From patchwork Tue May 18 23:58:29 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Matthew Brost X-Patchwork-Id: 12265775 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4D22DC433B4 for ; Tue, 18 May 2021 23:40:56 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 14D0160FF0 for ; Tue, 18 May 2021 23:40:56 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 14D0160FF0 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id C81426E0ED; Tue, 18 May 2021 23:40:44 +0000 (UTC) Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) by gabe.freedesktop.org (Postfix) with ESMTPS id A3C696E0EA; Tue, 18 May 2021 23:40:42 +0000 (UTC) IronPort-SDR: gd66hm7/gyIznChLmR/VxMqGslqEoHlnj5OWd+eKZ4FiWDi0/HZG/kGB5CGPb/acKHeQyZgKLt Woki8HhSup1w== X-IronPort-AV: E=McAfee;i="6200,9189,9988"; a="286378180" X-IronPort-AV: E=Sophos;i="5.82,310,1613462400"; d="scan'208";a="286378180" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 May 2021 16:40:40 -0700 IronPort-SDR: GM4emKcj8Xe3Gy7LgykDxxP7L1YHuXBSe9G2S9eHXsqNM/ONbnoOwdZliaX2jkzPAfOHSCn89I JWRI4gVHJjgA== X-IronPort-AV: E=Sophos;i="5.82,310,1613462400"; d="scan'208";a="439698312" Received: from dhiatt-server.jf.intel.com ([10.54.81.3]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 May 2021 16:40:39 -0700 From: Matthew Brost To: , Subject: [RFC 1/2] drm/doc/rfc: i915 GuC submission / DRM scheduler Date: Tue, 18 May 2021 16:58:29 -0700 Message-Id: <20210518235830.133834-2-matthew.brost@intel.com> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20210518235830.133834-1-matthew.brost@intel.com> References: <20210518235830.133834-1-matthew.brost@intel.com> 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: , Cc: matthew.brost@intel.com, tony.ye@intel.com, tvrtko.ursulin@intel.com, daniele.ceraolospurio@intel.com, jason.ekstrand@intel.com, michal.mrozek@intel.com, jon.bloomfield@intel.com, karl@freedesktop.org, mesa-dev@lists.freedesktop.org, daniel.vetter@intel.com, christian.koenig@amd.com, john.c.harrison@intel.com Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Add entry for i915 GuC submission / DRM scheduler integration plan. Follow up patch with details of new parallel submission uAPI to come. v2: (Daniel Vetter) - Expand explaination of why bonding isn't supported for GuC submission - CC some of the DRM scheduler maintainers - Add priority inheritance / boosting use case - Add reasoning for removing in order assumptions (Daniel Stone) - Add links to priority spec Cc: Christian König Cc: Luben Tuikov Cc: Alex Deucher Cc: Steven Price Cc: Jon Bloomfield Cc: Jason Ekstrand Cc: Dave Airlie Cc: Daniel Vetter Cc: Jason Ekstrand Cc: dri-devel@lists.freedesktop.org Signed-off-by: Matthew Brost --- Documentation/gpu/rfc/i915_scheduler.rst | 85 ++++++++++++++++++++++++ Documentation/gpu/rfc/index.rst | 4 ++ 2 files changed, 89 insertions(+) create mode 100644 Documentation/gpu/rfc/i915_scheduler.rst diff --git a/Documentation/gpu/rfc/i915_scheduler.rst b/Documentation/gpu/rfc/i915_scheduler.rst new file mode 100644 index 000000000000..7faa46cde088 --- /dev/null +++ b/Documentation/gpu/rfc/i915_scheduler.rst @@ -0,0 +1,85 @@ +========================================= +I915 GuC Submission/DRM Scheduler Section +========================================= + +Upstream plan +============= +For upstream the overall plan for landing GuC submission and integrating the +i915 with the DRM scheduler is: + +* Merge basic GuC submission + * Basic submission support for all gen11+ platforms + * Not enabled by default on any current platforms but can be enabled via + modparam enable_guc + * Lots of rework will need to be done to integrate with DRM scheduler so + no need to nit pick everything in the code, it just should be + functional, no major coding style / layering errors, and not regress + execlists + * Update IGTs / selftests as needed to work with GuC submission + * Enable CI on supported platforms for a baseline + * Rework / get CI heathly for GuC submission in place as needed +* Merge new parallel submission uAPI + * Bonding uAPI completely incompatible with GuC submission, plus it has + severe design issues in general, which is why we want to retire it no + matter what + * New uAPI adds I915_CONTEXT_ENGINES_EXT_PARALLEL context setup step + which configures a slot with N contexts + * After I915_CONTEXT_ENGINES_EXT_PARALLEL a user can submit N batches to + a slot in a single execbuf IOCTL and the batches run on the GPU in + paralllel + * Initially only for GuC submission but execlists can be supported if + needed +* Convert the i915 to use the DRM scheduler + * GuC submission backend fully integrated with DRM scheduler + * All request queues removed from backend (e.g. all backpressure + handled in DRM scheduler) + * Resets / cancels hook in DRM scheduler + * Watchdog hooks into DRM scheduler + * Lots of complexity of the GuC backend can be pulled out once + integrated with DRM scheduler (e.g. state machine gets + simplier, locking gets simplier, etc...) + * Execlist backend will do the minimum required to hook in the DRM + scheduler so it can live next to the fully integrated GuC backend + * Legacy interface + * Features like timeslicing / preemption / virtual engines would + be difficult to integrate with the DRM scheduler and these + features are not required for GuC submission as the GuC does + these things for us + * ROI low on fully integrating into DRM scheduler + * Fully integrating would add lots of complexity to DRM + scheduler + * Port i915 priority inheritance / boosting feature in DRM scheduler + * Used for i915 page flip, may be useful to other DRM drivers as + well + * Will be an optional feature in the DRM scheduler + * Remove in-order completion assumptions from DRM scheduler + * Even when using the DRM scheduler the backends will handle + preemption, timeslicing, etc... so it is possible for jobs to + finish out of order + * Pull out i915 priority levels and use DRM priority levels + * Optimize DRM scheduler as needed + +New uAPI for basic GuC submission +================================= +No major changes are required to the uAPI for basic GuC submission. The only +change is a new scheduler attribute: I915_SCHEDULER_CAP_STATIC_PRIORITY_MAP. +This attribute indicates the 2k i915 user priority levels are statically mapped +into 3 levels as follows: + +* -1k to -1 Low priority +* 0 Medium priority +* 1 to 1k High priority + +This is needed because the GuC only has 4 priority bands. The highest priority +band is reserved with the kernel. This aligns with the DRM scheduler priority +levels too. + +Spec references: +---------------- +https://www.khronos.org/registry/EGL/extensions/IMG/EGL_IMG_context_priority.txt +https://www.khronos.org/registry/vulkan/specs/1.2-extensions/html/chap5.html#devsandqueues-priority +https://spec.oneapi.com/level-zero/latest/core/api.html#ze-command-queue-priority-t + +New parallel submission uAPI +============================ +Details to come in a following patch. diff --git a/Documentation/gpu/rfc/index.rst b/Documentation/gpu/rfc/index.rst index 05670442ca1b..91e93a705230 100644 --- a/Documentation/gpu/rfc/index.rst +++ b/Documentation/gpu/rfc/index.rst @@ -19,3 +19,7 @@ host such documentation: .. toctree:: i915_gem_lmem.rst + +.. toctree:: + + i915_scheduler.rst