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 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,URIBL_BLOCKED,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 0C5D1C43381 for ; Tue, 29 Dec 2020 12:02:19 +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 CD3A020825 for ; Tue, 29 Dec 2020 12:02:18 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CD3A020825 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=chris-wilson.co.uk Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=intel-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id AEF2389321; Tue, 29 Dec 2020 12:02:03 +0000 (UTC) Received: from fireflyinternet.com (unknown [77.68.26.236]) by gabe.freedesktop.org (Postfix) with ESMTPS id 6F601892EF for ; Tue, 29 Dec 2020 12:02:01 +0000 (UTC) X-Default-Received-SPF: pass (skip=forwardok (res=PASS)) x-ip-name=78.156.65.138; Received: from build.alporthouse.com (unverified [78.156.65.138]) by fireflyinternet.com (Firefly Internet (M1)) with ESMTP id 23455200-1500050 for multiple; Tue, 29 Dec 2020 12:01:53 +0000 From: Chris Wilson To: intel-gfx@lists.freedesktop.org Date: Tue, 29 Dec 2020 12:01:29 +0000 Message-Id: <20201229120145.26045-40-chris@chris-wilson.co.uk> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20201229120145.26045-1-chris@chris-wilson.co.uk> References: <20201229120145.26045-1-chris@chris-wilson.co.uk> MIME-Version: 1.0 Subject: [Intel-gfx] [PATCH 40/56] drm/i915: Move saturated workload detection back to the context X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Chris Wilson Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" When we introduced the saturated workload detection to tell us to back off from semaphore usage [semaphores have a noticeable impact on contended bus cycles with the CPU for some heavy workloads], we first introduced it as a per-context tracker. This allows individual contexts to try and optimise their own usage, but we found that with the local tracking and the no-semaphore boosting, the first context to disable semaphores got a massive priority boost and so would starve the rest and all new contexts (as they started with semaphores enabled and lower priority). Hence we moved the saturated workload detection to the engine, and a consequence had to disable semaphores on virtual engines. Now that we do not have semaphore priority boosting, and try to fairly schedule irrespective of semaphore usage, we can move the tracking back to the context and virtual engines can now utilise the faster inter-engine synchronisation. If we see that any context fairs to use the semaphore, because the system is oversubscribed and was busy doing something else instead of spinning on the semaphore, we disable further usage of semaphores with that context until it idles again. This should restrict the semaphores to lightly utilised system where the latency between requests is more noticeable, and curtail the bus-contention from checking for signaled semaphores. References: 44d89409a12e ("drm/i915: Make the semaphore saturation mask global") Signed-off-by: Chris Wilson --- drivers/gpu/drm/i915/gt/intel_context.c | 3 +++ drivers/gpu/drm/i915/gt/intel_context_types.h | 2 ++ drivers/gpu/drm/i915/gt/intel_engine_pm.c | 2 -- drivers/gpu/drm/i915/gt/intel_engine_types.h | 2 -- .../gpu/drm/i915/gt/intel_execlists_submission.c | 15 --------------- drivers/gpu/drm/i915/i915_request.c | 4 ++-- 6 files changed, 7 insertions(+), 21 deletions(-) diff --git a/drivers/gpu/drm/i915/gt/intel_context.c b/drivers/gpu/drm/i915/gt/intel_context.c index 349e7fa1488d..b3eb7513659b 100644 --- a/drivers/gpu/drm/i915/gt/intel_context.c +++ b/drivers/gpu/drm/i915/gt/intel_context.c @@ -345,6 +345,9 @@ static int __intel_context_active(struct i915_active *active) { struct intel_context *ce = container_of(active, typeof(*ce), active); + CE_TRACE(ce, "active\n"); + ce->saturated = 0; + intel_context_get(ce); /* everything should already be activated by intel_context_pre_pin() */ diff --git a/drivers/gpu/drm/i915/gt/intel_context_types.h b/drivers/gpu/drm/i915/gt/intel_context_types.h index 679b268f0911..f3e04ae53c51 100644 --- a/drivers/gpu/drm/i915/gt/intel_context_types.h +++ b/drivers/gpu/drm/i915/gt/intel_context_types.h @@ -103,6 +103,8 @@ struct intel_context { } lrc; u32 tag; /* cookie passed to HW to track this context on submission */ + intel_engine_mask_t saturated; /* submitting semaphores too late? */ + /* Time on GPU as tracked by the hw. */ struct { struct ewma_runtime avg; diff --git a/drivers/gpu/drm/i915/gt/intel_engine_pm.c b/drivers/gpu/drm/i915/gt/intel_engine_pm.c index 511a379c794d..64b9b857c71c 100644 --- a/drivers/gpu/drm/i915/gt/intel_engine_pm.c +++ b/drivers/gpu/drm/i915/gt/intel_engine_pm.c @@ -254,8 +254,6 @@ static int __engine_park(struct intel_wakeref *wf) struct intel_engine_cs *engine = container_of(wf, typeof(*engine), wakeref); - engine->saturated = 0; - /* * If one and only one request is completed between pm events, * we know that we are inside the kernel context and it is diff --git a/drivers/gpu/drm/i915/gt/intel_engine_types.h b/drivers/gpu/drm/i915/gt/intel_engine_types.h index 824a187b2803..74e55e0fbc65 100644 --- a/drivers/gpu/drm/i915/gt/intel_engine_types.h +++ b/drivers/gpu/drm/i915/gt/intel_engine_types.h @@ -304,8 +304,6 @@ struct intel_engine_cs { struct intel_context *kernel_context; /* pinned */ - intel_engine_mask_t saturated; /* submitting semaphores too late? */ - struct { struct delayed_work work; struct i915_request *systole; diff --git a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c index 6d5a5e881335..8527bb8abadd 100644 --- a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c +++ b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c @@ -3333,21 +3333,6 @@ intel_execlists_create_virtual(struct intel_engine_cs **siblings, ve->base.instance = I915_ENGINE_CLASS_INVALID_VIRTUAL; ve->base.uabi_instance = I915_ENGINE_CLASS_INVALID_VIRTUAL; - /* - * The decision on whether to submit a request using semaphores - * depends on the saturated state of the engine. We only compute - * this during HW submission of the request, and we need for this - * state to be globally applied to all requests being submitted - * to this engine. Virtual engines encompass more than one physical - * engine and so we cannot accurately tell in advance if one of those - * engines is already saturated and so cannot afford to use a semaphore - * and be pessimized in priority for doing so -- if we are the only - * context using semaphores after all other clients have stopped, we - * will be starved on the saturated system. Such a global switch for - * semaphores is less than ideal, but alas is the current compromise. - */ - ve->base.saturated = ALL_ENGINES; - snprintf(ve->base.name, sizeof(ve->base.name), "virtual"); i915_sched_init_engine(&ve->base.active, ENGINE_VIRTUAL); diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c index 3f9bcc427d07..d73f4085f227 100644 --- a/drivers/gpu/drm/i915/i915_request.c +++ b/drivers/gpu/drm/i915/i915_request.c @@ -569,7 +569,7 @@ bool __i915_request_submit(struct i915_request *request) */ if (request->sched.semaphores && i915_sw_fence_signaled(&request->semaphore)) - engine->saturated |= request->sched.semaphores; + request->context->saturated |= request->sched.semaphores; engine->emit_fini_breadcrumb(request, request->ring->vaddr + request->postfix); @@ -1030,7 +1030,7 @@ already_busywaiting(struct i915_request *rq) * * See the are-we-too-late? check in __i915_request_submit(). */ - return rq->sched.semaphores | READ_ONCE(rq->engine->saturated); + return rq->sched.semaphores | READ_ONCE(rq->context->saturated); } static int -- 2.20.1 _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx