Consolidate entity run queue management Tvrtko Ursulin
` (28 subsequent siblings)
29 siblings, 0 replies; 32+ messages in thread
From: Tvrtko Ursulin @ 2026-03-06 16:34 UTC (permalink / raw)
To: amd-gfx, dri-devel
Cc: kernel-dev, intel-xe, Danilo Krummrich, Philipp Stanner,
Tvrtko Ursulin, Christian König, Matthew Brost
Since we have removed the case where amdgpu was initializing entitites
with either no schedulers on the list, or with a single NULL scheduler,
and there appears no other drivers which rely on this, we can simplify the
scheduler by explictly rejecting that early.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Philipp Stanner <phasta@kernel.org>
Reviewed-by: Christian König <christian.koenig@amd.com>
Acked-by: Philipp Stanner <phasta@kernel.org>
---
drivers/gpu/drm/scheduler/sched_entity.c | 13 ++++---------
1 file changed, 4 insertions(+), 9 deletions(-)
diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.c
index fe174a4857be..bb7e5fc47f99 100644
--- a/drivers/gpu/drm/scheduler/sched_entity.c
+++ b/drivers/gpu/drm/scheduler/sched_entity.c
@@ -61,32 +61,27 @@ int drm_sched_entity_init(struct drm_sched_entity *entity,
unsigned int num_sched_list,
atomic_t *guilty)
{
- if (!(entity && sched_list && (num_sched_list == 0 || sched_list[0])))
+ if (!entity || !sched_list || !num_sched_list || !sched_list[0])
return -EINVAL;
memset(entity, 0, sizeof(struct drm_sched_entity));
INIT_LIST_HEAD(&entity->list);
entity->rq = NULL;
entity->guilty = guilty;
- entity->num_sched_list = num_sched_list;
entity->priority = priority;
entity->last_user = current->group_leader;
- /*
- * It's perfectly valid to initialize an entity without having a valid
- * scheduler attached. It's just not valid to use the scheduler before it
- * is initialized itself.
- */
+ entity->num_sched_list = num_sched_list;
entity->sched_list = num_sched_list > 1 ? sched_list : NULL;
RCU_INIT_POINTER(entity->last_scheduled, NULL);
RB_CLEAR_NODE(&entity->rb_tree_node);
- if (num_sched_list && !sched_list[0]->sched_rq) {
+ if (!sched_list[0]->sched_rq) {
/* Since every entry covered by num_sched_list
* should be non-NULL and therefore we warn drivers
* not to do this and to fix their DRM calling order.
*/
pr_warn("%s: called with uninitialized scheduler\n", __func__);
- } else if (num_sched_list) {
+ } else {
/* The "priority" of an entity cannot exceed the number of run-queues of a
* scheduler. Protect against num_rqs being 0, by converting to signed. Choose
* the lowest priority available.
--
2.52.0
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH v7 02/29] drm/sched: Consolidate entity run queue management
2026-03-06 16:34 [PATCH v7 00/29] Fair(er) DRM scheduler Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 01/29] drm/sched: Disallow initializing entities with no schedulers Tvrtko Ursulin
@ 2026-03-06 16:34 ` Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 03/29] drm/sched: Move run queue related code into a separate file Tvrtko Ursulin
` (27 subsequent siblings)
29 siblings, 0 replies; 32+ messages in thread
From: Tvrtko Ursulin @ 2026-03-06 16:34 UTC (permalink / raw)
To: amd-gfx, dri-devel
Cc: kernel-dev, intel-xe, Danilo Krummrich, Philipp Stanner,
Tvrtko Ursulin, Christian König, Matthew Brost
Move the code dealing with entities entering and exiting run queues to
helpers to logically separate it from jobs entering and exiting entities.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Philipp Stanner <phasta@kernel.org>
Acked-by: Danilo Krummrich <dakr@kernel.org>
---
drivers/gpu/drm/scheduler/sched_entity.c | 47 ++-----------
drivers/gpu/drm/scheduler/sched_internal.h | 8 +--
drivers/gpu/drm/scheduler/sched_main.c | 78 ++++++++++++++++++----
3 files changed, 72 insertions(+), 61 deletions(-)
diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.c
index bb7e5fc47f99..768f11510129 100644
--- a/drivers/gpu/drm/scheduler/sched_entity.c
+++ b/drivers/gpu/drm/scheduler/sched_entity.c
@@ -487,26 +487,7 @@ struct drm_sched_job *drm_sched_entity_pop_job(struct drm_sched_entity *entity)
spsc_queue_pop(&entity->job_queue);
- /*
- * Update the entity's location in the min heap according to
- * the timestamp of the next job, if any.
- */
- if (drm_sched_policy == DRM_SCHED_POLICY_FIFO) {
- struct drm_sched_job *next;
-
- next = drm_sched_entity_queue_peek(entity);
- if (next) {
- struct drm_sched_rq *rq;
-
- spin_lock(&entity->lock);
- rq = entity->rq;
- spin_lock(&rq->lock);
- drm_sched_rq_update_fifo_locked(entity, rq,
- next->submit_ts);
- spin_unlock(&rq->lock);
- spin_unlock(&entity->lock);
- }
- }
+ drm_sched_rq_pop_entity(entity);
/* Jobs and entities might have different lifecycles. Since we're
* removing the job from the entities queue, set the jobs entity pointer
@@ -597,30 +578,10 @@ void drm_sched_entity_push_job(struct drm_sched_job *sched_job)
/* first job wakes up scheduler */
if (first) {
struct drm_gpu_scheduler *sched;
- struct drm_sched_rq *rq;
- /* Add the entity to the run queue */
- spin_lock(&entity->lock);
- if (entity->stopped) {
- spin_unlock(&entity->lock);
-
- DRM_ERROR("Trying to push to a killed entity\n");
- return;
- }
-
- rq = entity->rq;
- sched = rq->sched;
-
- spin_lock(&rq->lock);
- drm_sched_rq_add_entity(rq, entity);
-
- if (drm_sched_policy == DRM_SCHED_POLICY_FIFO)
- drm_sched_rq_update_fifo_locked(entity, rq, submit_ts);
-
- spin_unlock(&rq->lock);
- spin_unlock(&entity->lock);
-
- drm_sched_wakeup(sched);
+ sched = drm_sched_rq_add_entity(entity, submit_ts);
+ if (sched)
+ drm_sched_wakeup(sched);
}
}
EXPORT_SYMBOL(drm_sched_entity_push_job);
diff --git a/drivers/gpu/drm/scheduler/sched_internal.h b/drivers/gpu/drm/scheduler/sched_internal.h
index 7ea5a6736f98..8269c5392a82 100644
--- a/drivers/gpu/drm/scheduler/sched_internal.h
+++ b/drivers/gpu/drm/scheduler/sched_internal.h
@@ -12,13 +12,11 @@ extern int drm_sched_policy;
void drm_sched_wakeup(struct drm_gpu_scheduler *sched);
-void drm_sched_rq_add_entity(struct drm_sched_rq *rq,
- struct drm_sched_entity *entity);
+struct drm_gpu_scheduler *
+drm_sched_rq_add_entity(struct drm_sched_entity *entity, ktime_t ts);
void drm_sched_rq_remove_entity(struct drm_sched_rq *rq,
struct drm_sched_entity *entity);
-
-void drm_sched_rq_update_fifo_locked(struct drm_sched_entity *entity,
- struct drm_sched_rq *rq, ktime_t ts);
+void drm_sched_rq_pop_entity(struct drm_sched_entity *entity);
void drm_sched_entity_select_rq(struct drm_sched_entity *entity);
struct drm_sched_job *drm_sched_entity_pop_job(struct drm_sched_entity *entity);
diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
index 21dc82c75c9e..f4aab2915df8 100644
--- a/drivers/gpu/drm/scheduler/sched_main.c
+++ b/drivers/gpu/drm/scheduler/sched_main.c
@@ -151,9 +151,9 @@ static void drm_sched_rq_remove_fifo_locked(struct drm_sched_entity *entity,
}
}
-void drm_sched_rq_update_fifo_locked(struct drm_sched_entity *entity,
- struct drm_sched_rq *rq,
- ktime_t ts)
+static void drm_sched_rq_update_fifo_locked(struct drm_sched_entity *entity,
+ struct drm_sched_rq *rq,
+ ktime_t ts)
{
/*
* Both locks need to be grabbed, one to protect from entity->rq change
@@ -191,23 +191,45 @@ static void drm_sched_rq_init(struct drm_gpu_scheduler *sched,
/**
* drm_sched_rq_add_entity - add an entity
- *
- * @rq: scheduler run queue
* @entity: scheduler entity
+ * @ts: submission timestamp
*
* Adds a scheduler entity to the run queue.
+ *
+ * Return: DRM scheduler selected to handle this entity or NULL if entity has
+ * been stopped and cannot be submitted to.
*/
-void drm_sched_rq_add_entity(struct drm_sched_rq *rq,
- struct drm_sched_entity *entity)
+struct drm_gpu_scheduler *
+drm_sched_rq_add_entity(struct drm_sched_entity *entity, ktime_t ts)
{
- lockdep_assert_held(&entity->lock);
- lockdep_assert_held(&rq->lock);
+ struct drm_gpu_scheduler *sched;
+ struct drm_sched_rq *rq;
- if (!list_empty(&entity->list))
- return;
+ /* Add the entity to the run queue */
+ spin_lock(&entity->lock);
+ if (entity->stopped) {
+ spin_unlock(&entity->lock);
- atomic_inc(rq->sched->score);
- list_add_tail(&entity->list, &rq->entities);
+ DRM_ERROR("Trying to push to a killed entity\n");
+ return NULL;
+ }
+
+ rq = entity->rq;
+ spin_lock(&rq->lock);
+ sched = rq->sched;
+
+ if (list_empty(&entity->list)) {
+ atomic_inc(sched->score);
+ list_add_tail(&entity->list, &rq->entities);
+ }
+
+ if (drm_sched_policy == DRM_SCHED_POLICY_FIFO)
+ drm_sched_rq_update_fifo_locked(entity, rq, ts);
+
+ spin_unlock(&rq->lock);
+ spin_unlock(&entity->lock);
+
+ return sched;
}
/**
@@ -240,6 +262,36 @@ void drm_sched_rq_remove_entity(struct drm_sched_rq *rq,
spin_unlock(&rq->lock);
}
+/**
+ * drm_sched_rq_pop_entity - pops an entity
+ * @entity: scheduler entity
+ *
+ * To be called every time after a job is popped from the entity.
+ */
+void drm_sched_rq_pop_entity(struct drm_sched_entity *entity)
+{
+ /*
+ * Update the entity's location in the min heap according to
+ * the timestamp of the next job, if any.
+ */
+ if (drm_sched_policy == DRM_SCHED_POLICY_FIFO) {
+ struct drm_sched_job *next;
+
+ next = drm_sched_entity_queue_peek(entity);
+ if (next) {
+ struct drm_sched_rq *rq;
+
+ spin_lock(&entity->lock);
+ rq = entity->rq;
+ spin_lock(&rq->lock);
+ drm_sched_rq_update_fifo_locked(entity, rq,
+ next->submit_ts);
+ spin_unlock(&rq->lock);
+ spin_unlock(&entity->lock);
+ }
+ }
+}
+
/**
* drm_sched_rq_select_entity_rr - Select an entity which could provide a job to run
*
--
2.52.0
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH v7 03/29] drm/sched: Move run queue related code into a separate file
2026-03-06 16:34 [PATCH v7 00/29] Fair(er) DRM scheduler Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 01/29] drm/sched: Disallow initializing entities with no schedulers Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 02/29] drm/sched: Consolidate entity run queue management Tvrtko Ursulin
@ 2026-03-06 16:34 ` Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 04/29] drm/sched: Add some scheduling quality unit tests Tvrtko Ursulin
` (26 subsequent siblings)
29 siblings, 0 replies; 32+ messages in thread
From: Tvrtko Ursulin @ 2026-03-06 16:34 UTC (permalink / raw)
To: amd-gfx, dri-devel
Cc: kernel-dev, intel-xe, Danilo Krummrich, Philipp Stanner,
Tvrtko Ursulin, Christian König, Matthew Brost
Lets move all the code dealing with struct drm_sched_rq into a separate
compilation unit. Advantage being sched_main.c is left with a clearer set
of responsibilities.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Philipp Stanner <phasta@kernel.org>
Reviewed-by: Matthew Brost <matthew.brost@intel.com> # v1
Acked-by: Danilo Krummrich <dakr@kernel.org>
---
v2:
* Re-based for moving earlier in the series.
---
drivers/gpu/drm/scheduler/Makefile | 2 +-
drivers/gpu/drm/scheduler/sched_internal.h | 12 +
drivers/gpu/drm/scheduler/sched_main.c | 261 +-------------------
drivers/gpu/drm/scheduler/sched_rq.c | 262 +++++++++++++++++++++
4 files changed, 277 insertions(+), 260 deletions(-)
create mode 100644 drivers/gpu/drm/scheduler/sched_rq.c
diff --git a/drivers/gpu/drm/scheduler/Makefile b/drivers/gpu/drm/scheduler/Makefile
index 6e13e4c63e9d..74e75eff6df5 100644
--- a/drivers/gpu/drm/scheduler/Makefile
+++ b/drivers/gpu/drm/scheduler/Makefile
@@ -20,7 +20,7 @@
# OTHER DEALINGS IN THE SOFTWARE.
#
#
-gpu-sched-y := sched_main.o sched_fence.o sched_entity.o
+gpu-sched-y := sched_main.o sched_fence.o sched_entity.o sched_rq.o
obj-$(CONFIG_DRM_SCHED) += gpu-sched.o
diff --git a/drivers/gpu/drm/scheduler/sched_internal.h b/drivers/gpu/drm/scheduler/sched_internal.h
index 8269c5392a82..aab63a8721d9 100644
--- a/drivers/gpu/drm/scheduler/sched_internal.h
+++ b/drivers/gpu/drm/scheduler/sched_internal.h
@@ -10,14 +10,26 @@ extern int drm_sched_policy;
#define DRM_SCHED_POLICY_RR 0
#define DRM_SCHED_POLICY_FIFO 1
+bool drm_sched_can_queue(struct drm_gpu_scheduler *sched,
+ struct drm_sched_entity *entity);
void drm_sched_wakeup(struct drm_gpu_scheduler *sched);
+void drm_sched_rq_init(struct drm_gpu_scheduler *sched,
+ struct drm_sched_rq *rq);
+
struct drm_gpu_scheduler *
drm_sched_rq_add_entity(struct drm_sched_entity *entity, ktime_t ts);
void drm_sched_rq_remove_entity(struct drm_sched_rq *rq,
struct drm_sched_entity *entity);
void drm_sched_rq_pop_entity(struct drm_sched_entity *entity);
+struct drm_sched_entity *
+drm_sched_rq_select_entity_rr(struct drm_gpu_scheduler *sched,
+ struct drm_sched_rq *rq);
+struct drm_sched_entity *
+drm_sched_rq_select_entity_fifo(struct drm_gpu_scheduler *sched,
+ struct drm_sched_rq *rq);
+
void drm_sched_entity_select_rq(struct drm_sched_entity *entity);
struct drm_sched_job *drm_sched_entity_pop_job(struct drm_sched_entity *entity);
diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
index f4aab2915df8..298509e40d69 100644
--- a/drivers/gpu/drm/scheduler/sched_main.c
+++ b/drivers/gpu/drm/scheduler/sched_main.c
@@ -112,8 +112,8 @@ static u32 drm_sched_available_credits(struct drm_gpu_scheduler *sched)
* Return true if we can push at least one more job from @entity, false
* otherwise.
*/
-static bool drm_sched_can_queue(struct drm_gpu_scheduler *sched,
- struct drm_sched_entity *entity)
+bool drm_sched_can_queue(struct drm_gpu_scheduler *sched,
+ struct drm_sched_entity *entity)
{
struct drm_sched_job *s_job;
@@ -133,263 +133,6 @@ static bool drm_sched_can_queue(struct drm_gpu_scheduler *sched,
return drm_sched_available_credits(sched) >= s_job->credits;
}
-static __always_inline bool drm_sched_entity_compare_before(struct rb_node *a,
- const struct rb_node *b)
-{
- struct drm_sched_entity *ent_a = rb_entry((a), struct drm_sched_entity, rb_tree_node);
- struct drm_sched_entity *ent_b = rb_entry((b), struct drm_sched_entity, rb_tree_node);
-
- return ktime_before(ent_a->oldest_job_waiting, ent_b->oldest_job_waiting);
-}
-
-static void drm_sched_rq_remove_fifo_locked(struct drm_sched_entity *entity,
- struct drm_sched_rq *rq)
-{
- if (!RB_EMPTY_NODE(&entity->rb_tree_node)) {
- rb_erase_cached(&entity->rb_tree_node, &rq->rb_tree_root);
- RB_CLEAR_NODE(&entity->rb_tree_node);
- }
-}
-
-static void drm_sched_rq_update_fifo_locked(struct drm_sched_entity *entity,
- struct drm_sched_rq *rq,
- ktime_t ts)
-{
- /*
- * Both locks need to be grabbed, one to protect from entity->rq change
- * for entity from within concurrent drm_sched_entity_select_rq and the
- * other to update the rb tree structure.
- */
- lockdep_assert_held(&entity->lock);
- lockdep_assert_held(&rq->lock);
-
- drm_sched_rq_remove_fifo_locked(entity, rq);
-
- entity->oldest_job_waiting = ts;
-
- rb_add_cached(&entity->rb_tree_node, &rq->rb_tree_root,
- drm_sched_entity_compare_before);
-}
-
-/**
- * drm_sched_rq_init - initialize a given run queue struct
- *
- * @sched: scheduler instance to associate with this run queue
- * @rq: scheduler run queue
- *
- * Initializes a scheduler runqueue.
- */
-static void drm_sched_rq_init(struct drm_gpu_scheduler *sched,
- struct drm_sched_rq *rq)
-{
- spin_lock_init(&rq->lock);
- INIT_LIST_HEAD(&rq->entities);
- rq->rb_tree_root = RB_ROOT_CACHED;
- rq->current_entity = NULL;
- rq->sched = sched;
-}
-
-/**
- * drm_sched_rq_add_entity - add an entity
- * @entity: scheduler entity
- * @ts: submission timestamp
- *
- * Adds a scheduler entity to the run queue.
- *
- * Return: DRM scheduler selected to handle this entity or NULL if entity has
- * been stopped and cannot be submitted to.
- */
-struct drm_gpu_scheduler *
-drm_sched_rq_add_entity(struct drm_sched_entity *entity, ktime_t ts)
-{
- struct drm_gpu_scheduler *sched;
- struct drm_sched_rq *rq;
-
- /* Add the entity to the run queue */
- spin_lock(&entity->lock);
- if (entity->stopped) {
- spin_unlock(&entity->lock);
-
- DRM_ERROR("Trying to push to a killed entity\n");
- return NULL;
- }
-
- rq = entity->rq;
- spin_lock(&rq->lock);
- sched = rq->sched;
-
- if (list_empty(&entity->list)) {
- atomic_inc(sched->score);
- list_add_tail(&entity->list, &rq->entities);
- }
-
- if (drm_sched_policy == DRM_SCHED_POLICY_FIFO)
- drm_sched_rq_update_fifo_locked(entity, rq, ts);
-
- spin_unlock(&rq->lock);
- spin_unlock(&entity->lock);
-
- return sched;
-}
-
-/**
- * drm_sched_rq_remove_entity - remove an entity
- *
- * @rq: scheduler run queue
- * @entity: scheduler entity
- *
- * Removes a scheduler entity from the run queue.
- */
-void drm_sched_rq_remove_entity(struct drm_sched_rq *rq,
- struct drm_sched_entity *entity)
-{
- lockdep_assert_held(&entity->lock);
-
- if (list_empty(&entity->list))
- return;
-
- spin_lock(&rq->lock);
-
- atomic_dec(rq->sched->score);
- list_del_init(&entity->list);
-
- if (rq->current_entity == entity)
- rq->current_entity = NULL;
-
- if (drm_sched_policy == DRM_SCHED_POLICY_FIFO)
- drm_sched_rq_remove_fifo_locked(entity, rq);
-
- spin_unlock(&rq->lock);
-}
-
-/**
- * drm_sched_rq_pop_entity - pops an entity
- * @entity: scheduler entity
- *
- * To be called every time after a job is popped from the entity.
- */
-void drm_sched_rq_pop_entity(struct drm_sched_entity *entity)
-{
- /*
- * Update the entity's location in the min heap according to
- * the timestamp of the next job, if any.
- */
- if (drm_sched_policy == DRM_SCHED_POLICY_FIFO) {
- struct drm_sched_job *next;
-
- next = drm_sched_entity_queue_peek(entity);
- if (next) {
- struct drm_sched_rq *rq;
-
- spin_lock(&entity->lock);
- rq = entity->rq;
- spin_lock(&rq->lock);
- drm_sched_rq_update_fifo_locked(entity, rq,
- next->submit_ts);
- spin_unlock(&rq->lock);
- spin_unlock(&entity->lock);
- }
- }
-}
-
-/**
- * drm_sched_rq_select_entity_rr - Select an entity which could provide a job to run
- *
- * @sched: the gpu scheduler
- * @rq: scheduler run queue to check.
- *
- * Try to find the next ready entity.
- *
- * Return an entity if one is found; return an error-pointer (!NULL) if an
- * entity was ready, but the scheduler had insufficient credits to accommodate
- * its job; return NULL, if no ready entity was found.
- */
-static struct drm_sched_entity *
-drm_sched_rq_select_entity_rr(struct drm_gpu_scheduler *sched,
- struct drm_sched_rq *rq)
-{
- struct drm_sched_entity *entity;
-
- spin_lock(&rq->lock);
-
- entity = rq->current_entity;
- if (entity) {
- list_for_each_entry_continue(entity, &rq->entities, list) {
- if (drm_sched_entity_is_ready(entity))
- goto found;
- }
- }
-
- list_for_each_entry(entity, &rq->entities, list) {
- if (drm_sched_entity_is_ready(entity))
- goto found;
-
- if (entity == rq->current_entity)
- break;
- }
-
- spin_unlock(&rq->lock);
-
- return NULL;
-
-found:
- if (!drm_sched_can_queue(sched, entity)) {
- /*
- * If scheduler cannot take more jobs signal the caller to not
- * consider lower priority queues.
- */
- entity = ERR_PTR(-ENOSPC);
- } else {
- rq->current_entity = entity;
- reinit_completion(&entity->entity_idle);
- }
-
- spin_unlock(&rq->lock);
-
- return entity;
-}
-
-/**
- * drm_sched_rq_select_entity_fifo - Select an entity which provides a job to run
- *
- * @sched: the gpu scheduler
- * @rq: scheduler run queue to check.
- *
- * Find oldest waiting ready entity.
- *
- * Return an entity if one is found; return an error-pointer (!NULL) if an
- * entity was ready, but the scheduler had insufficient credits to accommodate
- * its job; return NULL, if no ready entity was found.
- */
-static struct drm_sched_entity *
-drm_sched_rq_select_entity_fifo(struct drm_gpu_scheduler *sched,
- struct drm_sched_rq *rq)
-{
- struct rb_node *rb;
-
- spin_lock(&rq->lock);
- for (rb = rb_first_cached(&rq->rb_tree_root); rb; rb = rb_next(rb)) {
- struct drm_sched_entity *entity;
-
- entity = rb_entry(rb, struct drm_sched_entity, rb_tree_node);
- if (drm_sched_entity_is_ready(entity)) {
- /* If we can't queue yet, preserve the current entity in
- * terms of fairness.
- */
- if (!drm_sched_can_queue(sched, entity)) {
- spin_unlock(&rq->lock);
- return ERR_PTR(-ENOSPC);
- }
-
- reinit_completion(&entity->entity_idle);
- break;
- }
- }
- spin_unlock(&rq->lock);
-
- return rb ? rb_entry(rb, struct drm_sched_entity, rb_tree_node) : NULL;
-}
-
/**
* drm_sched_run_job_queue - enqueue run-job work
* @sched: scheduler instance
diff --git a/drivers/gpu/drm/scheduler/sched_rq.c b/drivers/gpu/drm/scheduler/sched_rq.c
new file mode 100644
index 000000000000..cfc18fc7a411
--- /dev/null
+++ b/drivers/gpu/drm/scheduler/sched_rq.c
@@ -0,0 +1,262 @@
+#include <linux/rbtree.h>
+
+#include <drm/drm_print.h>
+#include <drm/gpu_scheduler.h>
+
+#include "sched_internal.h"
+
+static __always_inline bool
+drm_sched_entity_compare_before(struct rb_node *a, const struct rb_node *b)
+{
+ struct drm_sched_entity *ea =
+ rb_entry((a), struct drm_sched_entity, rb_tree_node);
+ struct drm_sched_entity *eb =
+ rb_entry((b), struct drm_sched_entity, rb_tree_node);
+
+ return ktime_before(ea->oldest_job_waiting, eb->oldest_job_waiting);
+}
+
+static void drm_sched_rq_remove_fifo_locked(struct drm_sched_entity *entity,
+ struct drm_sched_rq *rq)
+{
+ if (!RB_EMPTY_NODE(&entity->rb_tree_node)) {
+ rb_erase_cached(&entity->rb_tree_node, &rq->rb_tree_root);
+ RB_CLEAR_NODE(&entity->rb_tree_node);
+ }
+}
+
+static void drm_sched_rq_update_fifo_locked(struct drm_sched_entity *entity,
+ struct drm_sched_rq *rq,
+ ktime_t ts)
+{
+ /*
+ * Both locks need to be grabbed, one to protect from entity->rq change
+ * for entity from within concurrent drm_sched_entity_select_rq and the
+ * other to update the rb tree structure.
+ */
+ lockdep_assert_held(&entity->lock);
+ lockdep_assert_held(&rq->lock);
+
+ drm_sched_rq_remove_fifo_locked(entity, rq);
+
+ entity->oldest_job_waiting = ts;
+
+ rb_add_cached(&entity->rb_tree_node, &rq->rb_tree_root,
+ drm_sched_entity_compare_before);
+}
+
+/**
+ * drm_sched_rq_init - initialize a given run queue struct
+ * @sched: scheduler instance to associate with this run queue
+ * @rq: scheduler run queue
+ *
+ * Initializes a scheduler runqueue.
+ */
+void drm_sched_rq_init(struct drm_gpu_scheduler *sched,
+ struct drm_sched_rq *rq)
+{
+ spin_lock_init(&rq->lock);
+ INIT_LIST_HEAD(&rq->entities);
+ rq->rb_tree_root = RB_ROOT_CACHED;
+ rq->sched = sched;
+}
+
+/**
+ * drm_sched_rq_add_entity - add an entity
+ * @entity: scheduler entity
+ * @ts: submission timestamp
+ *
+ * Adds a scheduler entity to the run queue.
+ *
+ * Return: DRM scheduler selected to handle this entity or NULL if entity has
+ * been stopped and cannot be submitted to.
+ */
+struct drm_gpu_scheduler *
+drm_sched_rq_add_entity(struct drm_sched_entity *entity, ktime_t ts)
+{
+ struct drm_gpu_scheduler *sched;
+ struct drm_sched_rq *rq;
+
+ /* Add the entity to the run queue */
+ spin_lock(&entity->lock);
+ if (entity->stopped) {
+ spin_unlock(&entity->lock);
+
+ DRM_ERROR("Trying to push to a killed entity\n");
+ return NULL;
+ }
+
+ rq = entity->rq;
+ spin_lock(&rq->lock);
+ sched = rq->sched;
+
+ if (list_empty(&entity->list)) {
+ atomic_inc(sched->score);
+ list_add_tail(&entity->list, &rq->entities);
+ }
+
+ if (drm_sched_policy == DRM_SCHED_POLICY_FIFO)
+ drm_sched_rq_update_fifo_locked(entity, rq, ts);
+
+ spin_unlock(&rq->lock);
+ spin_unlock(&entity->lock);
+
+ return sched;
+}
+
+/**
+ * drm_sched_rq_remove_entity - remove an entity
+ * @rq: scheduler run queue
+ * @entity: scheduler entity
+ *
+ * Removes a scheduler entity from the run queue.
+ */
+void drm_sched_rq_remove_entity(struct drm_sched_rq *rq,
+ struct drm_sched_entity *entity)
+{
+ lockdep_assert_held(&entity->lock);
+
+ if (list_empty(&entity->list))
+ return;
+
+ spin_lock(&rq->lock);
+
+ atomic_dec(rq->sched->score);
+ list_del_init(&entity->list);
+
+ if (rq->current_entity == entity)
+ rq->current_entity = NULL;
+
+ if (drm_sched_policy == DRM_SCHED_POLICY_FIFO)
+ drm_sched_rq_remove_fifo_locked(entity, rq);
+
+ spin_unlock(&rq->lock);
+}
+
+/**
+ * drm_sched_rq_pop_entity - pops an entity
+ * @entity: scheduler entity
+ *
+ * To be called every time after a job is popped from the entity.
+ */
+void drm_sched_rq_pop_entity(struct drm_sched_entity *entity)
+{
+ /*
+ * Update the entity's location in the min heap according to
+ * the timestamp of the next job, if any.
+ */
+ if (drm_sched_policy == DRM_SCHED_POLICY_FIFO) {
+ struct drm_sched_job *next;
+
+ next = drm_sched_entity_queue_peek(entity);
+ if (next) {
+ struct drm_sched_rq *rq;
+
+ spin_lock(&entity->lock);
+ rq = entity->rq;
+ spin_lock(&rq->lock);
+ drm_sched_rq_update_fifo_locked(entity, rq,
+ next->submit_ts);
+ spin_unlock(&rq->lock);
+ spin_unlock(&entity->lock);
+ }
+ }
+}
+
+/**
+ * drm_sched_rq_select_entity_rr - Select an entity which could provide a job to run
+ *
+ * @sched: the gpu scheduler
+ * @rq: scheduler run queue to check.
+ *
+ * Try to find the next ready entity.
+ *
+ * Return an entity if one is found; return an error-pointer (!NULL) if an
+ * entity was ready, but the scheduler had insufficient credits to accommodate
+ * its job; return NULL, if no ready entity was found.
+ */
+struct drm_sched_entity *
+drm_sched_rq_select_entity_rr(struct drm_gpu_scheduler *sched,
+ struct drm_sched_rq *rq)
+{
+ struct drm_sched_entity *entity;
+
+ spin_lock(&rq->lock);
+
+ entity = rq->current_entity;
+ if (entity) {
+ list_for_each_entry_continue(entity, &rq->entities, list) {
+ if (drm_sched_entity_is_ready(entity))
+ goto found;
+ }
+ }
+
+ list_for_each_entry(entity, &rq->entities, list) {
+ if (drm_sched_entity_is_ready(entity))
+ goto found;
+
+ if (entity == rq->current_entity)
+ break;
+ }
+
+ spin_unlock(&rq->lock);
+
+ return NULL;
+
+found:
+ if (!drm_sched_can_queue(sched, entity)) {
+ /*
+ * If scheduler cannot take more jobs signal the caller to not
+ * consider lower priority queues.
+ */
+ entity = ERR_PTR(-ENOSPC);
+ } else {
+ rq->current_entity = entity;
+ reinit_completion(&entity->entity_idle);
+ }
+
+ spin_unlock(&rq->lock);
+
+ return entity;
+}
+
+/**
+ * drm_sched_rq_select_entity_fifo - Select an entity which provides a job to run
+ *
+ * @sched: the gpu scheduler
+ * @rq: scheduler run queue to check.
+ *
+ * Find oldest waiting ready entity.
+ *
+ * Return an entity if one is found; return an error-pointer (!NULL) if an
+ * entity was ready, but the scheduler had insufficient credits to accommodate
+ * its job; return NULL, if no ready entity was found.
+ */
+struct drm_sched_entity *
+drm_sched_rq_select_entity_fifo(struct drm_gpu_scheduler *sched,
+ struct drm_sched_rq *rq)
+{
+ struct rb_node *rb;
+
+ spin_lock(&rq->lock);
+ for (rb = rb_first_cached(&rq->rb_tree_root); rb; rb = rb_next(rb)) {
+ struct drm_sched_entity *entity;
+
+ entity = rb_entry(rb, struct drm_sched_entity, rb_tree_node);
+ if (drm_sched_entity_is_ready(entity)) {
+ /* If we can't queue yet, preserve the current entity in
+ * terms of fairness.
+ */
+ if (!drm_sched_can_queue(sched, entity)) {
+ spin_unlock(&rq->lock);
+ return ERR_PTR(-ENOSPC);
+ }
+
+ reinit_completion(&entity->entity_idle);
+ break;
+ }
+ }
+ spin_unlock(&rq->lock);
+
+ return rb ? rb_entry(rb, struct drm_sched_entity, rb_tree_node) : NULL;
+}
--
2.52.0
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH v7 04/29] drm/sched: Add some scheduling quality unit tests
2026-03-06 16:34 [PATCH v7 00/29] Fair(er) DRM scheduler Tvrtko Ursulin
` (2 preceding siblings ...)
2026-03-06 16:34 ` [PATCH v7 03/29] drm/sched: Move run queue related code into a separate file Tvrtko Ursulin
@ 2026-03-06 16:34 ` Tvrtko Ursulin
2026-03-08 10:10 ` kernel test robot
2026-03-06 16:34 ` [PATCH v7 05/29] drm/sched: Add some more " Tvrtko Ursulin
` (25 subsequent siblings)
29 siblings, 1 reply; 32+ messages in thread
From: Tvrtko Ursulin @ 2026-03-06 16:34 UTC (permalink / raw)
To: amd-gfx, dri-devel
Cc: kernel-dev, intel-xe, Danilo Krummrich, Philipp Stanner,
Tvrtko Ursulin, Christian König, Matthew Brost,
Pierre-Eric Pelloux-Prayer
To make evaluating different scheduling policies easier (no need for
external benchmarks) and perfectly repeatable, lets add some synthetic
workloads built upon mock scheduler unit test infrastructure.
Focus is on two parallel clients (two threads) submitting different job
patterns and logging their progress and some overall metrics. This is
repeated for both scheduler credit limit 1 and 2.
Example test output:
Normal and low:
pct1 cps1 qd1; pct2 cps2 qd2
+ 0ms: 0 0 0; 0 0 0
+ 104ms: 100 1240 112; 100 1240 125
+ 209ms: 100 0 99; 100 0 125
+ 313ms: 100 0 86; 100 0 125
+ 419ms: 100 0 73; 100 0 125
+ 524ms: 100 0 60; 100 0 125
+ 628ms: 100 0 47; 100 0 125
+ 731ms: 100 0 34; 100 0 125
+ 836ms: 100 0 21; 100 0 125
+ 939ms: 100 0 8; 100 0 125
+ 1043ms: ; 100 0 120
+ 1147ms: ; 100 0 107
+ 1252ms: ; 100 0 94
+ 1355ms: ; 100 0 81
+ 1459ms: ; 100 0 68
+ 1563ms: ; 100 0 55
+ 1667ms: ; 100 0 42
+ 1771ms: ; 100 0 29
+ 1875ms: ; 100 0 16
+ 1979ms: ; 100 0 3
0: prio=normal sync=0 elapsed_ms=1015ms (ideal_ms=1000ms) cycle_time(min,avg,max)=134,222,978 us latency_time(min,avg,max)=134,222,978
us
1: prio=low sync=0 elapsed_ms=2009ms (ideal_ms=1000ms) cycle_time(min,avg,max)=134,215,806 us latency_time(min,avg,max)=134,215,806 us
There we have two clients represented in the two respective columns, with
their progress logged roughly every 100 milliseconds. The metrics are:
- pct - Percentage progress of the job submit part
- cps - Cycles per second
- qd - Queue depth - number of submitted unfinished jobs
The cycles per second metric is inherent to the fact that workload
patterns are a data driven cycling sequence of:
- Submit 1..N jobs
- Wait for Nth job to finish (optional)
- Sleep (optional)
- Repeat from start
In this particular example we have a normal priority and a low priority
client both spamming the scheduler with 8ms jobs with no sync and no
sleeping. Hence they build very deep queues and we can see how the low
priority client is completely starved until the normal finishes.
Note that the PCT and CPS metrics are irrelevant for "unsync" clients
since they manage to complete all of their cycles instantaneously.
A different example would be:
Heavy and interactive:
pct1 cps1 qd1; pct2 cps2 qd2
+ 0ms: 0 0 0; 0 0 0
+ 106ms: 5 40 3; 5 40 0
+ 209ms: 9 40 0; 9 40 0
+ 314ms: 14 50 3; 14 50 0
+ 417ms: 18 40 0; 18 40 0
+ 522ms: 23 50 3; 23 50 0
+ 625ms: 27 40 0; 27 40 1
+ 729ms: 32 50 0; 32 50 0
+ 833ms: 36 40 1; 36 40 0
+ 937ms: 40 40 0; 40 40 0
+ 1041ms: 45 50 0; 45 50 0
+ 1146ms: 49 40 1; 49 40 1
+ 1249ms: 54 50 0; 54 50 0
+ 1353ms: 58 40 1; 58 40 0
+ 1457ms: 62 40 0; 62 40 1
+ 1561ms: 67 50 0; 67 50 0
+ 1665ms: 71 40 1; 71 40 0
+ 1772ms: 76 50 0; 76 50 0
+ 1877ms: 80 40 1; 80 40 0
+ 1981ms: 84 40 0; 84 40 0
+ 2085ms: 89 50 0; 89 50 0
+ 2189ms: 93 40 1; 93 40 0
+ 2293ms: 97 40 0; 97 40 1
In this case client one is submitting 3x 2.5ms jobs, waiting for the 3rd
and then sleeping for 2.5ms (in effect causing 75% GPU load, minus the
overheads). Second client is submitting 1ms jobs, waiting for each to
finish and sleeping for 9ms (effective 10% GPU load). Here we can see
the PCT and CPS reflecting real progress.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Philipp Stanner <phasta@kernel.org>
Cc: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Acked-by: Christian König <christian.koenig@amd.com>
Acked-by: Danilo Krummrich <dakr@kernel.org>
---
drivers/gpu/drm/scheduler/tests/Makefile | 3 +-
.../gpu/drm/scheduler/tests/tests_scheduler.c | 696 ++++++++++++++++++
2 files changed, 698 insertions(+), 1 deletion(-)
create mode 100644 drivers/gpu/drm/scheduler/tests/tests_scheduler.c
diff --git a/drivers/gpu/drm/scheduler/tests/Makefile b/drivers/gpu/drm/scheduler/tests/Makefile
index 5bf707bad373..9ec185fbbc15 100644
--- a/drivers/gpu/drm/scheduler/tests/Makefile
+++ b/drivers/gpu/drm/scheduler/tests/Makefile
@@ -2,6 +2,7 @@
drm-sched-tests-y := \
mock_scheduler.o \
- tests_basic.o
+ tests_basic.o \
+ tests_scheduler.o
obj-$(CONFIG_DRM_SCHED_KUNIT_TEST) += drm-sched-tests.o
diff --git a/drivers/gpu/drm/scheduler/tests/tests_scheduler.c b/drivers/gpu/drm/scheduler/tests/tests_scheduler.c
new file mode 100644
index 000000000000..4a02bc447914
--- /dev/null
+++ b/drivers/gpu/drm/scheduler/tests/tests_scheduler.c
@@ -0,0 +1,696 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2025 Valve Corporation */
+
+#include <linux/delay.h>
+#include <linux/kthread.h>
+#include <linux/ktime.h>
+#include <linux/math64.h>
+
+#include "sched_tests.h"
+
+/*
+ * DRM scheduler scheduler tests exercise load balancing decisions ie. entity
+ * selection logic.
+ */
+
+static int drm_sched_scheduler_init(struct kunit *test)
+{
+ struct drm_mock_scheduler *sched;
+
+ sched = drm_mock_sched_new(test, MAX_SCHEDULE_TIMEOUT);
+ sched->base.credit_limit = 1;
+
+ test->priv = sched;
+
+ return 0;
+}
+
+static int drm_sched_scheduler_init2(struct kunit *test)
+{
+ struct drm_mock_scheduler *sched;
+
+ sched = drm_mock_sched_new(test, MAX_SCHEDULE_TIMEOUT);
+ sched->base.credit_limit = 2;
+
+ test->priv = sched;
+
+ return 0;
+}
+
+static void drm_sched_scheduler_exit(struct kunit *test)
+{
+ struct drm_mock_scheduler *sched = test->priv;
+
+ drm_mock_sched_fini(sched);
+}
+
+static void drm_sched_scheduler_queue_overhead(struct kunit *test)
+{
+ struct drm_mock_scheduler *sched = test->priv;
+ struct drm_mock_sched_entity *entity;
+ const unsigned int job_us = 1000;
+ const unsigned int jobs = 1000;
+ const unsigned int total_us = jobs * job_us;
+ struct drm_mock_sched_job *job, *first;
+ ktime_t start, end;
+ bool done;
+ int i;
+
+ /*
+ * Deep queue job at a time processing (single credit).
+ *
+ * This measures the overhead of picking and processing a job at a time
+ * by comparing the ideal total "GPU" time of all submitted jobs versus
+ * the time actually taken.
+ */
+
+ KUNIT_ASSERT_EQ(test, sched->base.credit_limit, 1);
+
+ entity = drm_mock_sched_entity_new(test,
+ DRM_SCHED_PRIORITY_NORMAL,
+ sched);
+
+ for (i = 0; i <= jobs; i++) {
+ job = drm_mock_sched_job_new(test, entity);
+ if (i == 0)
+ first = job; /* Extra first job blocks the queue */
+ else
+ drm_mock_sched_job_set_duration_us(job, job_us);
+ drm_mock_sched_job_submit(job);
+ }
+
+ done = drm_mock_sched_job_wait_scheduled(first, HZ);
+ KUNIT_ASSERT_TRUE(test, done);
+
+ start = ktime_get();
+ i = drm_mock_sched_advance(sched, 1); /* Release the queue */
+ KUNIT_ASSERT_EQ(test, i, 1);
+
+ /* Wait with a safe margin to avoid every failing. */
+ done = drm_mock_sched_job_wait_finished(job,
+ usecs_to_jiffies(total_us) * 5);
+ end = ktime_get();
+ KUNIT_ASSERT_TRUE(test, done);
+
+ pr_info("Expected %uus, actual %lldus\n",
+ total_us,
+ ktime_to_us(ktime_sub(end, start)));
+
+ drm_mock_sched_entity_free(entity);
+}
+
+static void drm_sched_scheduler_ping_pong(struct kunit *test)
+{
+ struct drm_mock_sched_job *job, *first, *prev = NULL;
+ struct drm_mock_scheduler *sched = test->priv;
+ struct drm_mock_sched_entity *entity[2];
+ const unsigned int job_us = 1000;
+ const unsigned int jobs = 1000;
+ const unsigned int total_us = jobs * job_us;
+ ktime_t start, end;
+ bool done;
+ int i;
+
+ /*
+ * Two entitites in inter-dependency chain.
+ *
+ * This measures the overhead of picking and processing a job at a time,
+ * where each job depends on the previous one from the diffferent
+ * entity, by comparing the ideal total "GPU" time of all submitted jobs
+ * versus the time actually taken.
+ */
+
+ KUNIT_ASSERT_EQ(test, sched->base.credit_limit, 1);
+
+ for (i = 0; i < ARRAY_SIZE(entity); i++)
+ entity[i] = drm_mock_sched_entity_new(test,
+ DRM_SCHED_PRIORITY_NORMAL,
+ sched);
+
+ for (i = 0; i <= jobs; i++) {
+ job = drm_mock_sched_job_new(test, entity[i & 1]);
+ if (i == 0)
+ first = job; /* Extra first job blocks the queue */
+ else
+ drm_mock_sched_job_set_duration_us(job, job_us);
+ if (prev)
+ drm_sched_job_add_dependency(&job->base,
+ dma_fence_get(&prev->base.s_fence->finished));
+ drm_mock_sched_job_submit(job);
+ prev = job;
+ }
+
+ done = drm_mock_sched_job_wait_scheduled(first, HZ);
+ KUNIT_ASSERT_TRUE(test, done);
+
+ start = ktime_get();
+ i = drm_mock_sched_advance(sched, 1); /* Release the queue */
+ KUNIT_ASSERT_EQ(test, i, 1);
+
+ /* Wait with a safe margin to avoid every failing. */
+ done = drm_mock_sched_job_wait_finished(job,
+ usecs_to_jiffies(total_us) * 5);
+ end = ktime_get();
+ KUNIT_ASSERT_TRUE(test, done);
+
+ pr_info("Expected %uus, actual %lldus\n",
+ total_us,
+ ktime_to_us(ktime_sub(end, start)));
+
+ for (i = 0; i < ARRAY_SIZE(entity); i++)
+ drm_mock_sched_entity_free(entity[i]);
+}
+
+static struct kunit_case drm_sched_scheduler_overhead_tests[] = {
+ KUNIT_CASE_SLOW(drm_sched_scheduler_queue_overhead),
+ KUNIT_CASE_SLOW(drm_sched_scheduler_ping_pong),
+ {}
+};
+
+static struct kunit_suite drm_sched_scheduler_overhead = {
+ .name = "drm_sched_scheduler_overhead_tests",
+ .init = drm_sched_scheduler_init,
+ .exit = drm_sched_scheduler_exit,
+ .test_cases = drm_sched_scheduler_overhead_tests,
+};
+
+/*
+ * struct drm_sched_client_params - describe a workload emitted from a client
+ *
+ * A simulated client will create an entity with a scheduling @priority and emit
+ * jobs in a loop where each iteration will consist of:
+ *
+ * 1. Submit @job_cnt jobs, each with a set duration of @job_us.
+ * 2. If @sync is true wait for last submitted job to finish.
+ * 3. Sleep for @wait_us micro-seconds.
+ * 4. Repeat.
+ */
+struct drm_sched_client_params {
+ enum drm_sched_priority priority;
+ unsigned int job_cnt;
+ unsigned int job_us;
+ bool sync;
+ unsigned int wait_us;
+};
+
+struct drm_sched_test_params {
+ const char *description;
+ struct drm_sched_client_params client[2];
+};
+
+static const struct drm_sched_test_params drm_sched_cases[] = {
+ {
+ .description = "Normal priority and normal priority",
+ .client[0] = {
+ .priority = DRM_SCHED_PRIORITY_NORMAL,
+ .job_cnt = 1,
+ .job_us = 8000,
+ .wait_us = 0,
+ .sync = false,
+ },
+ .client[1] = {
+ .priority = DRM_SCHED_PRIORITY_NORMAL,
+ .job_cnt = 1,
+ .job_us = 8000,
+ .wait_us = 0,
+ .sync = false,
+ },
+ },
+ {
+ .description = "Normal priority and low priority",
+ .client[0] = {
+ .priority = DRM_SCHED_PRIORITY_NORMAL,
+ .job_cnt = 1,
+ .job_us = 8000,
+ .wait_us = 0,
+ .sync = false,
+ },
+ .client[1] = {
+ .priority = DRM_SCHED_PRIORITY_LOW,
+ .job_cnt = 1,
+ .job_us = 8000,
+ .wait_us = 0,
+ .sync = false,
+ },
+ },
+ {
+ .description = "High priority and normal priority",
+ .client[0] = {
+ .priority = DRM_SCHED_PRIORITY_HIGH,
+ .job_cnt = 1,
+ .job_us = 8000,
+ .wait_us = 0,
+ .sync = false,
+ },
+ .client[1] = {
+ .priority = DRM_SCHED_PRIORITY_NORMAL,
+ .job_cnt = 1,
+ .job_us = 8000,
+ .wait_us = 0,
+ .sync = false,
+ },
+ },
+ {
+ .description = "High priority and low priority",
+ .client[0] = {
+ .priority = DRM_SCHED_PRIORITY_HIGH,
+ .job_cnt = 1,
+ .job_us = 8000,
+ .wait_us = 0,
+ .sync = false,
+ },
+ .client[1] = {
+ .priority = DRM_SCHED_PRIORITY_LOW,
+ .job_cnt = 1,
+ .job_us = 8000,
+ .wait_us = 0,
+ .sync = false,
+ },
+ },
+ {
+ .description = "50% and 50%",
+ .client[0] = {
+ .priority = DRM_SCHED_PRIORITY_NORMAL,
+ .job_cnt = 1,
+ .job_us = 1500,
+ .wait_us = 1500,
+ .sync = true,
+ },
+ .client[1] = {
+ .priority = DRM_SCHED_PRIORITY_NORMAL,
+ .job_cnt = 1,
+ .job_us = 2500,
+ .wait_us = 2500,
+ .sync = true,
+ },
+ },
+ {
+ .description = "50% and 50% low priority",
+ .client[0] = {
+ .priority = DRM_SCHED_PRIORITY_NORMAL,
+ .job_cnt = 1,
+ .job_us = 1500,
+ .wait_us = 1500,
+ .sync = true,
+ },
+ .client[1] = {
+ .priority = DRM_SCHED_PRIORITY_LOW,
+ .job_cnt = 1,
+ .job_us = 2500,
+ .wait_us = 2500,
+ .sync = true,
+ },
+ },
+ {
+ .description = "50% high priority and 50%",
+ .client[0] = {
+ .priority = DRM_SCHED_PRIORITY_HIGH,
+ .job_cnt = 1,
+ .job_us = 1500,
+ .wait_us = 1500,
+ .sync = true,
+ },
+ .client[1] = {
+ .priority = DRM_SCHED_PRIORITY_NORMAL,
+ .job_cnt = 1,
+ .job_us = 2500,
+ .wait_us = 2500,
+ .sync = true,
+ },
+ },
+ {
+ .description = "Low priority hog and interactive client",
+ .client[0] = {
+ .priority = DRM_SCHED_PRIORITY_LOW,
+ .job_cnt = 3,
+ .job_us = 2500,
+ .wait_us = 500,
+ .sync = false,
+ },
+ .client[1] = {
+ .priority = DRM_SCHED_PRIORITY_NORMAL,
+ .job_cnt = 1,
+ .job_us = 500,
+ .wait_us = 10000,
+ .sync = true,
+ },
+ },
+ {
+ .description = "Heavy rendering and interactive client",
+ .client[0] = {
+ .priority = DRM_SCHED_PRIORITY_NORMAL,
+ .job_cnt = 3,
+ .job_us = 2500,
+ .wait_us = 2500,
+ .sync = true,
+ },
+ .client[1] = {
+ .priority = DRM_SCHED_PRIORITY_NORMAL,
+ .job_cnt = 1,
+ .job_us = 1000,
+ .wait_us = 9000,
+ .sync = true,
+ },
+ },
+ {
+ .description = "Very heavy rendering and interactive client",
+ .client[0] = {
+ .priority = DRM_SCHED_PRIORITY_NORMAL,
+ .job_cnt = 4,
+ .job_us = 50000,
+ .wait_us = 1,
+ .sync = true,
+ },
+ .client[1] = {
+ .priority = DRM_SCHED_PRIORITY_NORMAL,
+ .job_cnt = 1,
+ .job_us = 1000,
+ .wait_us = 9000,
+ .sync = true,
+ },
+ },
+};
+
+static void
+drm_sched_desc(const struct drm_sched_test_params *params, char *desc)
+{
+ strscpy(desc, params->description, KUNIT_PARAM_DESC_SIZE);
+}
+
+KUNIT_ARRAY_PARAM(drm_sched_scheduler_two_clients,
+ drm_sched_cases,
+ drm_sched_desc);
+
+/*
+ * struct test_client_stats - track client stats
+ *
+ * For each client executing a simulated workload we track some timings for
+ * which we are interested in the minimum of all iterations (@min_us), maximum
+ * (@max_us) and the overall total for all iterations (@tot_us).
+ */
+struct test_client_stats {
+ unsigned int min_us;
+ unsigned int max_us;
+ unsigned long tot_us;
+};
+
+/*
+ * struct test_client - a simulated userspace client submitting scheduler work
+ *
+ * Each client executing a simulated workload is represented by one of these.
+ *
+ * Each of them instantiates a scheduling @entity and executes a workloads as
+ * defined in @params. Based on those @params the theoretical execution time of
+ * the client is calculated as @ideal_duration, while the actual wall time is
+ * tracked in @duration (calculated based on the @start and @end client time-
+ * stamps).
+ *
+ * Numerical @id is assigned to each for logging purposes.
+ *
+ * @worker and @work are used to provide an independent execution context from
+ * which scheduler jobs are submitted.
+ *
+ * During execution statistics on how long it took to submit and execute one
+ * iteration (whether or not synchronous) is kept in @cycle_time, while
+ * @latency_time tracks the @cycle_time minus the ideal duration of the one
+ * cycle.
+ *
+ * Once the client has completed the set number of iterations it will write the
+ * completion status into @done.
+ */
+struct test_client {
+ struct kunit *test; /* Backpointer to the kunit test. */
+
+ struct drm_mock_sched_entity *entity;
+ struct kthread_worker *worker;
+ struct kthread_work work;
+
+ struct drm_sched_client_params params;
+
+ unsigned int id;
+ ktime_t duration;
+ ktime_t ideal_duration;
+ unsigned cycles;
+ unsigned int cycle;
+ ktime_t start;
+ ktime_t end;
+ bool done;
+
+ struct test_client_stats cycle_time;
+ struct test_client_stats latency_time;
+};
+
+static void
+update_stats(struct test_client_stats *stats, unsigned int us)
+{
+ if (us > stats->max_us)
+ stats->max_us = us;
+ if (us < stats->min_us)
+ stats->min_us = us;
+ stats->tot_us += us;
+}
+
+static unsigned int
+get_stats_avg(struct test_client_stats *stats, unsigned int cycles)
+{
+ return div_u64(stats->tot_us, cycles);
+}
+
+static void drm_sched_client_work(struct kthread_work *work)
+{
+ struct test_client *client = container_of(work, typeof(*client), work);
+ const long sync_wait = MAX_SCHEDULE_TIMEOUT;
+ unsigned int cycle, work_us, period_us;
+ struct drm_mock_sched_job *job = NULL;
+
+ work_us = client->params.job_cnt * client->params.job_us;
+ period_us = work_us + client->params.wait_us;
+ client->cycles =
+ DIV_ROUND_UP((unsigned int)ktime_to_us(client->duration),
+ period_us);
+ client->ideal_duration = us_to_ktime(client->cycles * period_us);
+
+ client->start = ktime_get();
+
+ for (cycle = 0; cycle < client->cycles; cycle++) {
+ ktime_t cycle_time;
+ unsigned int batch;
+ unsigned long us;
+
+ if (READ_ONCE(client->done))
+ break;
+
+ cycle_time = ktime_get();
+ for (batch = 0; batch < client->params.job_cnt; batch++) {
+ job = drm_mock_sched_job_new(client->test,
+ client->entity);
+ drm_mock_sched_job_set_duration_us(job,
+ client->params.job_us);
+ drm_mock_sched_job_submit(job);
+ }
+
+ if (client->params.sync)
+ drm_mock_sched_job_wait_finished(job, sync_wait);
+
+ cycle_time = ktime_sub(ktime_get(), cycle_time);
+ us = ktime_to_us(cycle_time);
+ update_stats(&client->cycle_time, us);
+ if (ktime_to_us(cycle_time) >= (long)work_us)
+ us = ktime_to_us(cycle_time) - work_us;
+ else if (WARN_ON_ONCE(client->params.sync)) /* GPU job took less than expected. */
+ us = 0;
+ update_stats(&client->latency_time, us);
+ WRITE_ONCE(client->cycle, cycle);
+
+ if (READ_ONCE(client->done))
+ break;
+
+ if (client->params.wait_us)
+ fsleep(client->params.wait_us);
+ else if (!client->params.sync)
+ cond_resched(); /* Do not hog the CPU if fully async. */
+ }
+
+ client->done = drm_mock_sched_job_wait_finished(job, sync_wait);
+ client->end = ktime_get();
+}
+
+static const char *prio_str(enum drm_sched_priority prio)
+{
+ switch (prio) {
+ case DRM_SCHED_PRIORITY_KERNEL:
+ return "kernel";
+ case DRM_SCHED_PRIORITY_LOW:
+ return "low";
+ case DRM_SCHED_PRIORITY_NORMAL:
+ return "normal";
+ case DRM_SCHED_PRIORITY_HIGH:
+ return "high";
+ default:
+ return "???";
+ }
+}
+
+static bool client_done(struct test_client *client)
+{
+ return READ_ONCE(client->done); /* READ_ONCE to document lockless read from a loop. */
+}
+
+static void drm_sched_scheduler_two_clients_test(struct kunit *test)
+{
+ const struct drm_sched_test_params *params = test->param_value;
+ struct drm_mock_scheduler *sched = test->priv;
+ struct test_client client[2] = { };
+ unsigned int prev_cycle[2] = { };
+ unsigned int i, j;
+ ktime_t start;
+
+ /*
+ * Same job stream from two clients.
+ */
+
+ for (i = 0; i < ARRAY_SIZE(client); i++)
+ client[i].entity =
+ drm_mock_sched_entity_new(test,
+ params->client[i].priority,
+ sched);
+
+ for (i = 0; i < ARRAY_SIZE(client); i++) {
+ client[i].test = test;
+ client[i].id = i;
+ client[i].duration = ms_to_ktime(1000);
+ client[i].params = params->client[i];
+ client[i].cycle_time.min_us = ~0U;
+ client[i].latency_time.min_us = ~0U;
+ client[i].worker =
+ kthread_create_worker(0, "%s-%u", __func__, i);
+ if (IS_ERR(client[i].worker)) {
+ for (j = 0; j < i; j++)
+ kthread_destroy_worker(client[j].worker);
+ KUNIT_FAIL(test, "Failed to create worker!\n");
+ }
+
+ kthread_init_work(&client[i].work, drm_sched_client_work);
+ }
+
+ for (i = 0; i < ARRAY_SIZE(client); i++)
+ kthread_queue_work(client[i].worker, &client[i].work);
+
+ /*
+ * The clients (workers) can be a mix of async (deep submission queue),
+ * sync (one job at a time), or something in between. Therefore it is
+ * difficult to display a single metric representing their progress.
+ *
+ * Each struct drm_sched_client_params describes the actual submission
+ * pattern which happens in the following steps:
+ * 1. Submit N jobs
+ * 2. Wait for last submitted job to finish
+ * 3. Sleep for U micro-seconds
+ * 4. Goto 1. for C cycles
+ *
+ * Where number of cycles is calculated to match the target client
+ * duration from the respective struct drm_sched_test_params.
+ *
+ * To asses scheduling behaviour what we output for both clients is:
+ * - pct: Percentage progress of the jobs submitted
+ * - cps: "Cycles" per second (where one cycle is one complete
+ * iteration from the above)
+ * - qd: Number of outstanding jobs in the client/entity
+ */
+
+ pr_info(
+" [pct] - Job sumission progress\n"
+" [cps] - Cycles per second\n"
+" [qd] - Number of outstanding jobs in the client/entity\n");
+ pr_info("%s:\n\t pct1 cps1 qd1; pct2 cps2 qd2\n",
+ params->description);
+ start = ktime_get();
+ while (!client_done(&client[0]) || !client_done(&client[1])) {
+ const unsigned int period_ms = 100;
+ const unsigned int frequency = 1000 / period_ms;
+ unsigned int pct[2], qd[2], cycle[2], cps[2];
+
+ for (i = 0; i < ARRAY_SIZE(client); i++) {
+ qd[i] = spsc_queue_count(&client[i].entity->base.job_queue);
+ cycle[i] = READ_ONCE(client[i].cycle);
+ cps[i] = DIV_ROUND_UP(100 * frequency *
+ (cycle[i] - prev_cycle[i]),
+ 100);
+ if (client[i].cycles)
+ pct[i] = DIV_ROUND_UP(100 * (1 + cycle[i]),
+ client[i].cycles);
+ else
+ pct[i] = 0;
+ prev_cycle[i] = cycle[i];
+ }
+
+ if (client_done(&client[0]))
+ pr_info("\t+%6lldms: ; %3u %5u %4u\n",
+ ktime_to_ms(ktime_sub(ktime_get(), start)),
+ pct[1], cps[1], qd[1]);
+ else if (client_done(&client[1]))
+ pr_info("\t+%6lldms: %3u %5u %4u;\n",
+ ktime_to_ms(ktime_sub(ktime_get(), start)),
+ pct[0], cps[0], qd[0]);
+ else
+ pr_info("\t+%6lldms: %3u %5u %4u; %3u %5u %4u\n",
+ ktime_to_ms(ktime_sub(ktime_get(), start)),
+ pct[0], cps[0], qd[0],
+ pct[1], cps[1], qd[1]);
+
+ msleep(period_ms);
+ }
+
+ for (i = 0; i < ARRAY_SIZE(client); i++) {
+ kthread_flush_work(&client[i].work);
+ kthread_destroy_worker(client[i].worker);
+ }
+
+ for (i = 0; i < ARRAY_SIZE(client); i++)
+ KUNIT_ASSERT_TRUE(test, client[i].done);
+
+ for (i = 0; i < ARRAY_SIZE(client); i++) {
+ pr_info(" %u: prio=%s sync=%u elapsed_ms=%lldms (ideal_ms=%lldms) cycle_time(min,avg,max)=%u,%u,%u us latency_time(min,avg,max)=%u,%u,%u us",
+ i,
+ prio_str(params->client[i].priority),
+ params->client[i].sync,
+ ktime_to_ms(ktime_sub(client[i].end, client[i].start)),
+ ktime_to_ms(client[i].ideal_duration),
+ client[i].cycle_time.min_us,
+ get_stats_avg(&client[i].cycle_time, client[i].cycles),
+ client[i].cycle_time.max_us,
+ client[i].latency_time.min_us,
+ get_stats_avg(&client[i].latency_time, client[i].cycles),
+ client[i].latency_time.max_us);
+ drm_mock_sched_entity_free(client[i].entity);
+ }
+}
+
+static const struct kunit_attributes drm_sched_scheduler_two_clients_attr = {
+ .speed = KUNIT_SPEED_SLOW,
+};
+
+static struct kunit_case drm_sched_scheduler_two_clients_tests[] = {
+ KUNIT_CASE_PARAM_ATTR(drm_sched_scheduler_two_clients_test,
+ drm_sched_scheduler_two_clients_gen_params,
+ drm_sched_scheduler_two_clients_attr),
+ {}
+};
+
+static struct kunit_suite drm_sched_scheduler_two_clients1 = {
+ .name = "drm_sched_scheduler_two_clients_one_credit_tests",
+ .init = drm_sched_scheduler_init,
+ .exit = drm_sched_scheduler_exit,
+ .test_cases = drm_sched_scheduler_two_clients_tests,
+};
+
+static struct kunit_suite drm_sched_scheduler_two_clients2 = {
+ .name = "drm_sched_scheduler_two_clients_two_credits_tests",
+ .init = drm_sched_scheduler_init2,
+ .exit = drm_sched_scheduler_exit,
+ .test_cases = drm_sched_scheduler_two_clients_tests,
+};
+
+kunit_test_suites(&drm_sched_scheduler_overhead,
+ &drm_sched_scheduler_two_clients1,
+ &drm_sched_scheduler_two_clients2);
--
2.52.0
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH v7 05/29] drm/sched: Add some more scheduling quality unit tests
2026-03-06 16:34 [PATCH v7 00/29] Fair(er) DRM scheduler Tvrtko Ursulin
` (3 preceding siblings ...)
2026-03-06 16:34 ` [PATCH v7 04/29] drm/sched: Add some scheduling quality unit tests Tvrtko Ursulin
@ 2026-03-06 16:34 ` Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 06/29] drm/sched: Implement RR via FIFO Tvrtko Ursulin
` (24 subsequent siblings)
29 siblings, 0 replies; 32+ messages in thread
From: Tvrtko Ursulin @ 2026-03-06 16:34 UTC (permalink / raw)
To: amd-gfx, dri-devel
Cc: kernel-dev, intel-xe, Danilo Krummrich, Philipp Stanner,
Tvrtko Ursulin, Christian König, Matthew Brost,
Pierre-Eric Pelloux-Prayer
This time round we explore the rate of submitted job queue processing
with multiple identical parallel clients.
Example test output:
3 clients:
t cycle: min avg max : ...
+ 0ms 0 0 0 : 0 0 0
+ 102ms 2 2 2 : 2 2 2
+ 208ms 5 6 6 : 6 5 5
+ 310ms 8 9 9 : 9 9 8
...
+ 2616ms 82 83 83 : 83 83 82
+ 2717ms 83 83 83 : 83 83 83
avg_max_min_delta(x100)=60
Every 100ms for the duration of the test test logs how many jobs each
client had completed, prefixed by minimum, average and maximum numbers.
When finished overall average delta between max and min is output as a
rough indicator to scheduling fairness.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Philipp Stanner <phasta@kernel.org>
Cc: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Acked-by: Christian König <christian.koenig@amd.com>
Acked-by: Danilo Krummrich <dakr@kernel.org>
---
.../gpu/drm/scheduler/tests/tests_scheduler.c | 190 +++++++++++++++++-
1 file changed, 189 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/scheduler/tests/tests_scheduler.c b/drivers/gpu/drm/scheduler/tests/tests_scheduler.c
index 4a02bc447914..f33306e70bca 100644
--- a/drivers/gpu/drm/scheduler/tests/tests_scheduler.c
+++ b/drivers/gpu/drm/scheduler/tests/tests_scheduler.c
@@ -195,6 +195,7 @@ struct drm_sched_client_params {
struct drm_sched_test_params {
const char *description;
+ unsigned int num_clients;
struct drm_sched_client_params client[2];
};
@@ -691,6 +692,193 @@ static struct kunit_suite drm_sched_scheduler_two_clients2 = {
.test_cases = drm_sched_scheduler_two_clients_tests,
};
+
+static const struct drm_sched_test_params drm_sched_many_cases[] = {
+ {
+ .description = "2 clients",
+ .num_clients = 2,
+ .client[0] = {
+ .priority = DRM_SCHED_PRIORITY_NORMAL,
+ .job_cnt = 4,
+ .job_us = 1000,
+ .wait_us = 0,
+ .sync = true,
+ },
+ },
+ {
+ .description = "3 clients",
+ .num_clients = 3,
+ .client[0] = {
+ .priority = DRM_SCHED_PRIORITY_NORMAL,
+ .job_cnt = 4,
+ .job_us = 1000,
+ .wait_us = 0,
+ .sync = true,
+ },
+ },
+ {
+ .description = "7 clients",
+ .num_clients = 7,
+ .client[0] = {
+ .priority = DRM_SCHED_PRIORITY_NORMAL,
+ .job_cnt = 4,
+ .job_us = 1000,
+ .wait_us = 0,
+ .sync = true,
+ },
+ },
+ {
+ .description = "13 clients",
+ .num_clients = 13,
+ .client[0] = {
+ .priority = DRM_SCHED_PRIORITY_NORMAL,
+ .job_cnt = 4,
+ .job_us = 1000,
+ .wait_us = 0,
+ .sync = true,
+ },
+ },
+ {
+ .description = "31 clients",
+ .num_clients = 31,
+ .client[0] = {
+ .priority = DRM_SCHED_PRIORITY_NORMAL,
+ .job_cnt = 2,
+ .job_us = 1000,
+ .wait_us = 0,
+ .sync = true,
+ },
+ },
+};
+
+KUNIT_ARRAY_PARAM(drm_sched_scheduler_many_clients,
+ drm_sched_many_cases,
+ drm_sched_desc);
+
+static void drm_sched_scheduler_many_clients_test(struct kunit *test)
+{
+ const struct drm_sched_test_params *params = test->param_value;
+ struct drm_mock_scheduler *sched = test->priv;
+ const unsigned int clients = params->num_clients;
+ unsigned int i, j, delta_total = 0, loops = 0;
+ struct test_client *client;
+ unsigned int *prev_cycle;
+ ktime_t start;
+ char *buf;
+
+ /*
+ * Many clients with deep-ish async queues.
+ */
+
+ buf = kunit_kmalloc(test, PAGE_SIZE, GFP_KERNEL);
+ KUNIT_ASSERT_NOT_NULL(test, buf);
+ client = kunit_kcalloc(test, clients, sizeof(*client), GFP_KERNEL);
+ KUNIT_ASSERT_NOT_NULL(test, client);
+ prev_cycle = kunit_kcalloc(test, clients, sizeof(*prev_cycle),
+ GFP_KERNEL);
+ KUNIT_ASSERT_NOT_NULL(test, prev_cycle);
+
+ for (i = 0; i < clients; i++)
+ client[i].entity =
+ drm_mock_sched_entity_new(test,
+ DRM_SCHED_PRIORITY_NORMAL,
+ sched);
+
+ for (i = 0; i < clients; i++) {
+ client[i].test = test;
+ client[i].id = i;
+ client[i].params = params->client[0];
+ client[i].duration = ms_to_ktime(1000 / clients);
+ client[i].cycle_time.min_us = ~0U;
+ client[i].latency_time.min_us = ~0U;
+ client[i].worker =
+ kthread_create_worker(0, "%s-%u", __func__, i);
+ if (IS_ERR(client[i].worker)) {
+ for (j = 0; j < i; j++)
+ kthread_destroy_worker(client[j].worker);
+ KUNIT_FAIL(test, "Failed to create worker!\n");
+ }
+
+ kthread_init_work(&client[i].work, drm_sched_client_work);
+ }
+
+ for (i = 0; i < clients; i++)
+ kthread_queue_work(client[i].worker, &client[i].work);
+
+ start = ktime_get();
+ pr_info("%u clients:\n\tt\t\tcycle:\t min avg max : ...\n", clients);
+ for (;;) {
+ unsigned int min = ~0;
+ unsigned int max = 0;
+ unsigned int total = 0;
+ bool done = true;
+ char pbuf[16];
+
+ memset(buf, 0, PAGE_SIZE);
+ for (i = 0; i < clients; i++) {
+ unsigned int cycle, cycles;
+
+ /* Read current progress from the threaded worker. */
+ cycle = READ_ONCE(client[i].cycle);
+ cycles = READ_ONCE(client[i].cycles);
+
+ snprintf(pbuf, sizeof(pbuf), " %3d", cycle);
+ strncat(buf, pbuf, PAGE_SIZE);
+
+ total += cycle;
+ if (cycle < min)
+ min = cycle;
+ if (cycle > max)
+ max = cycle;
+
+ if (!min || (cycle + 1) < cycles)
+ done = false;
+ }
+
+ loops++;
+ delta_total += max - min;
+
+ pr_info("\t+%6lldms\t\t %3u %3u %3u :%s\n",
+ ktime_to_ms(ktime_sub(ktime_get(), start)),
+ min, DIV_ROUND_UP(total, clients), max, buf);
+
+ if (done)
+ break;
+
+ msleep(100);
+ }
+
+ pr_info(" avg_max_min_delta(x100)=%u\n",
+ loops ? DIV_ROUND_UP(delta_total * 100, loops) : 0);
+
+ for (i = 0; i < clients; i++) {
+ kthread_flush_work(&client[i].work);
+ kthread_destroy_worker(client[i].worker);
+ }
+
+ for (i = 0; i < clients; i++)
+ drm_mock_sched_entity_free(client[i].entity);
+}
+
+static const struct kunit_attributes drm_sched_scheduler_many_clients_attr = {
+ .speed = KUNIT_SPEED_SLOW,
+};
+
+static struct kunit_case drm_sched_scheduler_many_clients_tests[] = {
+ KUNIT_CASE_PARAM_ATTR(drm_sched_scheduler_many_clients_test,
+ drm_sched_scheduler_many_clients_gen_params,
+ drm_sched_scheduler_many_clients_attr),
+ {}
+};
+
+static struct kunit_suite drm_sched_scheduler_many_clients = {
+ .name = "drm_sched_scheduler_many_clients_tests",
+ .init = drm_sched_scheduler_init2,
+ .exit = drm_sched_scheduler_exit,
+ .test_cases = drm_sched_scheduler_many_clients_tests,
+};
+
kunit_test_suites(&drm_sched_scheduler_overhead,
&drm_sched_scheduler_two_clients1,
- &drm_sched_scheduler_two_clients2);
+ &drm_sched_scheduler_two_clients2,
+ &drm_sched_scheduler_many_clients);
--
2.52.0
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH v7 06/29] drm/sched: Implement RR via FIFO
2026-03-06 16:34 [PATCH v7 00/29] Fair(er) DRM scheduler Tvrtko Ursulin
` (4 preceding siblings ...)
2026-03-06 16:34 ` [PATCH v7 05/29] drm/sched: Add some more " Tvrtko Ursulin
@ 2026-03-06 16:34 ` Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 07/29] drm/sched: Free all finished jobs at once Tvrtko Ursulin
` (23 subsequent siblings)
29 siblings, 0 replies; 32+ messages in thread
From: Tvrtko Ursulin @ 2026-03-06 16:34 UTC (permalink / raw)
To: amd-gfx, dri-devel
Cc: kernel-dev, intel-xe, Danilo Krummrich, Philipp Stanner,
Tvrtko Ursulin, Christian König, Matthew Brost
Round-robin being the non-default policy and unclear how much it is used,
we can notice that it can be implemented using the FIFO data structures if
we only invent a fake submit timestamp which is monotonically increasing
inside drm_sched_rq instances.
So instead of remembering which was the last entity the scheduler worker
picked we can simply bump the picked one to the bottom of the tree, which
ensures round-robin behaviour between all active queued jobs.
If the picked job was the last from a given entity, we remember the
assigned fake timestamp and use it to re-insert the job once it re-joins
the queue. This ensures the job neither overtakes all already queued jobs,
neither it goes last. Instead it keeps the position after the currently
queued jobs and before the ones which haven't yet been queued at the point
the entity left the queue.
Advantage is that we can consolidate to a single code path and remove a
bunch of code. Downside is round-robin mode now needs to lock on the job
pop path but that should not have a measurable performance impact.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Philipp Stanner <phasta@kernel.org>
Acked-by: Danilo Krummrich <dakr@kernel.org>
---
drivers/gpu/drm/scheduler/sched_internal.h | 7 +-
drivers/gpu/drm/scheduler/sched_main.c | 6 +-
drivers/gpu/drm/scheduler/sched_rq.c | 123 +++++++--------------
include/drm/gpu_scheduler.h | 16 ++-
4 files changed, 56 insertions(+), 96 deletions(-)
diff --git a/drivers/gpu/drm/scheduler/sched_internal.h b/drivers/gpu/drm/scheduler/sched_internal.h
index aab63a8721d9..b683cf813469 100644
--- a/drivers/gpu/drm/scheduler/sched_internal.h
+++ b/drivers/gpu/drm/scheduler/sched_internal.h
@@ -24,11 +24,8 @@ void drm_sched_rq_remove_entity(struct drm_sched_rq *rq,
void drm_sched_rq_pop_entity(struct drm_sched_entity *entity);
struct drm_sched_entity *
-drm_sched_rq_select_entity_rr(struct drm_gpu_scheduler *sched,
- struct drm_sched_rq *rq);
-struct drm_sched_entity *
-drm_sched_rq_select_entity_fifo(struct drm_gpu_scheduler *sched,
- struct drm_sched_rq *rq);
+drm_sched_rq_select_entity(struct drm_gpu_scheduler *sched,
+ struct drm_sched_rq *rq);
void drm_sched_entity_select_rq(struct drm_sched_entity *entity);
struct drm_sched_job *drm_sched_entity_pop_job(struct drm_sched_entity *entity);
diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
index 298509e40d69..097ea187d08e 100644
--- a/drivers/gpu/drm/scheduler/sched_main.c
+++ b/drivers/gpu/drm/scheduler/sched_main.c
@@ -892,15 +892,13 @@ void drm_sched_wakeup(struct drm_gpu_scheduler *sched)
static struct drm_sched_entity *
drm_sched_select_entity(struct drm_gpu_scheduler *sched)
{
- struct drm_sched_entity *entity;
+ struct drm_sched_entity *entity = NULL;
int i;
/* Start with the highest priority.
*/
for (i = DRM_SCHED_PRIORITY_KERNEL; i < sched->num_rqs; i++) {
- entity = drm_sched_policy == DRM_SCHED_POLICY_FIFO ?
- drm_sched_rq_select_entity_fifo(sched, sched->sched_rq[i]) :
- drm_sched_rq_select_entity_rr(sched, sched->sched_rq[i]);
+ entity = drm_sched_rq_select_entity(sched, sched->sched_rq[i]);
if (entity)
break;
}
diff --git a/drivers/gpu/drm/scheduler/sched_rq.c b/drivers/gpu/drm/scheduler/sched_rq.c
index cfc18fc7a411..cf03b38c4eb5 100644
--- a/drivers/gpu/drm/scheduler/sched_rq.c
+++ b/drivers/gpu/drm/scheduler/sched_rq.c
@@ -95,8 +95,9 @@ drm_sched_rq_add_entity(struct drm_sched_entity *entity, ktime_t ts)
list_add_tail(&entity->list, &rq->entities);
}
- if (drm_sched_policy == DRM_SCHED_POLICY_FIFO)
- drm_sched_rq_update_fifo_locked(entity, rq, ts);
+ if (drm_sched_policy == DRM_SCHED_POLICY_RR)
+ ts = entity->rr_ts;
+ drm_sched_rq_update_fifo_locked(entity, rq, ts);
spin_unlock(&rq->lock);
spin_unlock(&entity->lock);
@@ -124,15 +125,27 @@ void drm_sched_rq_remove_entity(struct drm_sched_rq *rq,
atomic_dec(rq->sched->score);
list_del_init(&entity->list);
- if (rq->current_entity == entity)
- rq->current_entity = NULL;
-
- if (drm_sched_policy == DRM_SCHED_POLICY_FIFO)
- drm_sched_rq_remove_fifo_locked(entity, rq);
+ drm_sched_rq_remove_fifo_locked(entity, rq);
spin_unlock(&rq->lock);
}
+static ktime_t
+drm_sched_rq_next_rr_ts(struct drm_sched_rq *rq,
+ struct drm_sched_entity *entity)
+{
+ ktime_t ts;
+
+ lockdep_assert_held(&entity->lock);
+ lockdep_assert_held(&rq->lock);
+
+ ts = ktime_add_ns(rq->rr_ts, 1);
+ entity->rr_ts = ts;
+ rq->rr_ts = ts;
+
+ return ts;
+}
+
/**
* drm_sched_rq_pop_entity - pops an entity
* @entity: scheduler entity
@@ -141,88 +154,32 @@ void drm_sched_rq_remove_entity(struct drm_sched_rq *rq,
*/
void drm_sched_rq_pop_entity(struct drm_sched_entity *entity)
{
+ struct drm_sched_job *next_job;
+
/*
* Update the entity's location in the min heap according to
* the timestamp of the next job, if any.
*/
- if (drm_sched_policy == DRM_SCHED_POLICY_FIFO) {
- struct drm_sched_job *next;
-
- next = drm_sched_entity_queue_peek(entity);
- if (next) {
- struct drm_sched_rq *rq;
-
- spin_lock(&entity->lock);
- rq = entity->rq;
- spin_lock(&rq->lock);
- drm_sched_rq_update_fifo_locked(entity, rq,
- next->submit_ts);
- spin_unlock(&rq->lock);
- spin_unlock(&entity->lock);
- }
+ next_job = drm_sched_entity_queue_peek(entity);
+ if (next_job) {
+ struct drm_sched_rq *rq;
+ ktime_t ts;
+
+ spin_lock(&entity->lock);
+ rq = entity->rq;
+ spin_lock(&rq->lock);
+ if (drm_sched_policy == DRM_SCHED_POLICY_FIFO)
+ ts = next_job->submit_ts;
+ else
+ ts = drm_sched_rq_next_rr_ts(rq, entity);
+ drm_sched_rq_update_fifo_locked(entity, rq, ts);
+ spin_unlock(&rq->lock);
+ spin_unlock(&entity->lock);
}
}
/**
- * drm_sched_rq_select_entity_rr - Select an entity which could provide a job to run
- *
- * @sched: the gpu scheduler
- * @rq: scheduler run queue to check.
- *
- * Try to find the next ready entity.
- *
- * Return an entity if one is found; return an error-pointer (!NULL) if an
- * entity was ready, but the scheduler had insufficient credits to accommodate
- * its job; return NULL, if no ready entity was found.
- */
-struct drm_sched_entity *
-drm_sched_rq_select_entity_rr(struct drm_gpu_scheduler *sched,
- struct drm_sched_rq *rq)
-{
- struct drm_sched_entity *entity;
-
- spin_lock(&rq->lock);
-
- entity = rq->current_entity;
- if (entity) {
- list_for_each_entry_continue(entity, &rq->entities, list) {
- if (drm_sched_entity_is_ready(entity))
- goto found;
- }
- }
-
- list_for_each_entry(entity, &rq->entities, list) {
- if (drm_sched_entity_is_ready(entity))
- goto found;
-
- if (entity == rq->current_entity)
- break;
- }
-
- spin_unlock(&rq->lock);
-
- return NULL;
-
-found:
- if (!drm_sched_can_queue(sched, entity)) {
- /*
- * If scheduler cannot take more jobs signal the caller to not
- * consider lower priority queues.
- */
- entity = ERR_PTR(-ENOSPC);
- } else {
- rq->current_entity = entity;
- reinit_completion(&entity->entity_idle);
- }
-
- spin_unlock(&rq->lock);
-
- return entity;
-}
-
-/**
- * drm_sched_rq_select_entity_fifo - Select an entity which provides a job to run
- *
+ * drm_sched_rq_select_entity - Select an entity which provides a job to run
* @sched: the gpu scheduler
* @rq: scheduler run queue to check.
*
@@ -233,8 +190,8 @@ drm_sched_rq_select_entity_rr(struct drm_gpu_scheduler *sched,
* its job; return NULL, if no ready entity was found.
*/
struct drm_sched_entity *
-drm_sched_rq_select_entity_fifo(struct drm_gpu_scheduler *sched,
- struct drm_sched_rq *rq)
+drm_sched_rq_select_entity(struct drm_gpu_scheduler *sched,
+ struct drm_sched_rq *rq)
{
struct rb_node *rb;
diff --git a/include/drm/gpu_scheduler.h b/include/drm/gpu_scheduler.h
index 78e07c2507c7..2b3eaf623f68 100644
--- a/include/drm/gpu_scheduler.h
+++ b/include/drm/gpu_scheduler.h
@@ -94,7 +94,8 @@ struct drm_sched_entity {
* @lock:
*
* Lock protecting the run-queue (@rq) to which this entity belongs,
- * @priority and the list of schedulers (@sched_list, @num_sched_list).
+ * @priority, the list of schedulers (@sched_list, @num_sched_list) and
+ * the @rr_ts field.
*/
spinlock_t lock;
@@ -142,6 +143,13 @@ struct drm_sched_entity {
*/
enum drm_sched_priority priority;
+ /**
+ * @rr_ts:
+ *
+ * Fake timestamp of the last popped job from the entity.
+ */
+ ktime_t rr_ts;
+
/**
* @job_queue: the list of jobs of this entity.
*/
@@ -239,8 +247,8 @@ struct drm_sched_entity {
* struct drm_sched_rq - queue of entities to be scheduled.
*
* @sched: the scheduler to which this rq belongs to.
- * @lock: protects @entities, @rb_tree_root and @current_entity.
- * @current_entity: the entity which is to be scheduled.
+ * @lock: protects @entities, @rb_tree_root and @rr_ts.
+ * @rr_ts: monotonically incrementing fake timestamp for RR mode.
* @entities: list of the entities to be scheduled.
* @rb_tree_root: root of time based priority queue of entities for FIFO scheduling
*
@@ -253,7 +261,7 @@ struct drm_sched_rq {
spinlock_t lock;
/* Following members are protected by the @lock: */
- struct drm_sched_entity *current_entity;
+ ktime_t rr_ts;
struct list_head entities;
struct rb_root_cached rb_tree_root;
};
--
2.52.0
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH v7 07/29] drm/sched: Free all finished jobs at once
2026-03-06 16:34 [PATCH v7 00/29] Fair(er) DRM scheduler Tvrtko Ursulin
` (5 preceding siblings ...)
2026-03-06 16:34 ` [PATCH v7 06/29] drm/sched: Implement RR via FIFO Tvrtko Ursulin
@ 2026-03-06 16:34 ` Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 08/29] drm/sched: Account entity GPU time Tvrtko Ursulin
` (22 subsequent siblings)
29 siblings, 0 replies; 32+ messages in thread
From: Tvrtko Ursulin @ 2026-03-06 16:34 UTC (permalink / raw)
To: amd-gfx, dri-devel
Cc: kernel-dev, intel-xe, Danilo Krummrich, Philipp Stanner,
Tvrtko Ursulin, Christian König, Matthew Brost
To implement fair scheduling we will need as accurate as possible view
into per entity GPU time utilisation. Because sched fence execution time
are only adjusted for accuracy in the free worker we need to process
completed jobs as soon as possible so the metric is most up to date when
view from the submission side of things.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Philipp Stanner <phasta@kernel.org>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Acked-by: Danilo Krummrich <dakr@kernel.org>
---
drivers/gpu/drm/scheduler/sched_main.c | 13 ++-----------
1 file changed, 2 insertions(+), 11 deletions(-)
diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
index 097ea187d08e..046686a83699 100644
--- a/drivers/gpu/drm/scheduler/sched_main.c
+++ b/drivers/gpu/drm/scheduler/sched_main.c
@@ -910,7 +910,6 @@ drm_sched_select_entity(struct drm_gpu_scheduler *sched)
* drm_sched_get_finished_job - fetch the next finished job to be destroyed
*
* @sched: scheduler instance
- * @have_more: are there more finished jobs on the list
*
* Informs the caller through @have_more whether there are more finished jobs
* besides the returned one.
@@ -919,7 +918,7 @@ drm_sched_select_entity(struct drm_gpu_scheduler *sched)
* ready for it to be destroyed.
*/
static struct drm_sched_job *
-drm_sched_get_finished_job(struct drm_gpu_scheduler *sched, bool *have_more)
+drm_sched_get_finished_job(struct drm_gpu_scheduler *sched)
{
struct drm_sched_job *job, *next;
@@ -934,7 +933,6 @@ drm_sched_get_finished_job(struct drm_gpu_scheduler *sched, bool *have_more)
/* cancel this job's TO timer */
cancel_delayed_work(&sched->work_tdr);
- *have_more = false;
next = list_first_entry_or_null(&sched->pending_list,
typeof(*next), list);
if (next) {
@@ -944,8 +942,6 @@ drm_sched_get_finished_job(struct drm_gpu_scheduler *sched, bool *have_more)
next->s_fence->scheduled.timestamp =
dma_fence_timestamp(&job->s_fence->finished);
- *have_more = dma_fence_is_signaled(&next->s_fence->finished);
-
/* start TO timer for next job */
drm_sched_start_timeout(sched);
}
@@ -1004,14 +1000,9 @@ static void drm_sched_free_job_work(struct work_struct *w)
struct drm_gpu_scheduler *sched =
container_of(w, struct drm_gpu_scheduler, work_free_job);
struct drm_sched_job *job;
- bool have_more;
- job = drm_sched_get_finished_job(sched, &have_more);
- if (job) {
+ while ((job = drm_sched_get_finished_job(sched)))
sched->ops->free_job(job);
- if (have_more)
- drm_sched_run_free_queue(sched);
- }
drm_sched_run_job_queue(sched);
}
--
2.52.0
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH v7 08/29] drm/sched: Account entity GPU time
2026-03-06 16:34 [PATCH v7 00/29] Fair(er) DRM scheduler Tvrtko Ursulin
` (6 preceding siblings ...)
2026-03-06 16:34 ` [PATCH v7 07/29] drm/sched: Free all finished jobs at once Tvrtko Ursulin
@ 2026-03-06 16:34 ` Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 09/29] drm/sched: Remove idle entity from tree Tvrtko Ursulin
` (21 subsequent siblings)
29 siblings, 0 replies; 32+ messages in thread
From: Tvrtko Ursulin @ 2026-03-06 16:34 UTC (permalink / raw)
To: amd-gfx, dri-devel
Cc: kernel-dev, intel-xe, Danilo Krummrich, Philipp Stanner,
Tvrtko Ursulin, Christian König, Matthew Brost
To implement fair scheduling we need a view into the GPU time consumed by
entities. Problem we have is that jobs and entities objects have decoupled
lifetimes, where at the point we have a view into accurate GPU time, we
cannot link back to the entity any longer.
Solve this by adding a light weight entity stats object which is reference
counted by both entity and the job and hence can safely be used from
either side.
With that, the only other thing we need is to add a helper for adding the
job's GPU time into the respective entity stats object, and call it once
the accurate GPU time has been calculated.
The most convenient place to do that is the free job worker for several
reasons. Doing the accounting from the job completion callback would mean
a few locks would need to become irq safe and we would also need to worry
about out of order completions (via dma_fence_is_signaled calls which we
cannot control). In-order completions are critical for GPU time accuracy
which is currently adjusted per fence in the free worker and requires
looking at the next job in the scheduler pending list. We would also need
to add a new lock to protect the scheduler average stats update.
In contrast to those complications, having the accounting done from the
free worker is serialized by definition and all the above complications
are avoided. Downside is there is potential for a time lag between job
completions and GPU time being accounted against the entity. Since that is
partly alleviated by batch processing the completed job queue, and the
scheduling algorithm does not attempt to be completely fair, which would
even be rather impossible to achieve in the GPU world with the current
DRM scheduler design and hardware with no or poor preemption support,
this downside is not considered critical. Plus, in practice the scheduler
is also affected by worker scheduling delays from other angles too. Not
least being able to promptly feed the GPU with new work.
We therefore choose the simple option and can later consider improving
upon it if the need arises.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Philipp Stanner <phasta@kernel.org>
Acked-by: Danilo Krummrich <dakr@kernel.org>
---
drivers/gpu/drm/scheduler/sched_entity.c | 58 ++++++++++++++++++++++
drivers/gpu/drm/scheduler/sched_internal.h | 48 ++++++++++++++++++
drivers/gpu/drm/scheduler/sched_main.c | 6 ++-
include/drm/gpu_scheduler.h | 12 +++++
4 files changed, 123 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.c
index 768f11510129..591cb9f82608 100644
--- a/drivers/gpu/drm/scheduler/sched_entity.c
+++ b/drivers/gpu/drm/scheduler/sched_entity.c
@@ -32,6 +32,58 @@
#include "gpu_scheduler_trace.h"
+
+/**
+ * drm_sched_entity_stats_release - Entity stats kref release function
+ * @kref: Entity stats embedded kref pointer
+ */
+void drm_sched_entity_stats_release(struct kref *kref)
+{
+ struct drm_sched_entity_stats *stats =
+ container_of(kref, typeof(*stats), kref);
+
+ kfree(stats);
+}
+
+/**
+ * drm_sched_entity_stats_new - Allocate a new struct drm_sched_entity_stats object
+ *
+ * Return: Pointer to newly allocated struct drm_sched_entity_stats object.
+ */
+static struct drm_sched_entity_stats *drm_sched_entity_stats_new(void)
+{
+ struct drm_sched_entity_stats *stats;
+
+ stats = kzalloc(sizeof(*stats), GFP_KERNEL);
+ if (!stats)
+ return NULL;
+
+ kref_init(&stats->kref);
+ spin_lock_init(&stats->lock);
+
+ return stats;
+}
+
+/**
+ * drm_sched_entity_stats_job_add_gpu_time - Account job execution time to entity
+ * @job: Scheduler job to account.
+ *
+ * Accounts the execution time of @job to its respective entity stats object.
+ */
+void drm_sched_entity_stats_job_add_gpu_time(struct drm_sched_job *job)
+{
+ struct drm_sched_entity_stats *stats = job->entity_stats;
+ struct drm_sched_fence *s_fence = job->s_fence;
+ ktime_t start, end;
+
+ start = dma_fence_timestamp(&s_fence->scheduled);
+ end = dma_fence_timestamp(&s_fence->finished);
+
+ spin_lock(&stats->lock);
+ stats->runtime = ktime_add(stats->runtime, ktime_sub(end, start));
+ spin_unlock(&stats->lock);
+}
+
/**
* drm_sched_entity_init - Init a context entity used by scheduler when
* submit to HW ring.
@@ -65,6 +117,11 @@ int drm_sched_entity_init(struct drm_sched_entity *entity,
return -EINVAL;
memset(entity, 0, sizeof(struct drm_sched_entity));
+
+ entity->stats = drm_sched_entity_stats_new();
+ if (!entity->stats)
+ return -ENOMEM;
+
INIT_LIST_HEAD(&entity->list);
entity->rq = NULL;
entity->guilty = guilty;
@@ -338,6 +395,7 @@ void drm_sched_entity_fini(struct drm_sched_entity *entity)
dma_fence_put(rcu_dereference_check(entity->last_scheduled, true));
RCU_INIT_POINTER(entity->last_scheduled, NULL);
+ drm_sched_entity_stats_put(entity->stats);
}
EXPORT_SYMBOL(drm_sched_entity_fini);
diff --git a/drivers/gpu/drm/scheduler/sched_internal.h b/drivers/gpu/drm/scheduler/sched_internal.h
index b683cf813469..be5d99c641c5 100644
--- a/drivers/gpu/drm/scheduler/sched_internal.h
+++ b/drivers/gpu/drm/scheduler/sched_internal.h
@@ -3,6 +3,26 @@
#ifndef _DRM_GPU_SCHEDULER_INTERNAL_H_
#define _DRM_GPU_SCHEDULER_INTERNAL_H_
+#include <linux/ktime.h>
+#include <linux/kref.h>
+#include <linux/spinlock.h>
+
+/**
+ * struct drm_sched_entity_stats - execution stats for an entity.
+ * @kref: reference count for the object.
+ * @lock: lock guarding the @runtime updates.
+ * @runtime: time entity spent on the GPU.
+ *
+ * Because jobs and entities have decoupled lifetimes, ie. we cannot access the
+ * entity once the job has been de-queued, and we do need know how much GPU time
+ * each entity has spent, we need to track this in a separate object which is
+ * reference counted by both entities and jobs.
+ */
+struct drm_sched_entity_stats {
+ struct kref kref;
+ spinlock_t lock;
+ ktime_t runtime;
+};
/* Used to choose between FIFO and RR job-scheduling */
extern int drm_sched_policy;
@@ -95,4 +115,32 @@ drm_sched_entity_is_ready(struct drm_sched_entity *entity)
return true;
}
+void drm_sched_entity_stats_release(struct kref *kref);
+
+/**
+ * drm_sched_entity_stats_get - Obtain a reference count on &struct drm_sched_entity_stats object
+ * @stats: struct drm_sched_entity_stats pointer
+ *
+ * Return: struct drm_sched_entity_stats pointer
+ */
+static inline struct drm_sched_entity_stats *
+drm_sched_entity_stats_get(struct drm_sched_entity_stats *stats)
+{
+ kref_get(&stats->kref);
+
+ return stats;
+}
+
+/**
+ * drm_sched_entity_stats_put - Release a reference count on &struct drm_sched_entity_stats object
+ * @stats: struct drm_sched_entity_stats pointer
+ */
+static inline void
+drm_sched_entity_stats_put(struct drm_sched_entity_stats *stats)
+{
+ kref_put(&stats->kref, drm_sched_entity_stats_release);
+}
+
+void drm_sched_entity_stats_job_add_gpu_time(struct drm_sched_job *job);
+
#endif
diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
index 046686a83699..826ef4e0180a 100644
--- a/drivers/gpu/drm/scheduler/sched_main.c
+++ b/drivers/gpu/drm/scheduler/sched_main.c
@@ -661,6 +661,7 @@ void drm_sched_job_arm(struct drm_sched_job *job)
job->sched = sched;
job->s_priority = entity->priority;
+ job->entity_stats = drm_sched_entity_stats_get(entity->stats);
drm_sched_fence_init(job->s_fence, job->entity);
}
@@ -850,6 +851,7 @@ void drm_sched_job_cleanup(struct drm_sched_job *job)
* been called.
*/
dma_fence_put(&job->s_fence->finished);
+ drm_sched_entity_stats_put(job->entity_stats);
} else {
/* The job was aborted before it has been committed to be run;
* notably, drm_sched_job_arm() has not been called.
@@ -1001,8 +1003,10 @@ static void drm_sched_free_job_work(struct work_struct *w)
container_of(w, struct drm_gpu_scheduler, work_free_job);
struct drm_sched_job *job;
- while ((job = drm_sched_get_finished_job(sched)))
+ while ((job = drm_sched_get_finished_job(sched))) {
+ drm_sched_entity_stats_job_add_gpu_time(job);
sched->ops->free_job(job);
+ }
drm_sched_run_job_queue(sched);
}
diff --git a/include/drm/gpu_scheduler.h b/include/drm/gpu_scheduler.h
index 2b3eaf623f68..bf31c4c58a4c 100644
--- a/include/drm/gpu_scheduler.h
+++ b/include/drm/gpu_scheduler.h
@@ -71,6 +71,8 @@ enum drm_sched_priority {
DRM_SCHED_PRIORITY_COUNT
};
+struct drm_sched_entity_stats;
+
/**
* struct drm_sched_entity - A wrapper around a job queue (typically
* attached to the DRM file_priv).
@@ -110,6 +112,11 @@ struct drm_sched_entity {
*/
struct drm_sched_rq *rq;
+ /**
+ * @stats: Stats object reference held by the entity and jobs.
+ */
+ struct drm_sched_entity_stats *stats;
+
/**
* @sched_list:
*
@@ -365,6 +372,11 @@ struct drm_sched_job {
struct drm_sched_fence *s_fence;
struct drm_sched_entity *entity;
+ /**
+ * @entity_stats: Stats object reference held by the job and entity.
+ */
+ struct drm_sched_entity_stats *entity_stats;
+
enum drm_sched_priority s_priority;
u32 credits;
/** @last_dependency: tracks @dependencies as they signal */
--
2.52.0
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH v7 09/29] drm/sched: Remove idle entity from tree
2026-03-06 16:34 [PATCH v7 00/29] Fair(er) DRM scheduler Tvrtko Ursulin
` (7 preceding siblings ...)
2026-03-06 16:34 ` [PATCH v7 08/29] drm/sched: Account entity GPU time Tvrtko Ursulin
@ 2026-03-06 16:34 ` Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 10/29] drm/sched: Add fair scheduling policy Tvrtko Ursulin
` (20 subsequent siblings)
29 siblings, 0 replies; 32+ messages in thread
From: Tvrtko Ursulin @ 2026-03-06 16:34 UTC (permalink / raw)
To: amd-gfx, dri-devel
Cc: kernel-dev, intel-xe, Danilo Krummrich, Philipp Stanner,
Tvrtko Ursulin, Christian König, Matthew Brost
There is no need to keep entities with no jobs in the tree so lets remove
it once the last job is consumed. This keeps the tree smaller which is
nicer and more efficient as entities are removed and re-added on every
popped job.
Apart from that, the upcoming fair scheduling algorithm will rely on the
tree only containing runnable entities.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Philipp Stanner <phasta@kernel.org>
Acked-by: Danilo Krummrich <dakr@kernel.org>
---
drivers/gpu/drm/scheduler/sched_rq.c | 18 ++++++++++++------
1 file changed, 12 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/scheduler/sched_rq.c b/drivers/gpu/drm/scheduler/sched_rq.c
index cf03b38c4eb5..2d1f579d8352 100644
--- a/drivers/gpu/drm/scheduler/sched_rq.c
+++ b/drivers/gpu/drm/scheduler/sched_rq.c
@@ -19,6 +19,9 @@ drm_sched_entity_compare_before(struct rb_node *a, const struct rb_node *b)
static void drm_sched_rq_remove_fifo_locked(struct drm_sched_entity *entity,
struct drm_sched_rq *rq)
{
+ lockdep_assert_held(&entity->lock);
+ lockdep_assert_held(&rq->lock);
+
if (!RB_EMPTY_NODE(&entity->rb_tree_node)) {
rb_erase_cached(&entity->rb_tree_node, &rq->rb_tree_root);
RB_CLEAR_NODE(&entity->rb_tree_node);
@@ -155,27 +158,30 @@ drm_sched_rq_next_rr_ts(struct drm_sched_rq *rq,
void drm_sched_rq_pop_entity(struct drm_sched_entity *entity)
{
struct drm_sched_job *next_job;
+ struct drm_sched_rq *rq;
/*
* Update the entity's location in the min heap according to
* the timestamp of the next job, if any.
*/
+ spin_lock(&entity->lock);
+ rq = entity->rq;
+ spin_lock(&rq->lock);
next_job = drm_sched_entity_queue_peek(entity);
if (next_job) {
- struct drm_sched_rq *rq;
ktime_t ts;
- spin_lock(&entity->lock);
- rq = entity->rq;
- spin_lock(&rq->lock);
if (drm_sched_policy == DRM_SCHED_POLICY_FIFO)
ts = next_job->submit_ts;
else
ts = drm_sched_rq_next_rr_ts(rq, entity);
+
drm_sched_rq_update_fifo_locked(entity, rq, ts);
- spin_unlock(&rq->lock);
- spin_unlock(&entity->lock);
+ } else {
+ drm_sched_rq_remove_fifo_locked(entity, rq);
}
+ spin_unlock(&rq->lock);
+ spin_unlock(&entity->lock);
}
/**
--
2.52.0
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH v7 10/29] drm/sched: Add fair scheduling policy
2026-03-06 16:34 [PATCH v7 00/29] Fair(er) DRM scheduler Tvrtko Ursulin
` (8 preceding siblings ...)
2026-03-06 16:34 ` [PATCH v7 09/29] drm/sched: Remove idle entity from tree Tvrtko Ursulin
@ 2026-03-06 16:34 ` Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 11/29] drm/sched: Favour interactive clients slightly Tvrtko Ursulin
` (19 subsequent siblings)
29 siblings, 0 replies; 32+ messages in thread
From: Tvrtko Ursulin @ 2026-03-06 16:34 UTC (permalink / raw)
To: amd-gfx, dri-devel
Cc: kernel-dev, intel-xe, Danilo Krummrich, Philipp Stanner,
Tvrtko Ursulin, Christian König, Matthew Brost,
Pierre-Eric Pelloux-Prayer
The FAIR scheduling policy is built upon the same concepts as the well
known CFS CPU scheduler - entity run queue is sorted by the virtual GPU
time consumed by entities in a way that the entity with least vruntime
runs first.
It is able to avoid total priority starvation, which is one of the
problems with FIFO, and it also does not need for per priority run queues.
As it scales the actual GPU runtime by an exponential factor as the
priority decreases, the virtual runtime for low priority entities grows
faster than for normal priority, pushing them further down the runqueue
order for the same real GPU time spent.
Apart from this fundamental fairness, fair policy is especially strong in
oversubscription workloads where it is able to give more GPU time to short
and bursty workloads when they are running in parallel with GPU heavy
clients submitting deep job queues.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Philipp Stanner <phasta@kernel.org>
Cc: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Acked-by: Danilo Krummrich <dakr@kernel.org>
---
drivers/gpu/drm/scheduler/sched_entity.c | 28 ++--
drivers/gpu/drm/scheduler/sched_internal.h | 5 +
drivers/gpu/drm/scheduler/sched_main.c | 12 +-
drivers/gpu/drm/scheduler/sched_rq.c | 177 ++++++++++++++++++++-
include/drm/gpu_scheduler.h | 17 +-
5 files changed, 219 insertions(+), 20 deletions(-)
diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.c
index 591cb9f82608..94438f80b00d 100644
--- a/drivers/gpu/drm/scheduler/sched_entity.c
+++ b/drivers/gpu/drm/scheduler/sched_entity.c
@@ -127,6 +127,8 @@ int drm_sched_entity_init(struct drm_sched_entity *entity,
entity->guilty = guilty;
entity->priority = priority;
entity->last_user = current->group_leader;
+ entity->rq_priority = drm_sched_policy == DRM_SCHED_POLICY_FAIR ?
+ DRM_SCHED_PRIORITY_KERNEL : priority;
entity->num_sched_list = num_sched_list;
entity->sched_list = num_sched_list > 1 ? sched_list : NULL;
RCU_INIT_POINTER(entity->last_scheduled, NULL);
@@ -139,17 +141,23 @@ int drm_sched_entity_init(struct drm_sched_entity *entity,
*/
pr_warn("%s: called with uninitialized scheduler\n", __func__);
} else {
- /* The "priority" of an entity cannot exceed the number of run-queues of a
- * scheduler. Protect against num_rqs being 0, by converting to signed. Choose
- * the lowest priority available.
+ enum drm_sched_priority p = entity->priority;
+
+ /*
+ * The "priority" of an entity cannot exceed the number of
+ * run-queues of a scheduler. Protect against num_rqs being 0,
+ * by converting to signed. Choose the lowest priority
+ * available.
*/
- if (entity->priority >= sched_list[0]->num_rqs) {
- dev_err(sched_list[0]->dev, "entity has out-of-bounds priority: %u. num_rqs: %u\n",
- entity->priority, sched_list[0]->num_rqs);
- entity->priority = max_t(s32, (s32) sched_list[0]->num_rqs - 1,
- (s32) DRM_SCHED_PRIORITY_KERNEL);
+ if (p >= sched_list[0]->num_user_rqs) {
+ dev_err(sched_list[0]->dev, "entity with out-of-bounds priority:%u num_user_rqs:%u\n",
+ p, sched_list[0]->num_user_rqs);
+ p = max_t(s32,
+ (s32)sched_list[0]->num_user_rqs - 1,
+ (s32)DRM_SCHED_PRIORITY_KERNEL);
+ entity->priority = p;
}
- entity->rq = sched_list[0]->sched_rq[entity->priority];
+ entity->rq = sched_list[0]->sched_rq[entity->rq_priority];
}
init_completion(&entity->entity_idle);
@@ -586,7 +594,7 @@ void drm_sched_entity_select_rq(struct drm_sched_entity *entity)
spin_lock(&entity->lock);
sched = drm_sched_pick_best(entity->sched_list, entity->num_sched_list);
- rq = sched ? sched->sched_rq[entity->priority] : NULL;
+ rq = sched ? sched->sched_rq[entity->rq_priority] : NULL;
if (rq != entity->rq) {
drm_sched_rq_remove_entity(entity->rq, entity);
entity->rq = rq;
diff --git a/drivers/gpu/drm/scheduler/sched_internal.h b/drivers/gpu/drm/scheduler/sched_internal.h
index be5d99c641c5..a682e0cfbf25 100644
--- a/drivers/gpu/drm/scheduler/sched_internal.h
+++ b/drivers/gpu/drm/scheduler/sched_internal.h
@@ -12,6 +12,8 @@
* @kref: reference count for the object.
* @lock: lock guarding the @runtime updates.
* @runtime: time entity spent on the GPU.
+ * @prev_runtime: previous @runtime used to get the runtime delta.
+ * @vruntime: virtual runtime as accumulated by the fair algorithm.
*
* Because jobs and entities have decoupled lifetimes, ie. we cannot access the
* entity once the job has been de-queued, and we do need know how much GPU time
@@ -22,6 +24,8 @@ struct drm_sched_entity_stats {
struct kref kref;
spinlock_t lock;
ktime_t runtime;
+ ktime_t prev_runtime;
+ ktime_t vruntime;
};
/* Used to choose between FIFO and RR job-scheduling */
@@ -29,6 +33,7 @@ extern int drm_sched_policy;
#define DRM_SCHED_POLICY_RR 0
#define DRM_SCHED_POLICY_FIFO 1
+#define DRM_SCHED_POLICY_FAIR 2
bool drm_sched_can_queue(struct drm_gpu_scheduler *sched,
struct drm_sched_entity *entity);
diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
index 826ef4e0180a..0aca41b4e334 100644
--- a/drivers/gpu/drm/scheduler/sched_main.c
+++ b/drivers/gpu/drm/scheduler/sched_main.c
@@ -90,7 +90,7 @@ int drm_sched_policy = DRM_SCHED_POLICY_FIFO;
* DOC: sched_policy (int)
* Used to override default entities scheduling policy in a run queue.
*/
-MODULE_PARM_DESC(sched_policy, "Specify the scheduling policy for entities on a run-queue, " __stringify(DRM_SCHED_POLICY_RR) " = Round Robin, " __stringify(DRM_SCHED_POLICY_FIFO) " = FIFO (default).");
+MODULE_PARM_DESC(sched_policy, "Specify the scheduling policy for entities on a run-queue, " __stringify(DRM_SCHED_POLICY_RR) " = Round Robin, " __stringify(DRM_SCHED_POLICY_FIFO) " = FIFO (default), " __stringify(DRM_SCHED_POLICY_FAIR) " = Fair.");
module_param_named(sched_policy, drm_sched_policy, int, 0444);
static u32 drm_sched_available_credits(struct drm_gpu_scheduler *sched)
@@ -1141,11 +1141,13 @@ int drm_sched_init(struct drm_gpu_scheduler *sched, const struct drm_sched_init_
sched->own_submit_wq = true;
}
- sched->sched_rq = kmalloc_objs(*sched->sched_rq, args->num_rqs,
- GFP_KERNEL | __GFP_ZERO);
+ sched->num_user_rqs = args->num_rqs;
+ sched->num_rqs = drm_sched_policy != DRM_SCHED_POLICY_FAIR ?
+ args->num_rqs : 1;
+ sched->sched_rq = kzalloc_objs(*sched->sched_rq, args->num_rqs);
if (!sched->sched_rq)
goto Out_check_own;
- sched->num_rqs = args->num_rqs;
+
for (i = DRM_SCHED_PRIORITY_KERNEL; i < sched->num_rqs; i++) {
sched->sched_rq[i] = kzalloc_obj(*sched->sched_rq[i]);
if (!sched->sched_rq[i])
@@ -1258,7 +1260,7 @@ void drm_sched_increase_karma(struct drm_sched_job *bad)
if (bad->s_priority != DRM_SCHED_PRIORITY_KERNEL) {
atomic_inc(&bad->karma);
- for (i = DRM_SCHED_PRIORITY_HIGH; i < sched->num_rqs; i++) {
+ for (i = DRM_SCHED_PRIORITY_KERNEL; i < sched->num_rqs; i++) {
struct drm_sched_rq *rq = sched->sched_rq[i];
spin_lock(&rq->lock);
diff --git a/drivers/gpu/drm/scheduler/sched_rq.c b/drivers/gpu/drm/scheduler/sched_rq.c
index 2d1f579d8352..2fde309d02a6 100644
--- a/drivers/gpu/drm/scheduler/sched_rq.c
+++ b/drivers/gpu/drm/scheduler/sched_rq.c
@@ -16,6 +16,35 @@ drm_sched_entity_compare_before(struct rb_node *a, const struct rb_node *b)
return ktime_before(ea->oldest_job_waiting, eb->oldest_job_waiting);
}
+static void drm_sched_rq_update_prio(struct drm_sched_rq *rq)
+{
+ enum drm_sched_priority prio = DRM_SCHED_PRIORITY_INVALID;
+ struct rb_node *rb;
+
+ lockdep_assert_held(&rq->lock);
+
+ rb = rb_first_cached(&rq->rb_tree_root);
+ if (rb) {
+ struct drm_sched_entity *entity =
+ rb_entry(rb, typeof(*entity), rb_tree_node);
+
+ /*
+ * The normal locking order is entity then run-queue so taking
+ * the entity lock here would be a locking inversion for the
+ * case when the current head of the run-queue is different from
+ * the one we already have locked. The unlocked read is fine
+ * though, because if the priority had just changed it is no big
+ * deal for our algorithm, but just a transient reachable only
+ * by drivers with userspace dynamic priority changes API. Equal
+ * in effect to the priority change becoming visible a few
+ * instructions later.
+ */
+ prio = READ_ONCE(entity->priority);
+ }
+
+ rq->head_prio = prio;
+}
+
static void drm_sched_rq_remove_fifo_locked(struct drm_sched_entity *entity,
struct drm_sched_rq *rq)
{
@@ -25,6 +54,7 @@ static void drm_sched_rq_remove_fifo_locked(struct drm_sched_entity *entity,
if (!RB_EMPTY_NODE(&entity->rb_tree_node)) {
rb_erase_cached(&entity->rb_tree_node, &rq->rb_tree_root);
RB_CLEAR_NODE(&entity->rb_tree_node);
+ drm_sched_rq_update_prio(rq);
}
}
@@ -46,6 +76,7 @@ static void drm_sched_rq_update_fifo_locked(struct drm_sched_entity *entity,
rb_add_cached(&entity->rb_tree_node, &rq->rb_tree_root,
drm_sched_entity_compare_before);
+ drm_sched_rq_update_prio(rq);
}
/**
@@ -62,6 +93,133 @@ void drm_sched_rq_init(struct drm_gpu_scheduler *sched,
INIT_LIST_HEAD(&rq->entities);
rq->rb_tree_root = RB_ROOT_CACHED;
rq->sched = sched;
+ rq->head_prio = DRM_SCHED_PRIORITY_INVALID;
+}
+
+/*
+ * Core part of the CFS-like algorithm is that the virtual runtime of lower
+ * priority tasks should grow quicker than the higher priority ones, so that
+ * when we then schedule entities with the aim of keeping their accumulated
+ * virtual time balanced, we can approach fair distribution of GPU time.
+ *
+ * For converting the real GPU time into virtual we pick some multipliers with
+ * the idea to achieve the following GPU time distribution:
+ *
+ * - Kernel priority gets roughly 2x GPU time compared to high.
+ * - High gets ~4x relative to normal.
+ * - Normal gets ~8x relative to low.
+ */
+static const unsigned int vruntime_shift[] = {
+ [DRM_SCHED_PRIORITY_KERNEL] = 1,
+ [DRM_SCHED_PRIORITY_HIGH] = 2,
+ [DRM_SCHED_PRIORITY_NORMAL] = 4,
+ [DRM_SCHED_PRIORITY_LOW] = 7,
+};
+
+static ktime_t
+drm_sched_rq_get_min_vruntime(struct drm_sched_rq *rq)
+{
+ ktime_t vruntime = 0;
+ struct rb_node *rb;
+
+ lockdep_assert_held(&rq->lock);
+
+ rb = rb_first_cached(&rq->rb_tree_root);
+ if (rb) {
+ struct drm_sched_entity *entity =
+ rb_entry(rb, typeof(*entity), rb_tree_node);
+ struct drm_sched_entity_stats *stats = entity->stats;
+
+ spin_lock(&stats->lock);
+ vruntime = stats->vruntime;
+ spin_unlock(&stats->lock);
+ }
+
+ return vruntime;
+}
+
+static void
+drm_sched_entity_save_vruntime(struct drm_sched_entity *entity,
+ ktime_t min_vruntime)
+{
+ struct drm_sched_entity_stats *stats = entity->stats;
+ ktime_t vruntime;
+
+ spin_lock(&stats->lock);
+ vruntime = stats->vruntime;
+ if (min_vruntime && vruntime > min_vruntime)
+ vruntime = ktime_sub(vruntime, min_vruntime);
+ else
+ vruntime = 0;
+ stats->vruntime = vruntime;
+ spin_unlock(&stats->lock);
+}
+
+static ktime_t
+drm_sched_entity_restore_vruntime(struct drm_sched_entity *entity,
+ ktime_t min_vruntime,
+ enum drm_sched_priority rq_prio)
+{
+ struct drm_sched_entity_stats *stats = entity->stats;
+ enum drm_sched_priority prio = entity->priority;
+ ktime_t vruntime;
+
+ BUILD_BUG_ON(DRM_SCHED_PRIORITY_NORMAL < DRM_SCHED_PRIORITY_HIGH);
+
+ spin_lock(&stats->lock);
+ vruntime = stats->vruntime;
+
+ /*
+ * Special handling for entities which were picked from the top of the
+ * queue and are now re-joining the top with another one already there.
+ */
+ if (!vruntime && rq_prio != DRM_SCHED_PRIORITY_INVALID) {
+ if (prio > rq_prio) {
+ /*
+ * Lower priority should not overtake higher when re-
+ * joining at the top of the queue.
+ */
+ vruntime = ns_to_ktime(prio - rq_prio);
+ } else if (prio < rq_prio) {
+ /*
+ * Higher priority can go first.
+ */
+ vruntime = -ns_to_ktime(rq_prio - prio);
+ }
+ }
+
+ /*
+ * Restore saved relative position in the queue.
+ */
+ vruntime = ktime_add(min_vruntime, vruntime);
+
+ stats->vruntime = vruntime;
+ spin_unlock(&stats->lock);
+
+ return vruntime;
+}
+
+static ktime_t drm_sched_entity_update_vruntime(struct drm_sched_entity *entity)
+{
+ struct drm_sched_entity_stats *stats = entity->stats;
+ ktime_t runtime, prev;
+
+ spin_lock(&stats->lock);
+ prev = stats->prev_runtime;
+ runtime = stats->runtime;
+ stats->prev_runtime = runtime;
+ runtime = ktime_add_ns(stats->vruntime,
+ ktime_to_ns(ktime_sub(runtime, prev)) <<
+ vruntime_shift[entity->priority]);
+ stats->vruntime = runtime;
+ spin_unlock(&stats->lock);
+
+ return runtime;
+}
+
+static ktime_t drm_sched_entity_get_job_ts(struct drm_sched_entity *entity)
+{
+ return drm_sched_entity_update_vruntime(entity);
}
/**
@@ -98,8 +256,14 @@ drm_sched_rq_add_entity(struct drm_sched_entity *entity, ktime_t ts)
list_add_tail(&entity->list, &rq->entities);
}
- if (drm_sched_policy == DRM_SCHED_POLICY_RR)
+ if (drm_sched_policy == DRM_SCHED_POLICY_FAIR) {
+ ts = drm_sched_rq_get_min_vruntime(rq);
+ ts = drm_sched_entity_restore_vruntime(entity, ts,
+ rq->head_prio);
+ } else if (drm_sched_policy == DRM_SCHED_POLICY_RR) {
ts = entity->rr_ts;
+ }
+
drm_sched_rq_update_fifo_locked(entity, rq, ts);
spin_unlock(&rq->lock);
@@ -171,7 +335,9 @@ void drm_sched_rq_pop_entity(struct drm_sched_entity *entity)
if (next_job) {
ktime_t ts;
- if (drm_sched_policy == DRM_SCHED_POLICY_FIFO)
+ if (drm_sched_policy == DRM_SCHED_POLICY_FAIR)
+ ts = drm_sched_entity_get_job_ts(entity);
+ else if (drm_sched_policy == DRM_SCHED_POLICY_FIFO)
ts = next_job->submit_ts;
else
ts = drm_sched_rq_next_rr_ts(rq, entity);
@@ -179,6 +345,13 @@ void drm_sched_rq_pop_entity(struct drm_sched_entity *entity)
drm_sched_rq_update_fifo_locked(entity, rq, ts);
} else {
drm_sched_rq_remove_fifo_locked(entity, rq);
+
+ if (drm_sched_policy == DRM_SCHED_POLICY_FAIR) {
+ ktime_t min_vruntime;
+
+ min_vruntime = drm_sched_rq_get_min_vruntime(rq);
+ drm_sched_entity_save_vruntime(entity, min_vruntime);
+ }
}
spin_unlock(&rq->lock);
spin_unlock(&entity->lock);
diff --git a/include/drm/gpu_scheduler.h b/include/drm/gpu_scheduler.h
index bf31c4c58a4c..dd514a413156 100644
--- a/include/drm/gpu_scheduler.h
+++ b/include/drm/gpu_scheduler.h
@@ -63,6 +63,7 @@ struct drm_file;
* to an array, and as such should start at 0.
*/
enum drm_sched_priority {
+ DRM_SCHED_PRIORITY_INVALID = -1, /* Internal marker - do not use. */
DRM_SCHED_PRIORITY_KERNEL,
DRM_SCHED_PRIORITY_HIGH,
DRM_SCHED_PRIORITY_NORMAL,
@@ -150,6 +151,11 @@ struct drm_sched_entity {
*/
enum drm_sched_priority priority;
+ /**
+ * @rq_priority: Run-queue priority
+ */
+ enum drm_sched_priority rq_priority;
+
/**
* @rr_ts:
*
@@ -254,10 +260,11 @@ struct drm_sched_entity {
* struct drm_sched_rq - queue of entities to be scheduled.
*
* @sched: the scheduler to which this rq belongs to.
- * @lock: protects @entities, @rb_tree_root and @rr_ts.
+ * @lock: protects @entities, @rb_tree_root, @rr_ts and @head_prio.
* @rr_ts: monotonically incrementing fake timestamp for RR mode.
* @entities: list of the entities to be scheduled.
* @rb_tree_root: root of time based priority queue of entities for FIFO scheduling
+ * @head_prio: priority of the top tree element.
*
* Run queue is a set of entities scheduling command submissions for
* one specific ring. It implements the scheduling policy that selects
@@ -271,6 +278,7 @@ struct drm_sched_rq {
ktime_t rr_ts;
struct list_head entities;
struct rb_root_cached rb_tree_root;
+ enum drm_sched_priority head_prio;
};
/**
@@ -563,8 +571,10 @@ struct drm_sched_backend_ops {
* @credit_count: the current credit count of this scheduler
* @timeout: the time after which a job is removed from the scheduler.
* @name: name of the ring for which this scheduler is being used.
- * @num_rqs: Number of run-queues. This is at most DRM_SCHED_PRIORITY_COUNT,
- * as there's usually one run-queue per priority, but could be less.
+ * @num_user_rqs: Number of run-queues. This is at most
+ * DRM_SCHED_PRIORITY_COUNT, as there's usually one run-queue per
+ * priority, but could be less.
+ * @num_rqs: Equal to @num_user_rqs for FIFO and RR and 1 for the FAIR policy.
* @sched_rq: An allocated array of run-queues of size @num_rqs;
* @job_scheduled: once drm_sched_entity_flush() is called the scheduler
* waits on this wait queue until all the scheduled jobs are
@@ -597,6 +607,7 @@ struct drm_gpu_scheduler {
long timeout;
const char *name;
u32 num_rqs;
+ u32 num_user_rqs;
struct drm_sched_rq **sched_rq;
wait_queue_head_t job_scheduled;
atomic64_t job_id_count;
--
2.52.0
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH v7 11/29] drm/sched: Favour interactive clients slightly
2026-03-06 16:34 [PATCH v7 00/29] Fair(er) DRM scheduler Tvrtko Ursulin
` (9 preceding siblings ...)
2026-03-06 16:34 ` [PATCH v7 10/29] drm/sched: Add fair scheduling policy Tvrtko Ursulin
@ 2026-03-06 16:34 ` Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 12/29] drm/sched: Switch default policy to fair Tvrtko Ursulin
` (18 subsequent siblings)
29 siblings, 0 replies; 32+ messages in thread
From: Tvrtko Ursulin @ 2026-03-06 16:34 UTC (permalink / raw)
To: amd-gfx, dri-devel
Cc: kernel-dev, intel-xe, Danilo Krummrich, Philipp Stanner,
Tvrtko Ursulin, Christian König, Matthew Brost,
Pierre-Eric Pelloux-Prayer
GPUs do not always implement preemption and DRM scheduler definitely
does not support it at the front end scheduling level. This means
execution quanta can be quite long and is controlled by userspace,
consequence of which is picking the "wrong" entity to run can have a
larger negative effect than it would have with a virtual runtime based CPU
scheduler.
Another important consideration is that rendering clients often have
shallow submission queues, meaning they will be entering and exiting the
scheduler's runnable queue often.
Relevant scenario here is what happens when an entity re-joins the
runnable queue with other entities already present. One cornerstone of the
virtual runtime algorithm is to let it re-join at the head and rely on the
virtual runtime accounting and timeslicing to sort it out.
However, as explained above, this may not work perfectly in the GPU world.
Entity could always get to overtake the existing entities, or not,
depending on the submission order and rbtree equal key insertion
behaviour.
Allow interactive jobs to overtake entities already queued up for the
limited case when interactive entity is re-joining the queue after
being idle.
This gives more opportunity for the compositors to have their rendering
executed before the GPU hogs even if they have been configured with the
same scheduling priority.
To classify a client as interactive we look at its average job duration
versus the average for the whole scheduler. We can track this easily by
plugging into the existing job runtime tracking and applying the
exponential moving average window on the past submissions. Then, all other
things being equal, we let the more interactive jobs go first.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Philipp Stanner <phasta@kernel.org>
Cc: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Acked-by: Danilo Krummrich <dakr@kernel.org>
---
drivers/gpu/drm/scheduler/sched_entity.c | 13 ++++++++++---
drivers/gpu/drm/scheduler/sched_internal.h | 5 ++++-
drivers/gpu/drm/scheduler/sched_main.c | 8 +++++++-
drivers/gpu/drm/scheduler/sched_rq.c | 22 ++++++++++++++++++++--
include/drm/gpu_scheduler.h | 5 +++++
5 files changed, 46 insertions(+), 7 deletions(-)
diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.c
index 94438f80b00d..add99c609faf 100644
--- a/drivers/gpu/drm/scheduler/sched_entity.c
+++ b/drivers/gpu/drm/scheduler/sched_entity.c
@@ -60,6 +60,7 @@ static struct drm_sched_entity_stats *drm_sched_entity_stats_new(void)
kref_init(&stats->kref);
spin_lock_init(&stats->lock);
+ ewma_drm_sched_avgtime_init(&stats->avg_job_us);
return stats;
}
@@ -69,19 +70,25 @@ static struct drm_sched_entity_stats *drm_sched_entity_stats_new(void)
* @job: Scheduler job to account.
*
* Accounts the execution time of @job to its respective entity stats object.
+ *
+ * Return: Job's real duration in micro seconds.
*/
-void drm_sched_entity_stats_job_add_gpu_time(struct drm_sched_job *job)
+ktime_t drm_sched_entity_stats_job_add_gpu_time(struct drm_sched_job *job)
{
struct drm_sched_entity_stats *stats = job->entity_stats;
struct drm_sched_fence *s_fence = job->s_fence;
- ktime_t start, end;
+ ktime_t start, end, duration;
start = dma_fence_timestamp(&s_fence->scheduled);
end = dma_fence_timestamp(&s_fence->finished);
+ duration = ktime_sub(end, start);
spin_lock(&stats->lock);
- stats->runtime = ktime_add(stats->runtime, ktime_sub(end, start));
+ stats->runtime = ktime_add(stats->runtime, duration);
+ ewma_drm_sched_avgtime_add(&stats->avg_job_us, ktime_to_us(duration));
spin_unlock(&stats->lock);
+
+ return duration;
}
/**
diff --git a/drivers/gpu/drm/scheduler/sched_internal.h b/drivers/gpu/drm/scheduler/sched_internal.h
index a682e0cfbf25..ba5a9d9786e1 100644
--- a/drivers/gpu/drm/scheduler/sched_internal.h
+++ b/drivers/gpu/drm/scheduler/sched_internal.h
@@ -14,6 +14,7 @@
* @runtime: time entity spent on the GPU.
* @prev_runtime: previous @runtime used to get the runtime delta.
* @vruntime: virtual runtime as accumulated by the fair algorithm.
+ * @avg_job_us: average job duration.
*
* Because jobs and entities have decoupled lifetimes, ie. we cannot access the
* entity once the job has been de-queued, and we do need know how much GPU time
@@ -26,6 +27,8 @@ struct drm_sched_entity_stats {
ktime_t runtime;
ktime_t prev_runtime;
ktime_t vruntime;
+
+ struct ewma_drm_sched_avgtime avg_job_us;
};
/* Used to choose between FIFO and RR job-scheduling */
@@ -146,6 +149,6 @@ drm_sched_entity_stats_put(struct drm_sched_entity_stats *stats)
kref_put(&stats->kref, drm_sched_entity_stats_release);
}
-void drm_sched_entity_stats_job_add_gpu_time(struct drm_sched_job *job);
+ktime_t drm_sched_entity_stats_job_add_gpu_time(struct drm_sched_job *job);
#endif
diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
index 0aca41b4e334..337db7b1e688 100644
--- a/drivers/gpu/drm/scheduler/sched_main.c
+++ b/drivers/gpu/drm/scheduler/sched_main.c
@@ -1004,7 +1004,12 @@ static void drm_sched_free_job_work(struct work_struct *w)
struct drm_sched_job *job;
while ((job = drm_sched_get_finished_job(sched))) {
- drm_sched_entity_stats_job_add_gpu_time(job);
+ ktime_t duration = drm_sched_entity_stats_job_add_gpu_time(job);
+
+ /* Serialized by the worker. */
+ ewma_drm_sched_avgtime_add(&sched->avg_job_us,
+ ktime_to_us(duration));
+
sched->ops->free_job(job);
}
@@ -1165,6 +1170,7 @@ int drm_sched_init(struct drm_gpu_scheduler *sched, const struct drm_sched_init_
atomic_set(&sched->_score, 0);
atomic64_set(&sched->job_id_count, 0);
sched->pause_submit = false;
+ ewma_drm_sched_avgtime_init(&sched->avg_job_us);
sched->ready = true;
return 0;
diff --git a/drivers/gpu/drm/scheduler/sched_rq.c b/drivers/gpu/drm/scheduler/sched_rq.c
index 2fde309d02a6..f8bc60026a73 100644
--- a/drivers/gpu/drm/scheduler/sched_rq.c
+++ b/drivers/gpu/drm/scheduler/sched_rq.c
@@ -161,13 +161,21 @@ drm_sched_entity_restore_vruntime(struct drm_sched_entity *entity,
enum drm_sched_priority rq_prio)
{
struct drm_sched_entity_stats *stats = entity->stats;
+ struct drm_gpu_scheduler *sched = entity->rq->sched;
enum drm_sched_priority prio = entity->priority;
+ unsigned long avg_us, sched_avg_us;
ktime_t vruntime;
BUILD_BUG_ON(DRM_SCHED_PRIORITY_NORMAL < DRM_SCHED_PRIORITY_HIGH);
spin_lock(&stats->lock);
vruntime = stats->vruntime;
+ avg_us = ewma_drm_sched_avgtime_read(&stats->avg_job_us);
+ /*
+ * Unlocked read of the scheduler average is fine since it is just
+ * heuristics and data type is a natural word size.
+ */
+ sched_avg_us = ewma_drm_sched_avgtime_read(&sched->avg_job_us);
/*
* Special handling for entities which were picked from the top of the
@@ -177,14 +185,24 @@ drm_sched_entity_restore_vruntime(struct drm_sched_entity *entity,
if (prio > rq_prio) {
/*
* Lower priority should not overtake higher when re-
- * joining at the top of the queue.
+ * joining at the top of the queue so push it back
+ * somewhere behind the "middle" of the run-queue,
+ * proportional to the scheduler and entity average job
+ * durations.
*/
- vruntime = ns_to_ktime(prio - rq_prio);
+ vruntime = us_to_ktime((1 + avg_us + sched_avg_us) <<
+ vruntime_shift[prio]);
} else if (prio < rq_prio) {
/*
* Higher priority can go first.
*/
vruntime = -ns_to_ktime(rq_prio - prio);
+ } else {
+ /* Favour entity with shorter jobs (interactivity). */
+ if (avg_us <= sched_avg_us)
+ vruntime = -ns_to_ktime(1);
+ else
+ vruntime = ns_to_ktime(1);
}
}
diff --git a/include/drm/gpu_scheduler.h b/include/drm/gpu_scheduler.h
index dd514a413156..826de4cbbf2d 100644
--- a/include/drm/gpu_scheduler.h
+++ b/include/drm/gpu_scheduler.h
@@ -25,11 +25,14 @@
#define _DRM_GPU_SCHEDULER_H_
#include <drm/spsc_queue.h>
+#include <linux/average.h>
#include <linux/dma-fence.h>
#include <linux/completion.h>
#include <linux/xarray.h>
#include <linux/workqueue.h>
+DECLARE_EWMA(drm_sched_avgtime, 6, 4);
+
#define MAX_WAIT_SCHED_ENTITY_Q_EMPTY msecs_to_jiffies(1000)
/**
@@ -582,6 +585,7 @@ struct drm_sched_backend_ops {
* @job_id_count: used to assign unique id to the each job.
* @submit_wq: workqueue used to queue @work_run_job and @work_free_job
* @timeout_wq: workqueue used to queue @work_tdr
+ * @avg_job_us: Average job duration.
* @work_run_job: work which calls run_job op of each scheduler.
* @work_free_job: work which calls free_job op of each scheduler.
* @work_tdr: schedules a delayed call to @drm_sched_job_timedout after the
@@ -613,6 +617,7 @@ struct drm_gpu_scheduler {
atomic64_t job_id_count;
struct workqueue_struct *submit_wq;
struct workqueue_struct *timeout_wq;
+ struct ewma_drm_sched_avgtime avg_job_us;
struct work_struct work_run_job;
struct work_struct work_free_job;
struct delayed_work work_tdr;
--
2.52.0
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH v7 12/29] drm/sched: Switch default policy to fair
2026-03-06 16:34 [PATCH v7 00/29] Fair(er) DRM scheduler Tvrtko Ursulin
` (10 preceding siblings ...)
2026-03-06 16:34 ` [PATCH v7 11/29] drm/sched: Favour interactive clients slightly Tvrtko Ursulin
@ 2026-03-06 16:34 ` Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 13/29] drm/sched: Remove FIFO and RR and simplify to a single run queue Tvrtko Ursulin
` (17 subsequent siblings)
29 siblings, 0 replies; 32+ messages in thread
From: Tvrtko Ursulin @ 2026-03-06 16:34 UTC (permalink / raw)
To: amd-gfx, dri-devel
Cc: kernel-dev, intel-xe, Danilo Krummrich, Philipp Stanner,
Tvrtko Ursulin, Christian König, Matthew Brost,
Pierre-Eric Pelloux-Prayer
FAIR policy works better than FIFO for all known use cases and either
matches or gets close to RR. Lets make it a default to improve the user
experience especially with interactive workloads competing with heavy
clients.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Philipp Stanner <phasta@kernel.org>
Cc: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Acked-by: Danilo Krummrich <dakr@kernel.org>
---
drivers/gpu/drm/scheduler/sched_main.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
index 337db7b1e688..8127c93a1718 100644
--- a/drivers/gpu/drm/scheduler/sched_main.c
+++ b/drivers/gpu/drm/scheduler/sched_main.c
@@ -84,13 +84,13 @@
#define CREATE_TRACE_POINTS
#include "gpu_scheduler_trace.h"
-int drm_sched_policy = DRM_SCHED_POLICY_FIFO;
+int drm_sched_policy = DRM_SCHED_POLICY_FAIR;
/**
* DOC: sched_policy (int)
* Used to override default entities scheduling policy in a run queue.
*/
-MODULE_PARM_DESC(sched_policy, "Specify the scheduling policy for entities on a run-queue, " __stringify(DRM_SCHED_POLICY_RR) " = Round Robin, " __stringify(DRM_SCHED_POLICY_FIFO) " = FIFO (default), " __stringify(DRM_SCHED_POLICY_FAIR) " = Fair.");
+MODULE_PARM_DESC(sched_policy, "Specify the scheduling policy for entities on a run-queue, " __stringify(DRM_SCHED_POLICY_RR) " = Round Robin, " __stringify(DRM_SCHED_POLICY_FIFO) " = FIFO, " __stringify(DRM_SCHED_POLICY_FAIR) " = Fair (default).");
module_param_named(sched_policy, drm_sched_policy, int, 0444);
static u32 drm_sched_available_credits(struct drm_gpu_scheduler *sched)
--
2.52.0
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH v7 13/29] drm/sched: Remove FIFO and RR and simplify to a single run queue
2026-03-06 16:34 [PATCH v7 00/29] Fair(er) DRM scheduler Tvrtko Ursulin
` (11 preceding siblings ...)
2026-03-06 16:34 ` [PATCH v7 12/29] drm/sched: Switch default policy to fair Tvrtko Ursulin
@ 2026-03-06 16:34 ` Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 14/29] drm/sched: Embed run queue singleton into the scheduler Tvrtko Ursulin
` (16 subsequent siblings)
29 siblings, 0 replies; 32+ messages in thread
From: Tvrtko Ursulin @ 2026-03-06 16:34 UTC (permalink / raw)
To: amd-gfx, dri-devel
Cc: kernel-dev, intel-xe, Danilo Krummrich, Philipp Stanner,
Tvrtko Ursulin, Christian König, Matthew Brost
Since the new FAIR policy is in general better than FIFO and almost as
good as round-robin in interactive use cases, plus the latter has not been
the default policy in a long time, we can afford to remove both and leave
just FAIR.
By doing so we can simplify the scheduler code by making the scheduler to
run queue relationship always 1:1 and remove some code.
Also, now that the FIFO policy is gone the tree of entities is not a FIFO
tree any more so rename it to just the tree.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Philipp Stanner <phasta@kernel.org>
Acked-by: Danilo Krummrich <dakr@kernel.org>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_job.c | 23 ++---
drivers/gpu/drm/scheduler/sched_entity.c | 29 +-----
drivers/gpu/drm/scheduler/sched_internal.h | 12 +--
drivers/gpu/drm/scheduler/sched_main.c | 108 ++++-----------------
drivers/gpu/drm/scheduler/sched_rq.c | 73 ++++----------
include/drm/gpu_scheduler.h | 36 +------
6 files changed, 57 insertions(+), 224 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
index affc4a3f995b..7d6ff0b6ca4e 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
@@ -483,25 +483,22 @@ drm_sched_entity_queue_pop(struct drm_sched_entity *entity)
void amdgpu_job_stop_all_jobs_on_sched(struct drm_gpu_scheduler *sched)
{
+ struct drm_sched_rq *rq = sched->rq;
+ struct drm_sched_entity *s_entity;
struct drm_sched_job *s_job;
- struct drm_sched_entity *s_entity = NULL;
- int i;
/* Signal all jobs not yet scheduled */
- for (i = DRM_SCHED_PRIORITY_KERNEL; i < sched->num_rqs; i++) {
- struct drm_sched_rq *rq = sched->sched_rq[i];
- spin_lock(&rq->lock);
- list_for_each_entry(s_entity, &rq->entities, list) {
- while ((s_job = drm_sched_entity_queue_pop(s_entity))) {
- struct drm_sched_fence *s_fence = s_job->s_fence;
+ spin_lock(&rq->lock);
+ list_for_each_entry(s_entity, &rq->entities, list) {
+ while ((s_job = drm_sched_entity_queue_pop(s_entity))) {
+ struct drm_sched_fence *s_fence = s_job->s_fence;
- dma_fence_signal(&s_fence->scheduled);
- dma_fence_set_error(&s_fence->finished, -EHWPOISON);
- dma_fence_signal(&s_fence->finished);
- }
+ dma_fence_signal(&s_fence->scheduled);
+ dma_fence_set_error(&s_fence->finished, -EHWPOISON);
+ dma_fence_signal(&s_fence->finished);
}
- spin_unlock(&rq->lock);
}
+ spin_unlock(&rq->lock);
/* Signal all jobs already scheduled to HW */
list_for_each_entry(s_job, &sched->pending_list, list) {
diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.c
index add99c609faf..713ae46f7bbd 100644
--- a/drivers/gpu/drm/scheduler/sched_entity.c
+++ b/drivers/gpu/drm/scheduler/sched_entity.c
@@ -134,37 +134,19 @@ int drm_sched_entity_init(struct drm_sched_entity *entity,
entity->guilty = guilty;
entity->priority = priority;
entity->last_user = current->group_leader;
- entity->rq_priority = drm_sched_policy == DRM_SCHED_POLICY_FAIR ?
- DRM_SCHED_PRIORITY_KERNEL : priority;
entity->num_sched_list = num_sched_list;
entity->sched_list = num_sched_list > 1 ? sched_list : NULL;
RCU_INIT_POINTER(entity->last_scheduled, NULL);
RB_CLEAR_NODE(&entity->rb_tree_node);
- if (!sched_list[0]->sched_rq) {
+ if (!sched_list[0]->rq) {
/* Since every entry covered by num_sched_list
* should be non-NULL and therefore we warn drivers
* not to do this and to fix their DRM calling order.
*/
pr_warn("%s: called with uninitialized scheduler\n", __func__);
} else {
- enum drm_sched_priority p = entity->priority;
-
- /*
- * The "priority" of an entity cannot exceed the number of
- * run-queues of a scheduler. Protect against num_rqs being 0,
- * by converting to signed. Choose the lowest priority
- * available.
- */
- if (p >= sched_list[0]->num_user_rqs) {
- dev_err(sched_list[0]->dev, "entity with out-of-bounds priority:%u num_user_rqs:%u\n",
- p, sched_list[0]->num_user_rqs);
- p = max_t(s32,
- (s32)sched_list[0]->num_user_rqs - 1,
- (s32)DRM_SCHED_PRIORITY_KERNEL);
- entity->priority = p;
- }
- entity->rq = sched_list[0]->sched_rq[entity->rq_priority];
+ entity->rq = sched_list[0]->rq;
}
init_completion(&entity->entity_idle);
@@ -601,7 +583,7 @@ void drm_sched_entity_select_rq(struct drm_sched_entity *entity)
spin_lock(&entity->lock);
sched = drm_sched_pick_best(entity->sched_list, entity->num_sched_list);
- rq = sched ? sched->sched_rq[entity->rq_priority] : NULL;
+ rq = sched ? sched->rq : NULL;
if (rq != entity->rq) {
drm_sched_rq_remove_entity(entity->rq, entity);
entity->rq = rq;
@@ -626,7 +608,6 @@ void drm_sched_entity_push_job(struct drm_sched_job *sched_job)
{
struct drm_sched_entity *entity = sched_job->entity;
bool first;
- ktime_t submit_ts;
trace_drm_sched_job_queue(sched_job, entity);
@@ -643,16 +624,14 @@ void drm_sched_entity_push_job(struct drm_sched_job *sched_job)
/*
* After the sched_job is pushed into the entity queue, it may be
* completed and freed up at any time. We can no longer access it.
- * Make sure to set the submit_ts first, to avoid a race.
*/
- sched_job->submit_ts = submit_ts = ktime_get();
first = spsc_queue_push(&entity->job_queue, &sched_job->queue_node);
/* first job wakes up scheduler */
if (first) {
struct drm_gpu_scheduler *sched;
- sched = drm_sched_rq_add_entity(entity, submit_ts);
+ sched = drm_sched_rq_add_entity(entity);
if (sched)
drm_sched_wakeup(sched);
}
diff --git a/drivers/gpu/drm/scheduler/sched_internal.h b/drivers/gpu/drm/scheduler/sched_internal.h
index ba5a9d9786e1..520a421cbf8d 100644
--- a/drivers/gpu/drm/scheduler/sched_internal.h
+++ b/drivers/gpu/drm/scheduler/sched_internal.h
@@ -31,13 +31,6 @@ struct drm_sched_entity_stats {
struct ewma_drm_sched_avgtime avg_job_us;
};
-/* Used to choose between FIFO and RR job-scheduling */
-extern int drm_sched_policy;
-
-#define DRM_SCHED_POLICY_RR 0
-#define DRM_SCHED_POLICY_FIFO 1
-#define DRM_SCHED_POLICY_FAIR 2
-
bool drm_sched_can_queue(struct drm_gpu_scheduler *sched,
struct drm_sched_entity *entity);
void drm_sched_wakeup(struct drm_gpu_scheduler *sched);
@@ -46,14 +39,13 @@ void drm_sched_rq_init(struct drm_gpu_scheduler *sched,
struct drm_sched_rq *rq);
struct drm_gpu_scheduler *
-drm_sched_rq_add_entity(struct drm_sched_entity *entity, ktime_t ts);
+drm_sched_rq_add_entity(struct drm_sched_entity *entity);
void drm_sched_rq_remove_entity(struct drm_sched_rq *rq,
struct drm_sched_entity *entity);
void drm_sched_rq_pop_entity(struct drm_sched_entity *entity);
struct drm_sched_entity *
-drm_sched_rq_select_entity(struct drm_gpu_scheduler *sched,
- struct drm_sched_rq *rq);
+drm_sched_select_entity(struct drm_gpu_scheduler *sched);
void drm_sched_entity_select_rq(struct drm_sched_entity *entity);
struct drm_sched_job *drm_sched_entity_pop_job(struct drm_sched_entity *entity);
diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
index 8127c93a1718..79e44ccefdc9 100644
--- a/drivers/gpu/drm/scheduler/sched_main.c
+++ b/drivers/gpu/drm/scheduler/sched_main.c
@@ -84,15 +84,6 @@
#define CREATE_TRACE_POINTS
#include "gpu_scheduler_trace.h"
-int drm_sched_policy = DRM_SCHED_POLICY_FAIR;
-
-/**
- * DOC: sched_policy (int)
- * Used to override default entities scheduling policy in a run queue.
- */
-MODULE_PARM_DESC(sched_policy, "Specify the scheduling policy for entities on a run-queue, " __stringify(DRM_SCHED_POLICY_RR) " = Round Robin, " __stringify(DRM_SCHED_POLICY_FIFO) " = FIFO, " __stringify(DRM_SCHED_POLICY_FAIR) " = Fair (default).");
-module_param_named(sched_policy, drm_sched_policy, int, 0444);
-
static u32 drm_sched_available_credits(struct drm_gpu_scheduler *sched)
{
u32 credits;
@@ -880,34 +871,6 @@ void drm_sched_wakeup(struct drm_gpu_scheduler *sched)
drm_sched_run_job_queue(sched);
}
-/**
- * drm_sched_select_entity - Select next entity to process
- *
- * @sched: scheduler instance
- *
- * Return an entity to process or NULL if none are found.
- *
- * Note, that we break out of the for-loop when "entity" is non-null, which can
- * also be an error-pointer--this assures we don't process lower priority
- * run-queues. See comments in the respectively called functions.
- */
-static struct drm_sched_entity *
-drm_sched_select_entity(struct drm_gpu_scheduler *sched)
-{
- struct drm_sched_entity *entity = NULL;
- int i;
-
- /* Start with the highest priority.
- */
- for (i = DRM_SCHED_PRIORITY_KERNEL; i < sched->num_rqs; i++) {
- entity = drm_sched_rq_select_entity(sched, sched->sched_rq[i]);
- if (entity)
- break;
- }
-
- return IS_ERR(entity) ? NULL : entity;
-}
-
/**
* drm_sched_get_finished_job - fetch the next finished job to be destroyed
*
@@ -1033,7 +996,7 @@ static void drm_sched_run_job_work(struct work_struct *w)
/* Find entity with a ready job */
entity = drm_sched_select_entity(sched);
- if (!entity) {
+ if (IS_ERR_OR_NULL(entity)) {
/*
* Either no more work to do, or the next ready job needs more
* credits than the scheduler has currently available.
@@ -1109,8 +1072,6 @@ static struct workqueue_struct *drm_sched_alloc_wq(const char *name)
*/
int drm_sched_init(struct drm_gpu_scheduler *sched, const struct drm_sched_init_args *args)
{
- int i;
-
sched->ops = args->ops;
sched->credit_limit = args->credit_limit;
sched->name = args->name;
@@ -1120,13 +1081,7 @@ int drm_sched_init(struct drm_gpu_scheduler *sched, const struct drm_sched_init_
sched->score = args->score ? args->score : &sched->_score;
sched->dev = args->dev;
- if (args->num_rqs > DRM_SCHED_PRIORITY_COUNT) {
- /* This is a gross violation--tell drivers what the problem is.
- */
- dev_err(sched->dev, "%s: num_rqs cannot be greater than DRM_SCHED_PRIORITY_COUNT\n",
- __func__);
- return -EINVAL;
- } else if (sched->sched_rq) {
+ if (sched->rq) {
/* Not an error, but warn anyway so drivers can
* fine-tune their DRM calling order, and return all
* is good.
@@ -1146,19 +1101,11 @@ int drm_sched_init(struct drm_gpu_scheduler *sched, const struct drm_sched_init_
sched->own_submit_wq = true;
}
- sched->num_user_rqs = args->num_rqs;
- sched->num_rqs = drm_sched_policy != DRM_SCHED_POLICY_FAIR ?
- args->num_rqs : 1;
- sched->sched_rq = kzalloc_objs(*sched->sched_rq, args->num_rqs);
- if (!sched->sched_rq)
+ sched->rq = kzalloc_obj(*sched->rq);
+ if (!sched->rq)
goto Out_check_own;
- for (i = DRM_SCHED_PRIORITY_KERNEL; i < sched->num_rqs; i++) {
- sched->sched_rq[i] = kzalloc_obj(*sched->sched_rq[i]);
- if (!sched->sched_rq[i])
- goto Out_unroll;
- drm_sched_rq_init(sched, sched->sched_rq[i]);
- }
+ drm_sched_rq_init(sched, sched->rq);
init_waitqueue_head(&sched->job_scheduled);
INIT_LIST_HEAD(&sched->pending_list);
@@ -1174,12 +1121,7 @@ int drm_sched_init(struct drm_gpu_scheduler *sched, const struct drm_sched_init_
sched->ready = true;
return 0;
-Out_unroll:
- for (--i ; i >= DRM_SCHED_PRIORITY_KERNEL; i--)
- kfree(sched->sched_rq[i]);
- kfree(sched->sched_rq);
- sched->sched_rq = NULL;
Out_check_own:
if (sched->own_submit_wq)
destroy_workqueue(sched->submit_wq);
@@ -1215,13 +1157,8 @@ static void drm_sched_cancel_remaining_jobs(struct drm_gpu_scheduler *sched)
*/
void drm_sched_fini(struct drm_gpu_scheduler *sched)
{
- int i;
-
drm_sched_wqueue_stop(sched);
- for (i = DRM_SCHED_PRIORITY_KERNEL; i < sched->num_rqs; i++)
- kfree(sched->sched_rq[i]);
-
/* Wakeup everyone stuck in drm_sched_entity_flush for this scheduler */
wake_up_all(&sched->job_scheduled);
@@ -1235,8 +1172,8 @@ void drm_sched_fini(struct drm_gpu_scheduler *sched)
if (sched->own_submit_wq)
destroy_workqueue(sched->submit_wq);
sched->ready = false;
- kfree(sched->sched_rq);
- sched->sched_rq = NULL;
+ kfree(sched->rq);
+ sched->rq = NULL;
if (!list_empty(&sched->pending_list))
dev_warn(sched->dev, "Tearing down scheduler while jobs are pending!\n");
@@ -1254,35 +1191,28 @@ EXPORT_SYMBOL(drm_sched_fini);
*/
void drm_sched_increase_karma(struct drm_sched_job *bad)
{
- int i;
- struct drm_sched_entity *tmp;
- struct drm_sched_entity *entity;
struct drm_gpu_scheduler *sched = bad->sched;
+ struct drm_sched_entity *entity, *tmp;
+ struct drm_sched_rq *rq = sched->rq;
/* don't change @bad's karma if it's from KERNEL RQ,
* because sometimes GPU hang would cause kernel jobs (like VM updating jobs)
* corrupt but keep in mind that kernel jobs always considered good.
*/
- if (bad->s_priority != DRM_SCHED_PRIORITY_KERNEL) {
- atomic_inc(&bad->karma);
+ if (bad->s_priority == DRM_SCHED_PRIORITY_KERNEL)
+ return;
- for (i = DRM_SCHED_PRIORITY_KERNEL; i < sched->num_rqs; i++) {
- struct drm_sched_rq *rq = sched->sched_rq[i];
+ atomic_inc(&bad->karma);
- spin_lock(&rq->lock);
- list_for_each_entry_safe(entity, tmp, &rq->entities, list) {
- if (bad->s_fence->scheduled.context ==
- entity->fence_context) {
- if (entity->guilty)
- atomic_set(entity->guilty, 1);
- break;
- }
- }
- spin_unlock(&rq->lock);
- if (&entity->list != &rq->entities)
- break;
+ spin_lock(&rq->lock);
+ list_for_each_entry_safe(entity, tmp, &rq->entities, list) {
+ if (bad->s_fence->scheduled.context == entity->fence_context) {
+ if (entity->guilty)
+ atomic_set(entity->guilty, 1);
+ break;
}
}
+ spin_unlock(&rq->lock);
}
EXPORT_SYMBOL(drm_sched_increase_karma);
diff --git a/drivers/gpu/drm/scheduler/sched_rq.c b/drivers/gpu/drm/scheduler/sched_rq.c
index f8bc60026a73..8df040c58b0a 100644
--- a/drivers/gpu/drm/scheduler/sched_rq.c
+++ b/drivers/gpu/drm/scheduler/sched_rq.c
@@ -45,7 +45,7 @@ static void drm_sched_rq_update_prio(struct drm_sched_rq *rq)
rq->head_prio = prio;
}
-static void drm_sched_rq_remove_fifo_locked(struct drm_sched_entity *entity,
+static void drm_sched_rq_remove_tree_locked(struct drm_sched_entity *entity,
struct drm_sched_rq *rq)
{
lockdep_assert_held(&entity->lock);
@@ -58,7 +58,7 @@ static void drm_sched_rq_remove_fifo_locked(struct drm_sched_entity *entity,
}
}
-static void drm_sched_rq_update_fifo_locked(struct drm_sched_entity *entity,
+static void drm_sched_rq_update_tree_locked(struct drm_sched_entity *entity,
struct drm_sched_rq *rq,
ktime_t ts)
{
@@ -70,7 +70,7 @@ static void drm_sched_rq_update_fifo_locked(struct drm_sched_entity *entity,
lockdep_assert_held(&entity->lock);
lockdep_assert_held(&rq->lock);
- drm_sched_rq_remove_fifo_locked(entity, rq);
+ drm_sched_rq_remove_tree_locked(entity, rq);
entity->oldest_job_waiting = ts;
@@ -235,15 +235,9 @@ static ktime_t drm_sched_entity_update_vruntime(struct drm_sched_entity *entity)
return runtime;
}
-static ktime_t drm_sched_entity_get_job_ts(struct drm_sched_entity *entity)
-{
- return drm_sched_entity_update_vruntime(entity);
-}
-
/**
* drm_sched_rq_add_entity - add an entity
* @entity: scheduler entity
- * @ts: submission timestamp
*
* Adds a scheduler entity to the run queue.
*
@@ -251,10 +245,11 @@ static ktime_t drm_sched_entity_get_job_ts(struct drm_sched_entity *entity)
* been stopped and cannot be submitted to.
*/
struct drm_gpu_scheduler *
-drm_sched_rq_add_entity(struct drm_sched_entity *entity, ktime_t ts)
+drm_sched_rq_add_entity(struct drm_sched_entity *entity)
{
struct drm_gpu_scheduler *sched;
struct drm_sched_rq *rq;
+ ktime_t ts;
/* Add the entity to the run queue */
spin_lock(&entity->lock);
@@ -274,15 +269,9 @@ drm_sched_rq_add_entity(struct drm_sched_entity *entity, ktime_t ts)
list_add_tail(&entity->list, &rq->entities);
}
- if (drm_sched_policy == DRM_SCHED_POLICY_FAIR) {
- ts = drm_sched_rq_get_min_vruntime(rq);
- ts = drm_sched_entity_restore_vruntime(entity, ts,
- rq->head_prio);
- } else if (drm_sched_policy == DRM_SCHED_POLICY_RR) {
- ts = entity->rr_ts;
- }
-
- drm_sched_rq_update_fifo_locked(entity, rq, ts);
+ ts = drm_sched_rq_get_min_vruntime(rq);
+ ts = drm_sched_entity_restore_vruntime(entity, ts, rq->head_prio);
+ drm_sched_rq_update_tree_locked(entity, rq, ts);
spin_unlock(&rq->lock);
spin_unlock(&entity->lock);
@@ -310,27 +299,11 @@ void drm_sched_rq_remove_entity(struct drm_sched_rq *rq,
atomic_dec(rq->sched->score);
list_del_init(&entity->list);
- drm_sched_rq_remove_fifo_locked(entity, rq);
+ drm_sched_rq_remove_tree_locked(entity, rq);
spin_unlock(&rq->lock);
}
-static ktime_t
-drm_sched_rq_next_rr_ts(struct drm_sched_rq *rq,
- struct drm_sched_entity *entity)
-{
- ktime_t ts;
-
- lockdep_assert_held(&entity->lock);
- lockdep_assert_held(&rq->lock);
-
- ts = ktime_add_ns(rq->rr_ts, 1);
- entity->rr_ts = ts;
- rq->rr_ts = ts;
-
- return ts;
-}
-
/**
* drm_sched_rq_pop_entity - pops an entity
* @entity: scheduler entity
@@ -353,32 +326,22 @@ void drm_sched_rq_pop_entity(struct drm_sched_entity *entity)
if (next_job) {
ktime_t ts;
- if (drm_sched_policy == DRM_SCHED_POLICY_FAIR)
- ts = drm_sched_entity_get_job_ts(entity);
- else if (drm_sched_policy == DRM_SCHED_POLICY_FIFO)
- ts = next_job->submit_ts;
- else
- ts = drm_sched_rq_next_rr_ts(rq, entity);
-
- drm_sched_rq_update_fifo_locked(entity, rq, ts);
+ ts = drm_sched_entity_update_vruntime(entity);
+ drm_sched_rq_update_tree_locked(entity, rq, ts);
} else {
- drm_sched_rq_remove_fifo_locked(entity, rq);
+ ktime_t min_vruntime;
- if (drm_sched_policy == DRM_SCHED_POLICY_FAIR) {
- ktime_t min_vruntime;
-
- min_vruntime = drm_sched_rq_get_min_vruntime(rq);
- drm_sched_entity_save_vruntime(entity, min_vruntime);
- }
+ drm_sched_rq_remove_tree_locked(entity, rq);
+ min_vruntime = drm_sched_rq_get_min_vruntime(rq);
+ drm_sched_entity_save_vruntime(entity, min_vruntime);
}
spin_unlock(&rq->lock);
spin_unlock(&entity->lock);
}
/**
- * drm_sched_rq_select_entity - Select an entity which provides a job to run
+ * drm_sched_select_entity - Select an entity which provides a job to run
* @sched: the gpu scheduler
- * @rq: scheduler run queue to check.
*
* Find oldest waiting ready entity.
*
@@ -387,9 +350,9 @@ void drm_sched_rq_pop_entity(struct drm_sched_entity *entity)
* its job; return NULL, if no ready entity was found.
*/
struct drm_sched_entity *
-drm_sched_rq_select_entity(struct drm_gpu_scheduler *sched,
- struct drm_sched_rq *rq)
+drm_sched_select_entity(struct drm_gpu_scheduler *sched)
{
+ struct drm_sched_rq *rq = sched->rq;
struct rb_node *rb;
spin_lock(&rq->lock);
diff --git a/include/drm/gpu_scheduler.h b/include/drm/gpu_scheduler.h
index 826de4cbbf2d..ae54e959970c 100644
--- a/include/drm/gpu_scheduler.h
+++ b/include/drm/gpu_scheduler.h
@@ -100,8 +100,7 @@ struct drm_sched_entity {
* @lock:
*
* Lock protecting the run-queue (@rq) to which this entity belongs,
- * @priority, the list of schedulers (@sched_list, @num_sched_list) and
- * the @rr_ts field.
+ * @priority and the list of schedulers (@sched_list, @num_sched_list).
*/
spinlock_t lock;
@@ -154,18 +153,6 @@ struct drm_sched_entity {
*/
enum drm_sched_priority priority;
- /**
- * @rq_priority: Run-queue priority
- */
- enum drm_sched_priority rq_priority;
-
- /**
- * @rr_ts:
- *
- * Fake timestamp of the last popped job from the entity.
- */
- ktime_t rr_ts;
-
/**
* @job_queue: the list of jobs of this entity.
*/
@@ -263,8 +250,7 @@ struct drm_sched_entity {
* struct drm_sched_rq - queue of entities to be scheduled.
*
* @sched: the scheduler to which this rq belongs to.
- * @lock: protects @entities, @rb_tree_root, @rr_ts and @head_prio.
- * @rr_ts: monotonically incrementing fake timestamp for RR mode.
+ * @lock: protects @entities, @rb_tree_root and @head_prio.
* @entities: list of the entities to be scheduled.
* @rb_tree_root: root of time based priority queue of entities for FIFO scheduling
* @head_prio: priority of the top tree element.
@@ -278,7 +264,6 @@ struct drm_sched_rq {
spinlock_t lock;
/* Following members are protected by the @lock: */
- ktime_t rr_ts;
struct list_head entities;
struct rb_root_cached rb_tree_root;
enum drm_sched_priority head_prio;
@@ -364,13 +349,6 @@ struct drm_sched_fence *to_drm_sched_fence(struct dma_fence *f);
* to schedule the job.
*/
struct drm_sched_job {
- /**
- * @submit_ts:
- *
- * When the job was pushed into the entity queue.
- */
- ktime_t submit_ts;
-
/**
* @sched:
*
@@ -574,11 +552,7 @@ struct drm_sched_backend_ops {
* @credit_count: the current credit count of this scheduler
* @timeout: the time after which a job is removed from the scheduler.
* @name: name of the ring for which this scheduler is being used.
- * @num_user_rqs: Number of run-queues. This is at most
- * DRM_SCHED_PRIORITY_COUNT, as there's usually one run-queue per
- * priority, but could be less.
- * @num_rqs: Equal to @num_user_rqs for FIFO and RR and 1 for the FAIR policy.
- * @sched_rq: An allocated array of run-queues of size @num_rqs;
+ * @rq: Scheduler run queue.
* @job_scheduled: once drm_sched_entity_flush() is called the scheduler
* waits on this wait queue until all the scheduled jobs are
* finished.
@@ -610,9 +584,7 @@ struct drm_gpu_scheduler {
atomic_t credit_count;
long timeout;
const char *name;
- u32 num_rqs;
- u32 num_user_rqs;
- struct drm_sched_rq **sched_rq;
+ struct drm_sched_rq *rq;
wait_queue_head_t job_scheduled;
atomic64_t job_id_count;
struct workqueue_struct *submit_wq;
--
2.52.0
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH v7 14/29] drm/sched: Embed run queue singleton into the scheduler
2026-03-06 16:34 [PATCH v7 00/29] Fair(er) DRM scheduler Tvrtko Ursulin
` (12 preceding siblings ...)
2026-03-06 16:34 ` [PATCH v7 13/29] drm/sched: Remove FIFO and RR and simplify to a single run queue Tvrtko Ursulin
@ 2026-03-06 16:34 ` Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 15/29] accel/amdxdna: Remove drm_sched_init_args->num_rqs usage Tvrtko Ursulin
` (15 subsequent siblings)
29 siblings, 0 replies; 32+ messages in thread
From: Tvrtko Ursulin @ 2026-03-06 16:34 UTC (permalink / raw)
To: amd-gfx, dri-devel
Cc: kernel-dev, intel-xe, Danilo Krummrich, Philipp Stanner,
Tvrtko Ursulin, Christian König, Matthew Brost
Now that the run queue to scheduler relationship is always 1:1 we can
embed it (the run queue) directly in the scheduler struct and save on
some allocation error handling code and such.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Philipp Stanner <phasta@kernel.org>
Acked-by: Danilo Krummrich <dakr@kernel.org>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c | 6 +++--
drivers/gpu/drm/amd/amdgpu/amdgpu_job.c | 6 +++--
drivers/gpu/drm/amd/amdgpu/amdgpu_job.h | 5 +++-
drivers/gpu/drm/amd/amdgpu/amdgpu_trace.h | 8 ++++--
drivers/gpu/drm/amd/amdgpu/amdgpu_vm_sdma.c | 8 +++---
drivers/gpu/drm/amd/amdgpu/amdgpu_xcp.c | 8 +++---
drivers/gpu/drm/scheduler/sched_entity.c | 29 ++++++++-------------
drivers/gpu/drm/scheduler/sched_fence.c | 2 +-
drivers/gpu/drm/scheduler/sched_internal.h | 3 +--
drivers/gpu/drm/scheduler/sched_main.c | 27 +++----------------
drivers/gpu/drm/scheduler/sched_rq.c | 16 ++++++------
include/drm/gpu_scheduler.h | 5 +---
12 files changed, 51 insertions(+), 72 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
index 24e4b4fc9156..8719aa0adad8 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
@@ -1108,7 +1108,8 @@ static int amdgpu_cs_vm_handling(struct amdgpu_cs_parser *p)
if (p->gang_size > 1 && !adev->vm_manager.concurrent_flush) {
for (i = 0; i < p->gang_size; ++i) {
struct drm_sched_entity *entity = p->entities[i];
- struct drm_gpu_scheduler *sched = entity->rq->sched;
+ struct drm_gpu_scheduler *sched =
+ container_of(entity->rq, typeof(*sched), rq);
struct amdgpu_ring *ring = to_amdgpu_ring(sched);
if (amdgpu_vmid_uses_reserved(vm, ring->vm_hub))
@@ -1239,7 +1240,8 @@ static int amdgpu_cs_sync_rings(struct amdgpu_cs_parser *p)
return r;
}
- sched = p->gang_leader->base.entity->rq->sched;
+ sched = container_of(p->gang_leader->base.entity->rq, typeof(*sched),
+ rq);
while ((fence = amdgpu_sync_get_fence(&p->sync))) {
struct drm_sched_fence *s_fence = to_drm_sched_fence(fence);
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
index 7d6ff0b6ca4e..d6ff3fbabd88 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
@@ -390,7 +390,9 @@ static struct dma_fence *
amdgpu_job_prepare_job(struct drm_sched_job *sched_job,
struct drm_sched_entity *s_entity)
{
- struct amdgpu_ring *ring = to_amdgpu_ring(s_entity->rq->sched);
+ struct drm_gpu_scheduler *sched =
+ container_of(s_entity->rq, typeof(*sched), rq);
+ struct amdgpu_ring *ring = to_amdgpu_ring(sched);
struct amdgpu_job *job = to_amdgpu_job(sched_job);
struct dma_fence *fence;
int r;
@@ -483,7 +485,7 @@ drm_sched_entity_queue_pop(struct drm_sched_entity *entity)
void amdgpu_job_stop_all_jobs_on_sched(struct drm_gpu_scheduler *sched)
{
- struct drm_sched_rq *rq = sched->rq;
+ struct drm_sched_rq *rq = &sched->rq;
struct drm_sched_entity *s_entity;
struct drm_sched_job *s_job;
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.h
index 56a88e14a044..e70a1117b812 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.h
@@ -107,7 +107,10 @@ struct amdgpu_job {
static inline struct amdgpu_ring *amdgpu_job_ring(struct amdgpu_job *job)
{
- return to_amdgpu_ring(job->base.entity->rq->sched);
+ struct drm_gpu_scheduler *sched =
+ container_of(job->base.entity->rq, typeof(*sched), rq);
+
+ return to_amdgpu_ring(sched);
}
int amdgpu_job_alloc(struct amdgpu_device *adev, struct amdgpu_vm *vm,
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_trace.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_trace.h
index d13e64a69e25..85724ec6aaf8 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_trace.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_trace.h
@@ -145,6 +145,7 @@ TRACE_EVENT(amdgpu_cs,
struct amdgpu_ib *ib),
TP_ARGS(p, job, ib),
TP_STRUCT__entry(
+ __field(struct drm_gpu_scheduler *, sched)
__field(struct amdgpu_bo_list *, bo_list)
__field(u32, ring)
__field(u32, dw)
@@ -152,11 +153,14 @@ TRACE_EVENT(amdgpu_cs,
),
TP_fast_assign(
+ __entry->sched = container_of(job->base.entity->rq,
+ typeof(*__entry->sched),
+ rq);
__entry->bo_list = p->bo_list;
- __entry->ring = to_amdgpu_ring(job->base.entity->rq->sched)->idx;
+ __entry->ring = to_amdgpu_ring(__entry->sched)->idx;
__entry->dw = ib->length_dw;
__entry->fences = amdgpu_fence_count_emitted(
- to_amdgpu_ring(job->base.entity->rq->sched));
+ to_amdgpu_ring(__entry->sched));
),
TP_printk("bo_list=%p, ring=%u, dw=%u, fences=%u",
__entry->bo_list, __entry->ring, __entry->dw,
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_sdma.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_sdma.c
index 36805dcfa159..4ccd2e769799 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_sdma.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_sdma.c
@@ -106,13 +106,13 @@ static int amdgpu_vm_sdma_prepare(struct amdgpu_vm_update_params *p,
static int amdgpu_vm_sdma_commit(struct amdgpu_vm_update_params *p,
struct dma_fence **fence)
{
+ struct drm_gpu_scheduler *sched =
+ container_of(p->vm->delayed.rq, typeof(*sched), rq);
+ struct amdgpu_ring *ring =
+ container_of(sched, struct amdgpu_ring, sched);
struct amdgpu_ib *ib = p->job->ibs;
- struct amdgpu_ring *ring;
struct dma_fence *f;
- ring = container_of(p->vm->delayed.rq->sched, struct amdgpu_ring,
- sched);
-
WARN_ON(ib->length_dw == 0);
amdgpu_ring_pad_ib(ring, ib);
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_xcp.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_xcp.c
index cc5f4e01e38f..fee77af5045f 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_xcp.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_xcp.c
@@ -465,15 +465,15 @@ int amdgpu_xcp_open_device(struct amdgpu_device *adev,
void amdgpu_xcp_release_sched(struct amdgpu_device *adev,
struct amdgpu_ctx_entity *entity)
{
- struct drm_gpu_scheduler *sched;
- struct amdgpu_ring *ring;
+ struct drm_gpu_scheduler *sched =
+ container_of(entity->entity.rq, typeof(*sched), rq);
if (!adev->xcp_mgr)
return;
- sched = entity->entity.rq->sched;
if (drm_sched_wqueue_ready(sched)) {
- ring = to_amdgpu_ring(entity->entity.rq->sched);
+ struct amdgpu_ring *ring = to_amdgpu_ring(sched);
+
atomic_dec(&adev->xcp_mgr->xcp[ring->xcp_id].ref_cnt);
}
}
diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.c
index 713ae46f7bbd..61a4818cc87b 100644
--- a/drivers/gpu/drm/scheduler/sched_entity.c
+++ b/drivers/gpu/drm/scheduler/sched_entity.c
@@ -136,19 +136,9 @@ int drm_sched_entity_init(struct drm_sched_entity *entity,
entity->last_user = current->group_leader;
entity->num_sched_list = num_sched_list;
entity->sched_list = num_sched_list > 1 ? sched_list : NULL;
+ entity->rq = &sched_list[0]->rq;
RCU_INIT_POINTER(entity->last_scheduled, NULL);
RB_CLEAR_NODE(&entity->rb_tree_node);
-
- if (!sched_list[0]->rq) {
- /* Since every entry covered by num_sched_list
- * should be non-NULL and therefore we warn drivers
- * not to do this and to fix their DRM calling order.
- */
- pr_warn("%s: called with uninitialized scheduler\n", __func__);
- } else {
- entity->rq = sched_list[0]->rq;
- }
-
init_completion(&entity->entity_idle);
/* We start in an idle state. */
@@ -338,7 +328,7 @@ long drm_sched_entity_flush(struct drm_sched_entity *entity, long timeout)
if (!entity->rq)
return 0;
- sched = entity->rq->sched;
+ sched = container_of(entity->rq, typeof(*sched), rq);
/*
* The client will not queue more jobs during this fini - consume
* existing queued ones, or discard them on SIGKILL.
@@ -419,10 +409,12 @@ static void drm_sched_entity_wakeup(struct dma_fence *f,
{
struct drm_sched_entity *entity =
container_of(cb, struct drm_sched_entity, cb);
+ struct drm_gpu_scheduler *sched =
+ container_of(entity->rq, typeof(*sched), rq);
entity->dependency = NULL;
dma_fence_put(f);
- drm_sched_wakeup(entity->rq->sched);
+ drm_sched_wakeup(sched);
}
/**
@@ -449,7 +441,8 @@ EXPORT_SYMBOL(drm_sched_entity_set_priority);
static bool drm_sched_entity_add_dependency_cb(struct drm_sched_entity *entity,
struct drm_sched_job *sched_job)
{
- struct drm_gpu_scheduler *sched = entity->rq->sched;
+ struct drm_gpu_scheduler *sched =
+ container_of(entity->rq, typeof(*sched), rq);
struct dma_fence *fence = entity->dependency;
struct drm_sched_fence *s_fence;
@@ -583,7 +576,7 @@ void drm_sched_entity_select_rq(struct drm_sched_entity *entity)
spin_lock(&entity->lock);
sched = drm_sched_pick_best(entity->sched_list, entity->num_sched_list);
- rq = sched ? sched->rq : NULL;
+ rq = sched ? &sched->rq : NULL;
if (rq != entity->rq) {
drm_sched_rq_remove_entity(entity->rq, entity);
entity->rq = rq;
@@ -607,6 +600,8 @@ void drm_sched_entity_select_rq(struct drm_sched_entity *entity)
void drm_sched_entity_push_job(struct drm_sched_job *sched_job)
{
struct drm_sched_entity *entity = sched_job->entity;
+ struct drm_gpu_scheduler *sched =
+ container_of(entity->rq, typeof(*sched), rq);
bool first;
trace_drm_sched_job_queue(sched_job, entity);
@@ -618,7 +613,7 @@ void drm_sched_entity_push_job(struct drm_sched_job *sched_job)
xa_for_each(&sched_job->dependencies, index, entry)
trace_drm_sched_job_add_dep(sched_job, entry);
}
- atomic_inc(entity->rq->sched->score);
+ atomic_inc(sched->score);
WRITE_ONCE(entity->last_user, current->group_leader);
/*
@@ -629,8 +624,6 @@ void drm_sched_entity_push_job(struct drm_sched_job *sched_job)
/* first job wakes up scheduler */
if (first) {
- struct drm_gpu_scheduler *sched;
-
sched = drm_sched_rq_add_entity(entity);
if (sched)
drm_sched_wakeup(sched);
diff --git a/drivers/gpu/drm/scheduler/sched_fence.c b/drivers/gpu/drm/scheduler/sched_fence.c
index 096fe28aa9c9..85ee3d694dc9 100644
--- a/drivers/gpu/drm/scheduler/sched_fence.c
+++ b/drivers/gpu/drm/scheduler/sched_fence.c
@@ -227,7 +227,7 @@ void drm_sched_fence_init(struct drm_sched_fence *fence,
{
unsigned seq;
- fence->sched = entity->rq->sched;
+ fence->sched = container_of(entity->rq, typeof(*fence->sched), rq);
seq = atomic_inc_return(&entity->fence_seq);
dma_fence_init(&fence->scheduled, &drm_sched_fence_ops_scheduled,
&fence->lock, entity->fence_context, seq);
diff --git a/drivers/gpu/drm/scheduler/sched_internal.h b/drivers/gpu/drm/scheduler/sched_internal.h
index 520a421cbf8d..af43a350356e 100644
--- a/drivers/gpu/drm/scheduler/sched_internal.h
+++ b/drivers/gpu/drm/scheduler/sched_internal.h
@@ -35,8 +35,7 @@ bool drm_sched_can_queue(struct drm_gpu_scheduler *sched,
struct drm_sched_entity *entity);
void drm_sched_wakeup(struct drm_gpu_scheduler *sched);
-void drm_sched_rq_init(struct drm_gpu_scheduler *sched,
- struct drm_sched_rq *rq);
+void drm_sched_rq_init(struct drm_sched_rq *rq);
struct drm_gpu_scheduler *
drm_sched_rq_add_entity(struct drm_sched_entity *entity);
diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
index 79e44ccefdc9..818d3d4434b5 100644
--- a/drivers/gpu/drm/scheduler/sched_main.c
+++ b/drivers/gpu/drm/scheduler/sched_main.c
@@ -648,7 +648,7 @@ void drm_sched_job_arm(struct drm_sched_job *job)
BUG_ON(!entity);
drm_sched_entity_select_rq(entity);
- sched = entity->rq->sched;
+ sched = container_of(entity->rq, typeof(*sched), rq);
job->sched = sched;
job->s_priority = entity->priority;
@@ -1081,15 +1081,6 @@ int drm_sched_init(struct drm_gpu_scheduler *sched, const struct drm_sched_init_
sched->score = args->score ? args->score : &sched->_score;
sched->dev = args->dev;
- if (sched->rq) {
- /* Not an error, but warn anyway so drivers can
- * fine-tune their DRM calling order, and return all
- * is good.
- */
- dev_warn(sched->dev, "%s: scheduler already initialized!\n", __func__);
- return 0;
- }
-
if (args->submit_wq) {
sched->submit_wq = args->submit_wq;
sched->own_submit_wq = false;
@@ -1101,11 +1092,7 @@ int drm_sched_init(struct drm_gpu_scheduler *sched, const struct drm_sched_init_
sched->own_submit_wq = true;
}
- sched->rq = kzalloc_obj(*sched->rq);
- if (!sched->rq)
- goto Out_check_own;
-
- drm_sched_rq_init(sched, sched->rq);
+ drm_sched_rq_init(&sched->rq);
init_waitqueue_head(&sched->job_scheduled);
INIT_LIST_HEAD(&sched->pending_list);
@@ -1121,12 +1108,6 @@ int drm_sched_init(struct drm_gpu_scheduler *sched, const struct drm_sched_init_
sched->ready = true;
return 0;
-
-Out_check_own:
- if (sched->own_submit_wq)
- destroy_workqueue(sched->submit_wq);
- dev_err(sched->dev, "%s: Failed to setup GPU scheduler--out of memory\n", __func__);
- return -ENOMEM;
}
EXPORT_SYMBOL(drm_sched_init);
@@ -1172,8 +1153,6 @@ void drm_sched_fini(struct drm_gpu_scheduler *sched)
if (sched->own_submit_wq)
destroy_workqueue(sched->submit_wq);
sched->ready = false;
- kfree(sched->rq);
- sched->rq = NULL;
if (!list_empty(&sched->pending_list))
dev_warn(sched->dev, "Tearing down scheduler while jobs are pending!\n");
@@ -1193,7 +1172,7 @@ void drm_sched_increase_karma(struct drm_sched_job *bad)
{
struct drm_gpu_scheduler *sched = bad->sched;
struct drm_sched_entity *entity, *tmp;
- struct drm_sched_rq *rq = sched->rq;
+ struct drm_sched_rq *rq = &sched->rq;
/* don't change @bad's karma if it's from KERNEL RQ,
* because sometimes GPU hang would cause kernel jobs (like VM updating jobs)
diff --git a/drivers/gpu/drm/scheduler/sched_rq.c b/drivers/gpu/drm/scheduler/sched_rq.c
index 8df040c58b0a..f55fc2de0270 100644
--- a/drivers/gpu/drm/scheduler/sched_rq.c
+++ b/drivers/gpu/drm/scheduler/sched_rq.c
@@ -81,18 +81,15 @@ static void drm_sched_rq_update_tree_locked(struct drm_sched_entity *entity,
/**
* drm_sched_rq_init - initialize a given run queue struct
- * @sched: scheduler instance to associate with this run queue
* @rq: scheduler run queue
*
* Initializes a scheduler runqueue.
*/
-void drm_sched_rq_init(struct drm_gpu_scheduler *sched,
- struct drm_sched_rq *rq)
+void drm_sched_rq_init(struct drm_sched_rq *rq)
{
spin_lock_init(&rq->lock);
INIT_LIST_HEAD(&rq->entities);
rq->rb_tree_root = RB_ROOT_CACHED;
- rq->sched = sched;
rq->head_prio = DRM_SCHED_PRIORITY_INVALID;
}
@@ -161,7 +158,8 @@ drm_sched_entity_restore_vruntime(struct drm_sched_entity *entity,
enum drm_sched_priority rq_prio)
{
struct drm_sched_entity_stats *stats = entity->stats;
- struct drm_gpu_scheduler *sched = entity->rq->sched;
+ struct drm_gpu_scheduler *sched =
+ container_of(entity->rq, typeof(*sched), rq);
enum drm_sched_priority prio = entity->priority;
unsigned long avg_us, sched_avg_us;
ktime_t vruntime;
@@ -261,8 +259,8 @@ drm_sched_rq_add_entity(struct drm_sched_entity *entity)
}
rq = entity->rq;
+ sched = container_of(rq, typeof(*sched), rq);
spin_lock(&rq->lock);
- sched = rq->sched;
if (list_empty(&entity->list)) {
atomic_inc(sched->score);
@@ -289,6 +287,8 @@ drm_sched_rq_add_entity(struct drm_sched_entity *entity)
void drm_sched_rq_remove_entity(struct drm_sched_rq *rq,
struct drm_sched_entity *entity)
{
+ struct drm_gpu_scheduler *sched = container_of(rq, typeof(*sched), rq);
+
lockdep_assert_held(&entity->lock);
if (list_empty(&entity->list))
@@ -296,7 +296,7 @@ void drm_sched_rq_remove_entity(struct drm_sched_rq *rq,
spin_lock(&rq->lock);
- atomic_dec(rq->sched->score);
+ atomic_dec(sched->score);
list_del_init(&entity->list);
drm_sched_rq_remove_tree_locked(entity, rq);
@@ -352,7 +352,7 @@ void drm_sched_rq_pop_entity(struct drm_sched_entity *entity)
struct drm_sched_entity *
drm_sched_select_entity(struct drm_gpu_scheduler *sched)
{
- struct drm_sched_rq *rq = sched->rq;
+ struct drm_sched_rq *rq = &sched->rq;
struct rb_node *rb;
spin_lock(&rq->lock);
diff --git a/include/drm/gpu_scheduler.h b/include/drm/gpu_scheduler.h
index ae54e959970c..cea2ee956422 100644
--- a/include/drm/gpu_scheduler.h
+++ b/include/drm/gpu_scheduler.h
@@ -249,7 +249,6 @@ struct drm_sched_entity {
/**
* struct drm_sched_rq - queue of entities to be scheduled.
*
- * @sched: the scheduler to which this rq belongs to.
* @lock: protects @entities, @rb_tree_root and @head_prio.
* @entities: list of the entities to be scheduled.
* @rb_tree_root: root of time based priority queue of entities for FIFO scheduling
@@ -260,8 +259,6 @@ struct drm_sched_entity {
* the next entity to emit commands from.
*/
struct drm_sched_rq {
- struct drm_gpu_scheduler *sched;
-
spinlock_t lock;
/* Following members are protected by the @lock: */
struct list_head entities;
@@ -584,7 +581,7 @@ struct drm_gpu_scheduler {
atomic_t credit_count;
long timeout;
const char *name;
- struct drm_sched_rq *rq;
+ struct drm_sched_rq rq;
wait_queue_head_t job_scheduled;
atomic64_t job_id_count;
struct workqueue_struct *submit_wq;
--
2.52.0
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH v7 15/29] accel/amdxdna: Remove drm_sched_init_args->num_rqs usage
2026-03-06 16:34 [PATCH v7 00/29] Fair(er) DRM scheduler Tvrtko Ursulin
` (13 preceding siblings ...)
2026-03-06 16:34 ` [PATCH v7 14/29] drm/sched: Embed run queue singleton into the scheduler Tvrtko Ursulin
@ 2026-03-06 16:34 ` Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 16/29] accel/rocket: " Tvrtko Ursulin
` (14 subsequent siblings)
29 siblings, 0 replies; 32+ messages in thread
From: Tvrtko Ursulin @ 2026-03-06 16:34 UTC (permalink / raw)
To: amd-gfx, dri-devel
Cc: kernel-dev, intel-xe, Danilo Krummrich, Philipp Stanner,
Tvrtko Ursulin, Min Ma, Lizhi Hou, Oded Gabbay
Remove member no longer used by the scheduler core.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Cc: Min Ma <mamin506@gmail.com>
Cc: Lizhi Hou <lizhi.hou@amd.com>
Cc: Oded Gabbay <ogabbay@kernel.org>
Reviewed-by: Lizhi Hou <lizhi.hou@amd.com>
---
drivers/accel/amdxdna/aie2_ctx.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/drivers/accel/amdxdna/aie2_ctx.c b/drivers/accel/amdxdna/aie2_ctx.c
index afee5e667f77..9d4791fb6c45 100644
--- a/drivers/accel/amdxdna/aie2_ctx.c
+++ b/drivers/accel/amdxdna/aie2_ctx.c
@@ -545,7 +545,6 @@ int aie2_hwctx_init(struct amdxdna_hwctx *hwctx)
struct amdxdna_dev *xdna = client->xdna;
const struct drm_sched_init_args args = {
.ops = &sched_ops,
- .num_rqs = DRM_SCHED_PRIORITY_COUNT,
.credit_limit = HWCTX_MAX_CMDS,
.timeout = msecs_to_jiffies(HWCTX_MAX_TIMEOUT),
.name = "amdxdna_js",
--
2.52.0
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH v7 16/29] accel/rocket: Remove drm_sched_init_args->num_rqs usage
2026-03-06 16:34 [PATCH v7 00/29] Fair(er) DRM scheduler Tvrtko Ursulin
` (14 preceding siblings ...)
2026-03-06 16:34 ` [PATCH v7 15/29] accel/amdxdna: Remove drm_sched_init_args->num_rqs usage Tvrtko Ursulin
@ 2026-03-06 16:34 ` Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 17/29] accel/ethosu: " Tvrtko Ursulin
` (13 subsequent siblings)
29 siblings, 0 replies; 32+ messages in thread
From: Tvrtko Ursulin @ 2026-03-06 16:34 UTC (permalink / raw)
To: amd-gfx, dri-devel
Cc: kernel-dev, intel-xe, Danilo Krummrich, Philipp Stanner,
Tvrtko Ursulin, Tomeu Vizoso, Oded Gabbay
Remove member no longer used by the scheduler core.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Cc: Tomeu Vizoso <tomeu@tomeuvizoso.net>
Cc: Oded Gabbay <ogabbay@kernel.org>
Reviewed-by: Tomeu Vizoso <tomeu@tomeuvizoso.net>
---
drivers/accel/rocket/rocket_job.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/drivers/accel/rocket/rocket_job.c b/drivers/accel/rocket/rocket_job.c
index ac51bff39833..2f1861f960cc 100644
--- a/drivers/accel/rocket/rocket_job.c
+++ b/drivers/accel/rocket/rocket_job.c
@@ -437,7 +437,6 @@ int rocket_job_init(struct rocket_core *core)
{
struct drm_sched_init_args args = {
.ops = &rocket_sched_ops,
- .num_rqs = DRM_SCHED_PRIORITY_COUNT,
.credit_limit = 1,
.timeout = msecs_to_jiffies(JOB_TIMEOUT_MS),
.name = dev_name(core->dev),
--
2.52.0
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH v7 17/29] accel/ethosu: Remove drm_sched_init_args->num_rqs usage
2026-03-06 16:34 [PATCH v7 00/29] Fair(er) DRM scheduler Tvrtko Ursulin
` (15 preceding siblings ...)
2026-03-06 16:34 ` [PATCH v7 16/29] accel/rocket: " Tvrtko Ursulin
@ 2026-03-06 16:34 ` Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 18/29] drm/amdgpu: " Tvrtko Ursulin
` (12 subsequent siblings)
29 siblings, 0 replies; 32+ messages in thread
From: Tvrtko Ursulin @ 2026-03-06 16:34 UTC (permalink / raw)
To: amd-gfx, dri-devel
Cc: kernel-dev, intel-xe, Danilo Krummrich, Philipp Stanner,
Tvrtko Ursulin, Rob Herring (Arm), Tomeu Vizoso, Oded Gabbay
Remove member no longer used by the scheduler core.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Cc: "Rob Herring (Arm)" <robh@kernel.org>
Cc: Tomeu Vizoso <tomeu@tomeuvizoso.net>
Cc: Oded Gabbay <ogabbay@kernel.org>
Acked-by: Rob Herring (Arm) <robh@kernel.org>
---
drivers/accel/ethosu/ethosu_job.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/drivers/accel/ethosu/ethosu_job.c b/drivers/accel/ethosu/ethosu_job.c
index ec85f4156744..418463c03bfb 100644
--- a/drivers/accel/ethosu/ethosu_job.c
+++ b/drivers/accel/ethosu/ethosu_job.c
@@ -296,7 +296,6 @@ int ethosu_job_init(struct ethosu_device *edev)
struct device *dev = edev->base.dev;
struct drm_sched_init_args args = {
.ops = ðosu_sched_ops,
- .num_rqs = DRM_SCHED_PRIORITY_COUNT,
.credit_limit = 1,
.timeout = msecs_to_jiffies(JOB_TIMEOUT_MS),
.name = dev_name(dev),
--
2.52.0
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH v7 18/29] drm/amdgpu: Remove drm_sched_init_args->num_rqs usage
2026-03-06 16:34 [PATCH v7 00/29] Fair(er) DRM scheduler Tvrtko Ursulin
` (16 preceding siblings ...)
2026-03-06 16:34 ` [PATCH v7 17/29] accel/ethosu: " Tvrtko Ursulin
@ 2026-03-06 16:34 ` Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 19/29] drm/etnaviv: " Tvrtko Ursulin
` (11 subsequent siblings)
29 siblings, 0 replies; 32+ messages in thread
From: Tvrtko Ursulin @ 2026-03-06 16:34 UTC (permalink / raw)
To: amd-gfx, dri-devel
Cc: kernel-dev, intel-xe, Danilo Krummrich, Philipp Stanner,
Tvrtko Ursulin, Alex Deucher, Christian König
Remove member no longer used by the scheduler core.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: amd-gfx@lists.freedesktop.org
---
drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index 3e19b51a2763..5a51bd9087e4 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -2917,7 +2917,6 @@ static int amdgpu_device_init_schedulers(struct amdgpu_device *adev)
{
struct drm_sched_init_args args = {
.ops = &amdgpu_sched_ops,
- .num_rqs = DRM_SCHED_PRIORITY_COUNT,
.timeout_wq = adev->reset_domain->wq,
.dev = adev->dev,
};
--
2.52.0
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH v7 19/29] drm/etnaviv: Remove drm_sched_init_args->num_rqs usage
2026-03-06 16:34 [PATCH v7 00/29] Fair(er) DRM scheduler Tvrtko Ursulin
` (17 preceding siblings ...)
2026-03-06 16:34 ` [PATCH v7 18/29] drm/amdgpu: " Tvrtko Ursulin
@ 2026-03-06 16:34 ` Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 20/29] drm/imagination: " Tvrtko Ursulin
` (10 subsequent siblings)
29 siblings, 0 replies; 32+ messages in thread
From: Tvrtko Ursulin @ 2026-03-06 16:34 UTC (permalink / raw)
To: amd-gfx, dri-devel
Cc: kernel-dev, intel-xe, Danilo Krummrich, Philipp Stanner,
Tvrtko Ursulin, Lucas Stach, Russell King, Christian Gmeiner,
etnaviv, Christian Gmeiner
Remove member no longer used by the scheduler core.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Russell King <linux+etnaviv@armlinux.org.uk>
Cc: Christian Gmeiner <christian.gmeiner@gmail.com>
Cc: etnaviv@lists.freedesktop.org
Reviewed-by: Christian Gmeiner <cgmeiner@igalia.com>
---
drivers/gpu/drm/etnaviv/etnaviv_sched.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/drivers/gpu/drm/etnaviv/etnaviv_sched.c b/drivers/gpu/drm/etnaviv/etnaviv_sched.c
index df4232d7e135..63f672536516 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_sched.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_sched.c
@@ -142,7 +142,6 @@ int etnaviv_sched_init(struct etnaviv_gpu *gpu)
{
const struct drm_sched_init_args args = {
.ops = &etnaviv_sched_ops,
- .num_rqs = DRM_SCHED_PRIORITY_COUNT,
.credit_limit = etnaviv_hw_jobs_limit,
.hang_limit = etnaviv_job_hang_limit,
.timeout = msecs_to_jiffies(500),
--
2.52.0
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH v7 20/29] drm/imagination: Remove drm_sched_init_args->num_rqs usage
2026-03-06 16:34 [PATCH v7 00/29] Fair(er) DRM scheduler Tvrtko Ursulin
` (18 preceding siblings ...)
2026-03-06 16:34 ` [PATCH v7 19/29] drm/etnaviv: " Tvrtko Ursulin
@ 2026-03-06 16:34 ` Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 21/29] drm/lima: " Tvrtko Ursulin
` (9 subsequent siblings)
29 siblings, 0 replies; 32+ messages in thread
From: Tvrtko Ursulin @ 2026-03-06 16:34 UTC (permalink / raw)
To: amd-gfx, dri-devel
Cc: kernel-dev, intel-xe, Danilo Krummrich, Philipp Stanner,
Tvrtko Ursulin, Frank Binns, Matt Coster
Remove member no longer used by the scheduler core.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Cc: Frank Binns <frank.binns@imgtec.com>
Cc: Matt Coster <matt.coster@imgtec.com>
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Matt Coster <matt.coster@imgtec.com>
---
drivers/gpu/drm/imagination/pvr_queue.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/drivers/gpu/drm/imagination/pvr_queue.c b/drivers/gpu/drm/imagination/pvr_queue.c
index dd88949f6194..2b8ec4f87799 100644
--- a/drivers/gpu/drm/imagination/pvr_queue.c
+++ b/drivers/gpu/drm/imagination/pvr_queue.c
@@ -1228,7 +1228,6 @@ struct pvr_queue *pvr_queue_create(struct pvr_context *ctx,
const struct drm_sched_init_args sched_args = {
.ops = &pvr_queue_sched_ops,
.submit_wq = pvr_dev->sched_wq,
- .num_rqs = 1,
.credit_limit = 64 * 1024,
.hang_limit = 1,
.timeout = msecs_to_jiffies(500),
--
2.52.0
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH v7 21/29] drm/lima: Remove drm_sched_init_args->num_rqs usage
2026-03-06 16:34 [PATCH v7 00/29] Fair(er) DRM scheduler Tvrtko Ursulin
` (19 preceding siblings ...)
2026-03-06 16:34 ` [PATCH v7 20/29] drm/imagination: " Tvrtko Ursulin
@ 2026-03-06 16:34 ` Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 22/29] drm/msm: " Tvrtko Ursulin
` (8 subsequent siblings)
29 siblings, 0 replies; 32+ messages in thread
From: Tvrtko Ursulin @ 2026-03-06 16:34 UTC (permalink / raw)
To: amd-gfx, dri-devel
Cc: kernel-dev, intel-xe, Danilo Krummrich, Philipp Stanner,
Tvrtko Ursulin, Qiang Yu, lima
Remove member no longer used by the scheduler core.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Cc: Qiang Yu <yuq825@gmail.com>
Cc: lima@lists.freedesktop.org
Reviewed-by: Qiang Yu <yuq825@gmail.com>
---
drivers/gpu/drm/lima/lima_sched.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/drivers/gpu/drm/lima/lima_sched.c b/drivers/gpu/drm/lima/lima_sched.c
index 9a1e6b9ecbe5..0a01213c4878 100644
--- a/drivers/gpu/drm/lima/lima_sched.c
+++ b/drivers/gpu/drm/lima/lima_sched.c
@@ -521,7 +521,6 @@ int lima_sched_pipe_init(struct lima_sched_pipe *pipe, const char *name)
lima_sched_timeout_ms : 10000;
const struct drm_sched_init_args args = {
.ops = &lima_sched_ops,
- .num_rqs = DRM_SCHED_PRIORITY_COUNT,
.credit_limit = 1,
.hang_limit = lima_job_hang_limit,
.timeout = msecs_to_jiffies(timeout),
--
2.52.0
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH v7 22/29] drm/msm: Remove drm_sched_init_args->num_rqs usage
2026-03-06 16:34 [PATCH v7 00/29] Fair(er) DRM scheduler Tvrtko Ursulin
` (20 preceding siblings ...)
2026-03-06 16:34 ` [PATCH v7 21/29] drm/lima: " Tvrtko Ursulin
@ 2026-03-06 16:34 ` Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 23/29] drm/nouveau: " Tvrtko Ursulin
` (7 subsequent siblings)
29 siblings, 0 replies; 32+ messages in thread
From: Tvrtko Ursulin @ 2026-03-06 16:34 UTC (permalink / raw)
To: amd-gfx, dri-devel
Cc: kernel-dev, intel-xe, Danilo Krummrich, Philipp Stanner,
Tvrtko Ursulin, Rob Clark, linux-arm-msm, freedreno
Remove member no longer used by the scheduler core.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Cc: Rob Clark <robin.clark@oss.qualcomm.com>
Cc: linux-arm-msm@vger.kernel.org
Cc: freedreno@lists.freedesktop.org
---
drivers/gpu/drm/msm/msm_gem_vma.c | 1 -
drivers/gpu/drm/msm/msm_ringbuffer.c | 1 -
2 files changed, 2 deletions(-)
diff --git a/drivers/gpu/drm/msm/msm_gem_vma.c b/drivers/gpu/drm/msm/msm_gem_vma.c
index adf88cf8f41a..086f72744312 100644
--- a/drivers/gpu/drm/msm/msm_gem_vma.c
+++ b/drivers/gpu/drm/msm/msm_gem_vma.c
@@ -832,7 +832,6 @@ msm_gem_vm_create(struct drm_device *drm, struct msm_mmu *mmu, const char *name,
if (!managed) {
struct drm_sched_init_args args = {
.ops = &msm_vm_bind_ops,
- .num_rqs = 1,
.credit_limit = 1,
.timeout = MAX_SCHEDULE_TIMEOUT,
.name = "msm-vm-bind",
diff --git a/drivers/gpu/drm/msm/msm_ringbuffer.c b/drivers/gpu/drm/msm/msm_ringbuffer.c
index 30ddb5351e98..a7dafa7ab4b1 100644
--- a/drivers/gpu/drm/msm/msm_ringbuffer.c
+++ b/drivers/gpu/drm/msm/msm_ringbuffer.c
@@ -67,7 +67,6 @@ struct msm_ringbuffer *msm_ringbuffer_new(struct msm_gpu *gpu, int id,
{
struct drm_sched_init_args args = {
.ops = &msm_sched_ops,
- .num_rqs = DRM_SCHED_PRIORITY_COUNT,
.credit_limit = num_hw_submissions,
.timeout = MAX_SCHEDULE_TIMEOUT,
.dev = gpu->dev->dev,
--
2.52.0
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH v7 23/29] drm/nouveau: Remove drm_sched_init_args->num_rqs usage
2026-03-06 16:34 [PATCH v7 00/29] Fair(er) DRM scheduler Tvrtko Ursulin
` (21 preceding siblings ...)
2026-03-06 16:34 ` [PATCH v7 22/29] drm/msm: " Tvrtko Ursulin
@ 2026-03-06 16:34 ` Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 24/29] drm/panfrost: " Tvrtko Ursulin
` (6 subsequent siblings)
29 siblings, 0 replies; 32+ messages in thread
From: Tvrtko Ursulin @ 2026-03-06 16:34 UTC (permalink / raw)
To: amd-gfx, dri-devel
Cc: kernel-dev, intel-xe, Danilo Krummrich, Philipp Stanner,
Tvrtko Ursulin, Lyude Paul, nouveau
Remove member no longer used by the scheduler core.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Cc: Lyude Paul <lyude@redhat.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: nouveau@lists.freedesktop.org
Reviewed-by: Lyude Paul <lyude@redhat.com>
Acked-by: Danilo Krummrich <dakr@kernel.org>
---
drivers/gpu/drm/nouveau/nouveau_sched.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/drivers/gpu/drm/nouveau/nouveau_sched.c b/drivers/gpu/drm/nouveau/nouveau_sched.c
index 5546be488795..179edf90a531 100644
--- a/drivers/gpu/drm/nouveau/nouveau_sched.c
+++ b/drivers/gpu/drm/nouveau/nouveau_sched.c
@@ -405,7 +405,6 @@ nouveau_sched_init(struct nouveau_sched *sched, struct nouveau_drm *drm,
struct drm_sched_entity *entity = &sched->entity;
struct drm_sched_init_args args = {
.ops = &nouveau_sched_ops,
- .num_rqs = DRM_SCHED_PRIORITY_COUNT,
.credit_limit = credit_limit,
.timeout = msecs_to_jiffies(NOUVEAU_SCHED_JOB_TIMEOUT_MS),
.name = "nouveau_sched",
--
2.52.0
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH v7 24/29] drm/panfrost: Remove drm_sched_init_args->num_rqs usage
2026-03-06 16:34 [PATCH v7 00/29] Fair(er) DRM scheduler Tvrtko Ursulin
` (22 preceding siblings ...)
2026-03-06 16:34 ` [PATCH v7 23/29] drm/nouveau: " Tvrtko Ursulin
@ 2026-03-06 16:34 ` Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 25/29] drm/panthor: " Tvrtko Ursulin
` (5 subsequent siblings)
29 siblings, 0 replies; 32+ messages in thread
From: Tvrtko Ursulin @ 2026-03-06 16:34 UTC (permalink / raw)
To: amd-gfx, dri-devel
Cc: kernel-dev, intel-xe, Danilo Krummrich, Philipp Stanner,
Tvrtko Ursulin, Boris Brezillon, Rob Herring, Steven Price
Remove member no longer used by the scheduler core.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Cc: Boris Brezillon <boris.brezillon@collabora.com>
Cc: Rob Herring <robh@kernel.org>
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Steven Price <steven.price@arm.com>
---
drivers/gpu/drm/panfrost/panfrost_job.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c
index d59b4863b8ad..2d12b83e900a 100644
--- a/drivers/gpu/drm/panfrost/panfrost_job.c
+++ b/drivers/gpu/drm/panfrost/panfrost_job.c
@@ -850,7 +850,6 @@ int panfrost_jm_init(struct panfrost_device *pfdev)
{
struct drm_sched_init_args args = {
.ops = &panfrost_sched_ops,
- .num_rqs = DRM_SCHED_PRIORITY_COUNT,
.credit_limit = 2,
.timeout = msecs_to_jiffies(JOB_TIMEOUT_MS),
.dev = pfdev->base.dev,
--
2.52.0
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH v7 25/29] drm/panthor: Remove drm_sched_init_args->num_rqs usage
2026-03-06 16:34 [PATCH v7 00/29] Fair(er) DRM scheduler Tvrtko Ursulin
` (23 preceding siblings ...)
2026-03-06 16:34 ` [PATCH v7 24/29] drm/panfrost: " Tvrtko Ursulin
@ 2026-03-06 16:34 ` Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 26/29] drm/sched: " Tvrtko Ursulin
` (4 subsequent siblings)
29 siblings, 0 replies; 32+ messages in thread
From: Tvrtko Ursulin @ 2026-03-06 16:34 UTC (permalink / raw)
To: amd-gfx, dri-devel
Cc: kernel-dev, intel-xe, Danilo Krummrich, Philipp Stanner,
Tvrtko Ursulin, Boris Brezillon, Steven Price, Liviu Dudau
Remove member no longer used by the scheduler core.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Cc: Boris Brezillon <boris.brezillon@collabora.com>
Cc: Steven Price <steven.price@arm.com>
Cc: Liviu Dudau <liviu.dudau@arm.com>
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Steven Price <steven.price@arm.com>
Reviewed-by: Liviu Dudau <liviu.dudau@arm.com>
---
drivers/gpu/drm/panthor/panthor_mmu.c | 1 -
drivers/gpu/drm/panthor/panthor_sched.c | 1 -
2 files changed, 2 deletions(-)
diff --git a/drivers/gpu/drm/panthor/panthor_mmu.c b/drivers/gpu/drm/panthor/panthor_mmu.c
index f8c41e36afa4..63eab0927303 100644
--- a/drivers/gpu/drm/panthor/panthor_mmu.c
+++ b/drivers/gpu/drm/panthor/panthor_mmu.c
@@ -2413,7 +2413,6 @@ panthor_vm_create(struct panthor_device *ptdev, bool for_mcu,
const struct drm_sched_init_args sched_args = {
.ops = &panthor_vm_bind_ops,
.submit_wq = ptdev->mmu->vm.wq,
- .num_rqs = 1,
.credit_limit = 1,
/* Bind operations are synchronous for now, no timeout needed. */
.timeout = MAX_SCHEDULE_TIMEOUT,
diff --git a/drivers/gpu/drm/panthor/panthor_sched.c b/drivers/gpu/drm/panthor/panthor_sched.c
index a70f1db0764e..675aa98caa7c 100644
--- a/drivers/gpu/drm/panthor/panthor_sched.c
+++ b/drivers/gpu/drm/panthor/panthor_sched.c
@@ -3487,7 +3487,6 @@ group_create_queue(struct panthor_group *group,
struct drm_sched_init_args sched_args = {
.ops = &panthor_queue_sched_ops,
.submit_wq = group->ptdev->scheduler->wq,
- .num_rqs = 1,
/*
* The credit limit argument tells us the total number of
* instructions across all CS slots in the ringbuffer, with
--
2.52.0
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH v7 26/29] drm/sched: Remove drm_sched_init_args->num_rqs usage
2026-03-06 16:34 [PATCH v7 00/29] Fair(er) DRM scheduler Tvrtko Ursulin
` (24 preceding siblings ...)
2026-03-06 16:34 ` [PATCH v7 25/29] drm/panthor: " Tvrtko Ursulin
@ 2026-03-06 16:34 ` Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 27/29] drm/v3d: " Tvrtko Ursulin
` (3 subsequent siblings)
29 siblings, 0 replies; 32+ messages in thread
From: Tvrtko Ursulin @ 2026-03-06 16:34 UTC (permalink / raw)
To: amd-gfx, dri-devel
Cc: kernel-dev, intel-xe, Danilo Krummrich, Philipp Stanner,
Tvrtko Ursulin, Matthew Brost, Christian König
Remove member no longer used by the scheduler core.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Philipp Stanner <phasta@kernel.org>
Cc: "Christian König" <ckoenig.leichtzumerken@gmail.com>
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
---
drivers/gpu/drm/scheduler/tests/mock_scheduler.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/drivers/gpu/drm/scheduler/tests/mock_scheduler.c b/drivers/gpu/drm/scheduler/tests/mock_scheduler.c
index 8e9ae7d980eb..14403a762335 100644
--- a/drivers/gpu/drm/scheduler/tests/mock_scheduler.c
+++ b/drivers/gpu/drm/scheduler/tests/mock_scheduler.c
@@ -290,7 +290,6 @@ struct drm_mock_scheduler *drm_mock_sched_new(struct kunit *test, long timeout)
{
struct drm_sched_init_args args = {
.ops = &drm_mock_scheduler_ops,
- .num_rqs = DRM_SCHED_PRIORITY_COUNT,
.credit_limit = U32_MAX,
.hang_limit = 1,
.timeout = timeout,
--
2.52.0
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH v7 27/29] drm/v3d: Remove drm_sched_init_args->num_rqs usage
2026-03-06 16:34 [PATCH v7 00/29] Fair(er) DRM scheduler Tvrtko Ursulin
` (25 preceding siblings ...)
2026-03-06 16:34 ` [PATCH v7 26/29] drm/sched: " Tvrtko Ursulin
@ 2026-03-06 16:34 ` Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 28/29] drm/xe: " Tvrtko Ursulin
` (2 subsequent siblings)
29 siblings, 0 replies; 32+ messages in thread
From: Tvrtko Ursulin @ 2026-03-06 16:34 UTC (permalink / raw)
To: amd-gfx, dri-devel
Cc: kernel-dev, intel-xe, Danilo Krummrich, Philipp Stanner,
Tvrtko Ursulin, Melissa Wen, Maíra Canal
Remove member no longer used by the scheduler core.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Cc: Melissa Wen <mwen@igalia.com>
Cc: "Maíra Canal" <mcanal@igalia.com>
Cc: dri-devel@lists.freedesktop.org
Acked-by: Melissa Wen <mwen@igalia.com>
---
drivers/gpu/drm/v3d/v3d_sched.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/drivers/gpu/drm/v3d/v3d_sched.c b/drivers/gpu/drm/v3d/v3d_sched.c
index 6dc871fc9a62..10f49b7ef648 100644
--- a/drivers/gpu/drm/v3d/v3d_sched.c
+++ b/drivers/gpu/drm/v3d/v3d_sched.c
@@ -869,7 +869,6 @@ v3d_queue_sched_init(struct v3d_dev *v3d, const struct drm_sched_backend_ops *op
enum v3d_queue queue, const char *name)
{
struct drm_sched_init_args args = {
- .num_rqs = DRM_SCHED_PRIORITY_COUNT,
.credit_limit = 1,
.timeout = msecs_to_jiffies(500),
.dev = v3d->drm.dev,
--
2.52.0
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH v7 28/29] drm/xe: Remove drm_sched_init_args->num_rqs usage
2026-03-06 16:34 [PATCH v7 00/29] Fair(er) DRM scheduler Tvrtko Ursulin
` (26 preceding siblings ...)
2026-03-06 16:34 ` [PATCH v7 27/29] drm/v3d: " Tvrtko Ursulin
@ 2026-03-06 16:34 ` Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 29/29] drm/sched: Remove drm_sched_init_args->num_rqs Tvrtko Ursulin
2026-03-08 22:37 ` Claude review: Fair(er) DRM scheduler Claude Code Review Bot
29 siblings, 0 replies; 32+ messages in thread
From: Tvrtko Ursulin @ 2026-03-06 16:34 UTC (permalink / raw)
To: amd-gfx, dri-devel
Cc: kernel-dev, intel-xe, Danilo Krummrich, Philipp Stanner,
Tvrtko Ursulin, Lucas De Marchi, Thomas Hellström,
Rodrigo Vivi, Matthew Brost
Remove member no longer used by the scheduler core.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: "Thomas Hellström" <thomas.hellstrom@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: intel-xe@lists.freedesktop.org
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
---
drivers/gpu/drm/xe/xe_dep_scheduler.c | 1 -
drivers/gpu/drm/xe/xe_execlist.c | 1 -
drivers/gpu/drm/xe/xe_gpu_scheduler.c | 1 -
3 files changed, 3 deletions(-)
diff --git a/drivers/gpu/drm/xe/xe_dep_scheduler.c b/drivers/gpu/drm/xe/xe_dep_scheduler.c
index 51d99fee9aa5..004aac8b89e6 100644
--- a/drivers/gpu/drm/xe/xe_dep_scheduler.c
+++ b/drivers/gpu/drm/xe/xe_dep_scheduler.c
@@ -78,7 +78,6 @@ xe_dep_scheduler_create(struct xe_device *xe,
const struct drm_sched_init_args args = {
.ops = &sched_ops,
.submit_wq = submit_wq,
- .num_rqs = 1,
.credit_limit = job_limit,
.timeout = MAX_SCHEDULE_TIMEOUT,
.name = name,
diff --git a/drivers/gpu/drm/xe/xe_execlist.c b/drivers/gpu/drm/xe/xe_execlist.c
index 755a2bff5d7b..1f8d358e60fd 100644
--- a/drivers/gpu/drm/xe/xe_execlist.c
+++ b/drivers/gpu/drm/xe/xe_execlist.c
@@ -337,7 +337,6 @@ static int execlist_exec_queue_init(struct xe_exec_queue *q)
struct drm_gpu_scheduler *sched;
const struct drm_sched_init_args args = {
.ops = &drm_sched_ops,
- .num_rqs = 1,
.credit_limit = xe_lrc_ring_size() / MAX_JOB_SIZE_BYTES,
.hang_limit = XE_SCHED_HANG_LIMIT,
.timeout = XE_SCHED_JOB_TIMEOUT,
diff --git a/drivers/gpu/drm/xe/xe_gpu_scheduler.c b/drivers/gpu/drm/xe/xe_gpu_scheduler.c
index 9c8004d5dd91..67d8ce368486 100644
--- a/drivers/gpu/drm/xe/xe_gpu_scheduler.c
+++ b/drivers/gpu/drm/xe/xe_gpu_scheduler.c
@@ -66,7 +66,6 @@ int xe_sched_init(struct xe_gpu_scheduler *sched,
const struct drm_sched_init_args args = {
.ops = ops,
.submit_wq = submit_wq,
- .num_rqs = 1,
.credit_limit = hw_submission,
.hang_limit = hang_limit,
.timeout = timeout,
--
2.52.0
^ permalink raw reply related [flat|nested] 32+ messages in thread
* [PATCH v7 29/29] drm/sched: Remove drm_sched_init_args->num_rqs
2026-03-06 16:34 [PATCH v7 00/29] Fair(er) DRM scheduler Tvrtko Ursulin
` (27 preceding siblings ...)
2026-03-06 16:34 ` [PATCH v7 28/29] drm/xe: " Tvrtko Ursulin
@ 2026-03-06 16:34 ` Tvrtko Ursulin
2026-03-08 22:37 ` Claude review: Fair(er) DRM scheduler Claude Code Review Bot
29 siblings, 0 replies; 32+ messages in thread
From: Tvrtko Ursulin @ 2026-03-06 16:34 UTC (permalink / raw)
To: amd-gfx, dri-devel
Cc: kernel-dev, intel-xe, Danilo Krummrich, Philipp Stanner,
Tvrtko Ursulin, Christian König, Matthew Brost
Remove member no longer used by the scheduler core and the drivers.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Philipp Stanner <phasta@kernel.org>
Acked-by: Danilo Krummrich <dakr@kernel.org>
---
include/drm/gpu_scheduler.h | 3 ---
1 file changed, 3 deletions(-)
diff --git a/include/drm/gpu_scheduler.h b/include/drm/gpu_scheduler.h
index cea2ee956422..53417baebd49 100644
--- a/include/drm/gpu_scheduler.h
+++ b/include/drm/gpu_scheduler.h
@@ -608,8 +608,6 @@ struct drm_gpu_scheduler {
* @ops: backend operations provided by the driver
* @submit_wq: workqueue to use for submission. If NULL, an ordered wq is
* allocated and used.
- * @num_rqs: Number of run-queues. This may be at most DRM_SCHED_PRIORITY_COUNT,
- * as there's usually one run-queue per priority, but may be less.
* @credit_limit: the number of credits this scheduler can hold from all jobs
* @hang_limit: number of times to allow a job to hang before dropping it.
* This mechanism is DEPRECATED. Set it to 0.
@@ -623,7 +621,6 @@ struct drm_sched_init_args {
const struct drm_sched_backend_ops *ops;
struct workqueue_struct *submit_wq;
struct workqueue_struct *timeout_wq;
- u32 num_rqs;
u32 credit_limit;
unsigned int hang_limit;
long timeout;
--
2.52.0
^ permalink raw reply related [flat|nested] 32+ messages in thread
* Re: [PATCH v7 04/29] drm/sched: Add some scheduling quality unit tests
2026-03-06 16:34 ` [PATCH v7 04/29] drm/sched: Add some scheduling quality unit tests Tvrtko Ursulin
@ 2026-03-08 10:10 ` kernel test robot
0 siblings, 0 replies; 32+ messages in thread
From: kernel test robot @ 2026-03-08 10:10 UTC (permalink / raw)
To: Tvrtko Ursulin, amd-gfx, dri-devel
Cc: llvm, oe-kbuild-all, kernel-dev, intel-xe, Danilo Krummrich,
Philipp Stanner, Tvrtko Ursulin, Christian König,
Matthew Brost, Pierre-Eric Pelloux-Prayer
Hi Tvrtko,
kernel test robot noticed the following build errors:
[auto build test ERROR on drm-misc/drm-misc-next]
[also build test ERROR on drm-xe/drm-xe-next daeinki-drm-exynos/exynos-drm-next drm/drm-next drm-i915/for-linux-next drm-i915/for-linux-next-fixes drm-tip/drm-tip linus/master v7.0-rc2 next-20260306]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Tvrtko-Ursulin/drm-sched-Disallow-initializing-entities-with-no-schedulers/20260307-012142
base: https://gitlab.freedesktop.org/drm/misc/kernel.git drm-misc-next
patch link: https://lore.kernel.org/r/20260306163445.97243-5-tvrtko.ursulin%40igalia.com
patch subject: [PATCH v7 04/29] drm/sched: Add some scheduling quality unit tests
config: riscv-allyesconfig (https://download.01.org/0day-ci/archive/20260308/202603081744.gNhsEN20-lkp@intel.com/config)
compiler: clang version 16.0.6 (https://github.com/llvm/llvm-project 7cbf1a2591520c2491aa35339f227775f4d3adf6)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260308/202603081744.gNhsEN20-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202603081744.gNhsEN20-lkp@intel.com/
All errors (new ones prefixed by >>):
>> drivers/gpu/drm/scheduler/tests/tests_scheduler.c:676:10: error: initializer element is not a compile-time constant
drm_sched_scheduler_two_clients_attr),
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/kunit/test.h:224:13: note: expanded from macro 'KUNIT_CASE_PARAM_ATTR'
.attr = attributes, .module_name = KBUILD_MODNAME}
^~~~~~~~~~
1 error generated.
vim +676 drivers/gpu/drm/scheduler/tests/tests_scheduler.c
672
673 static struct kunit_case drm_sched_scheduler_two_clients_tests[] = {
674 KUNIT_CASE_PARAM_ATTR(drm_sched_scheduler_two_clients_test,
675 drm_sched_scheduler_two_clients_gen_params,
> 676 drm_sched_scheduler_two_clients_attr),
677 {}
678 };
679
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
^ permalink raw reply [flat|nested] 32+ messages in thread
* Claude review: Fair(er) DRM scheduler
2026-03-06 16:34 [PATCH v7 00/29] Fair(er) DRM scheduler Tvrtko Ursulin
` (28 preceding siblings ...)
2026-03-06 16:34 ` [PATCH v7 29/29] drm/sched: Remove drm_sched_init_args->num_rqs Tvrtko Ursulin
@ 2026-03-08 22:37 ` Claude Code Review Bot
29 siblings, 0 replies; 32+ messages in thread
From: Claude Code Review Bot @ 2026-03-08 22:37 UTC (permalink / raw)
To: dri-devel-reviews
Overall Series Review
Subject: Fair(er) DRM scheduler
Author: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Patches: 31
Reviewed: 2026-03-09T08:37:18.150766
---
This is a well-structured, v7 series by Tvrtko Ursulin that replaces the existing FIFO and round-robin scheduling policies in the DRM GPU scheduler with a new CFS-inspired "fair" scheduling algorithm based on virtual runtime. The series is mature, with acks from Danilo Krummrich and reviews from multiple maintainers across the affected subsystems.
**Strengths:**
- Clear progression: cleanups/consolidation first, then the new algorithm, then removal of old code and simplification
- Extensive unit tests added before the algorithm changes
- Well-documented commit messages explaining design trade-offs (particularly the GPU time accounting placement rationale in patch 8)
- The splitting point at patch 12 is well-chosen for staged merge strategy
- Comprehensive benchmarking data in the cover letter
- Clean removal of `num_rqs` across all drivers at the end
**Concerns:**
- The `container_of(entity->rq, typeof(*sched), rq)` pattern introduced in patch 14 is verbose and appears many times across amdgpu code. Worth noting but this is inherent to the embedding approach.
- The `drm_sched_entity_stats` lock granularity could be a future contention point under heavy workloads with many entities, though the current design is reasonable for now.
Overall, the series is in good shape and the approach is sound.
---
Generated by Claude Code Patch Reviewer
^ permalink raw reply [flat|nested] 32+ messages in thread
end of thread, other threads:[~2026-03-08 22:37 UTC | newest]
Thread overview: 32+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2026-03-06 16:34 [PATCH v7 00/29] Fair(er) DRM scheduler Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 01/29] drm/sched: Disallow initializing entities with no schedulers Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 02/29] drm/sched: Consolidate entity run queue management Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 03/29] drm/sched: Move run queue related code into a separate file Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 04/29] drm/sched: Add some scheduling quality unit tests Tvrtko Ursulin
2026-03-08 10:10 ` kernel test robot
2026-03-06 16:34 ` [PATCH v7 05/29] drm/sched: Add some more " Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 06/29] drm/sched: Implement RR via FIFO Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 07/29] drm/sched: Free all finished jobs at once Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 08/29] drm/sched: Account entity GPU time Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 09/29] drm/sched: Remove idle entity from tree Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 10/29] drm/sched: Add fair scheduling policy Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 11/29] drm/sched: Favour interactive clients slightly Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 12/29] drm/sched: Switch default policy to fair Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 13/29] drm/sched: Remove FIFO and RR and simplify to a single run queue Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 14/29] drm/sched: Embed run queue singleton into the scheduler Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 15/29] accel/amdxdna: Remove drm_sched_init_args->num_rqs usage Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 16/29] accel/rocket: " Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 17/29] accel/ethosu: " Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 18/29] drm/amdgpu: " Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 19/29] drm/etnaviv: " Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 20/29] drm/imagination: " Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 21/29] drm/lima: " Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 22/29] drm/msm: " Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 23/29] drm/nouveau: " Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 24/29] drm/panfrost: " Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 25/29] drm/panthor: " Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 26/29] drm/sched: " Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 27/29] drm/v3d: " Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 28/29] drm/xe: " Tvrtko Ursulin
2026-03-06 16:34 ` [PATCH v7 29/29] drm/sched: Remove drm_sched_init_args->num_rqs Tvrtko Ursulin
2026-03-08 22:37 ` Claude review: Fair(er) DRM scheduler Claude Code Review Bot
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