From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 091ACFF886D for ; Wed, 29 Apr 2026 09:38:58 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 4D1CA10EF04; Wed, 29 Apr 2026 09:38:57 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=collabora.com header.i=@collabora.com header.b="gb/niX4z"; dkim-atps=neutral Received: from bali.collaboradmins.com (bali.collaboradmins.com [148.251.105.195]) by gabe.freedesktop.org (Postfix) with ESMTPS id 0F2F610EEFE for ; Wed, 29 Apr 2026 09:38:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1777455534; bh=6j20uIsC0wojMfhp5u4Z4DBXV8WgEm3tMPG6FW8fDBc=; h=From:Subject:Date:To:Cc:From; b=gb/niX4zDrQV2jCeX/dPCVBAMSCyydFsJ7iQdKflaedI/800zkojYOIvlqHqOtUgw W5b9ny1M+/yI8U4ZAv+Z52jd9ldx5pFA/0LI30PuEHEboy3wGV1V7As6CuU9Akt65K Lke8nBs+HGyPz7Yng6nFWfIW4qIZfFvYjXq7NXYCiwamXfeviaTJ+ultkVthNg3PEK G+m3Wh0RUMzVesxqlC3fgXi2hW/+qdrbX/jqqhd7zCqNYhK8D9ADV4VVR3OQQjqM+s DmFznK2ilOFE2qHW+HpZtHh/swagjvHAiKlpqpsTeVG+CMxkxUYnIt+L3mDIXjALcL emJcwB0bQC9Fw== Received: from [100.64.0.11] (unknown [100.64.0.11]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: bbrezillon) by bali.collaboradmins.com (Postfix) with ESMTPSA id 5253617E0610; Wed, 29 Apr 2026 11:38:54 +0200 (CEST) From: Boris Brezillon Subject: [PATCH 00/10] drm/panthor: Reduce dma_fence signalling latency Date: Wed, 29 Apr 2026 11:38:27 +0200 Message-Id: <20260429-panthor-signal-from-irq-v1-0-4b92ae4142d2@collabora.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-B4-Tracking: v=1; b=H4sIAAAAAAAC/y2NQQ6CMBBFr0K6dkgpLQoxxnsYFyMUmWhbmKIxM d7dCi7fT/57bxEtk42iyd6C7ZMiBZ+g2GSiHdBfLVCXWCipKqlVDSP6eQgMka4e79BzcEA8QVe W1U73ulO1Euk9su3ptZhP55XZTo8UmNdROBsjLoEm2//928KYutS5LiojFRRwQ354umHeDiEck V3eBnf4BS4YLSRwNDfZVhuD0uxKrKU4fz5fRBIeI9gAAAA= X-Change-ID: 20260429-panthor-signal-from-irq-d33684f4d292 To: Steven Price , Liviu Dudau Cc: Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Boris Brezillon X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=ed25519-sha256; t=1777455534; l=3165; i=boris.brezillon@collabora.com; s=20260429; h=from:subject:message-id; bh=6j20uIsC0wojMfhp5u4Z4DBXV8WgEm3tMPG6FW8fDBc=; b=R5+nLDQqHQmpG18cq0lNzcKfyz+0a2I66THInR4MiidT+el5oNSWmXu6mKYvDb/bVmj1jU7ut PRylwGMzYS6AMZexT2lizKgUIM1uL/xntkZAKZuPxutTH35F+4xBo+u X-Developer-Key: i=boris.brezillon@collabora.com; a=ed25519; pk=eN+ORdOgQY7d5U+0kA8h5bf67XdD8bhKbjD/TCHexSY= X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Right now, panthor is one of the rare drivers to signal fences from work items (not even from the threaded IRQ handler). We could move that to the threaded handler, but that would still leave the latency caused by the scheduling of the IRQ thread. Instead, this patchset moves all the job IRQ processing to the raw IRQ handler, which is fine because what the current code does is demux the interrupts and deferring actual handling to sub work items. The only bits we keep in the IRQ path is the dma_fence signalling, which should be acceptable, in term of CPU cycles spent in the IRQ context. Pretty much all the patches except the last two are just preparing the ground to get there. The second to last one does the thread -> IRQ transition, and the last one is some experimental interrupt coalescing support that I've added because I noticed moving job IRQ handling to the raw handler generates quite a lot of interrupts in some case, and having the system constantly interrupted like that can be detrimental. Signed-off-by: Boris Brezillon --- Boris Brezillon (10): drm/panthor: Make panthor_irq::state a non-atomic field drm/panthor: Move the register accessors before the IRQ helpers drm/panthor: Replace the panthor_irq macro machinery by inline helpers drm/panthor: Extend the IRQ logic to allow fast/raw IRQ handlers drm/panthor: Make panthor_fw_{update,toggle}_reqs() callable from IRQ context drm/panthor: Prepare the scheduler logic for FW events in IRQ context drm/panthor: Automate CSG IRQ processing at group unbind time drm/panthor: Automatically enable interrupts in panthor_fw_wait_acks() drm/panthor: Process FW events in IRQ context drm/panthor: Introduce interrupt coalescing support for job IRQs drivers/gpu/drm/panthor/panthor_device.h | 358 ++++++++++++++--------- drivers/gpu/drm/panthor/panthor_drv.c | 1 + drivers/gpu/drm/panthor/panthor_fw.c | 226 +++++++++++++-- drivers/gpu/drm/panthor/panthor_fw.h | 11 +- drivers/gpu/drm/panthor/panthor_gpu.c | 27 +- drivers/gpu/drm/panthor/panthor_mmu.c | 38 +-- drivers/gpu/drm/panthor/panthor_pwr.c | 21 +- drivers/gpu/drm/panthor/panthor_sched.c | 475 ++++++++++++++----------------- 8 files changed, 698 insertions(+), 459 deletions(-) --- base-commit: 7455a0583a906533041a80e48c6a2e3230cce96e change-id: 20260429-panthor-signal-from-irq-d33684f4d292 prerequisite-message-id: <20260427155934.416502-1-karunika.choo@arm.com> prerequisite-patch-id: 70905a2eb09ab2b31d242a5ed5af3b42fb6a464c prerequisite-patch-id: aa4c22669f80328039762f25c0b3942bbadbdc89 prerequisite-patch-id: 7f61bcee3c4bb5703900b18d5b6e0f52e622f29d prerequisite-patch-id: 3402f4d60aa526d40113fc3d9b3e599f8f89e705 prerequisite-patch-id: 00ddbd3d455891f6950609614c1acd2baa78b0db prerequisite-patch-id: 6a9928f609e3757cadebb2df6795d0da55745f4e prerequisite-patch-id: fd91f68f25d4bc93eec405f0131f5ae4284bfaf2 prerequisite-patch-id: 553958a10a0ca2f20f7883ad4c752cfc7485c5a8 Best regards, -- Boris Brezillon