From patchwork Thu Feb 16 10:59:12 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tvrtko Ursulin X-Patchwork-Id: 13142940 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 06184C64EC4 for ; Thu, 16 Feb 2023 10:59:40 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 6999310E2BE; Thu, 16 Feb 2023 10:59:31 +0000 (UTC) Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) by gabe.freedesktop.org (Postfix) with ESMTPS id EEC0C10E2BE; Thu, 16 Feb 2023 10:59:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1676545169; x=1708081169; h=from:to:subject:date:message-id:mime-version: content-transfer-encoding; bh=4Pkn9PSYJ5E+ITtnoLCo59F8QKqtW+QZqBQ0zPJSloY=; b=g+6QLqUuisFoxZGn1fDIFG3SkQS0Q3zbHgpaHmDYoKiSnRuLS3r4bXXI /TSQ7RD1vOoA/ndHVnxFmjZXdBGI8evYQoOfgIK1jISLwSwlAOIwApaWj 5M2VLP5ThA5JKHPuzFbywNSFs4n6DPAcLxdC8X+WnrkYOkhjrZwV/upVA CrWDR9VmSXY7HRCBXw2+vB+E2900xV2NA418xV+N8hAECYb+1g0L8xrj8 j+JITdPb9ZXA3ezBR/SuEd6nk2OPPuylo5oLm4E/cjvVtQZroRlMwXcUG VD7BJzRpGOa/nk/q37jpwag5mqz2NL8x5bXhr21wwui4igPl5Et8x9/9a Q==; X-IronPort-AV: E=McAfee;i="6500,9779,10622"; a="311317593" X-IronPort-AV: E=Sophos;i="5.97,302,1669104000"; d="scan'208";a="311317593" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Feb 2023 02:59:28 -0800 X-IronPort-AV: E=McAfee;i="6500,9779,10622"; a="812917903" X-IronPort-AV: E=Sophos;i="5.97,302,1669104000"; d="scan'208";a="812917903" Received: from murrayal-mobl.ger.corp.intel.com (HELO localhost.localdomain) ([10.213.229.164]) by fmsmga001-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Feb 2023 02:59:27 -0800 From: Tvrtko Ursulin To: Intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org Subject: [RFC v3 0/9] Waitboost drm syncobj waits Date: Thu, 16 Feb 2023 10:59:12 +0000 Message-Id: <20230216105921.624960-1-tvrtko.ursulin@linux.intel.com> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 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" From: Tvrtko Ursulin In i915 we have this concept of "wait boosting" where we give a priority boost for instance to fences which are actively waited upon from userspace. This has it's pros and cons and can certainly be discussed at lenght. However fact is some workloads really like it. Problem is that with the arrival of drm syncobj and a new userspace waiting entry point it added, the waitboost mechanism was bypassed. AFAIU this mostly happens with all Vulkan based userspaces. Hence I cooked up this mini series to see if discussion about restoring the waitboost can be had. The series adds a concept of "wait count" to dma fence which is intended to represent explicit userspace waits. It is therefore incremented for every explicit dma_fence_enable_sw_signaling and dma_fence_add_wait_callback (like dma_fence_add_callback but from explicit/userspace wait paths). Individual drivers can then inspect this via dma_fence_wait_count() and decide to wait boost the waits on such fences. Patch has been slightly tested for performance impact by Google using some clvk workloads and shows a good improvement (frame time improved from 16ms to 13ms). It is also important to mention that benefits of waitboosting are not only about workloads related to frame presentation time, but also for serialized computations which constantly move between the CPU and GPU. *) https://gitlab.freedesktop.org/drm/intel/-/issues/8014 v2: * Small fixups based on CI feedback: * Handle decrement correctly for already signalled case while adding callback. * Remove i915 assert which was making sure struct i915_request does not grow. * Split out the i915 patch into three separate functional changes. v3: * Handle drivers which open-code callback additions. Tvrtko Ursulin (9): dma-fence: Move i915 helpers into common dma-fence: Add callback initialization helper drm/i915: Use fence callback initialization helper drm/vmwgfx: Use fence callback initialization helper dma-fence: Track explicit waiters drm/syncobj: Mark syncobj waits as external waiters drm/i915: Waitboost external waits drm/i915: Mark waits as explicit drm/i915: Wait boost requests waited upon by others drivers/dma-buf/dma-fence.c | 137 ++++++++++++++------ drivers/gpu/drm/drm_syncobj.c | 6 +- drivers/gpu/drm/i915/gt/intel_breadcrumbs.c | 22 ---- drivers/gpu/drm/i915/gt/intel_engine_pm.c | 1 - drivers/gpu/drm/i915/i915_active.c | 2 +- drivers/gpu/drm/i915/i915_active.h | 2 +- drivers/gpu/drm/i915/i915_request.c | 13 +- drivers/gpu/drm/vmwgfx/vmwgfx_fence.c | 2 +- include/linux/dma-fence.h | 26 ++++ 9 files changed, 141 insertions(+), 70 deletions(-)