From patchwork Mon May 11 07:57:15 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chris Wilson X-Patchwork-Id: 11539889 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 04A96912 for ; Mon, 11 May 2020 07:58:05 +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 E11FB20735 for ; Mon, 11 May 2020 07:58:04 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E11FB20735 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 2D8BA89CD9; Mon, 11 May 2020 07:58:03 +0000 (UTC) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from fireflyinternet.com (mail.fireflyinternet.com [109.228.58.192]) by gabe.freedesktop.org (Postfix) with ESMTPS id F1E8D6E267 for ; Mon, 11 May 2020 07:57:59 +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 21160797-1500050 for multiple; Mon, 11 May 2020 08:57:27 +0100 From: Chris Wilson To: intel-gfx@lists.freedesktop.org Date: Mon, 11 May 2020 08:57:15 +0100 Message-Id: <20200511075722.13483-13-chris@chris-wilson.co.uk> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200511075722.13483-1-chris@chris-wilson.co.uk> References: <20200511075722.13483-1-chris@chris-wilson.co.uk> MIME-Version: 1.0 Subject: [Intel-gfx] [PATCH 13/20] 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 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, we can move the tracking back to the context and virtual engines can now utilise the faster inter-engine synchronisation. References: 44d89409a12e ("drm/i915: Make the semaphore saturation mask global") Signed-off-by: Chris Wilson --- drivers/gpu/drm/i915/gt/intel_context.c | 1 + 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 -- drivers/gpu/drm/i915/gt/intel_lrc.c | 15 --------------- drivers/gpu/drm/i915/i915_request.c | 4 ++-- 6 files changed, 5 insertions(+), 21 deletions(-) diff --git a/drivers/gpu/drm/i915/gt/intel_context.c b/drivers/gpu/drm/i915/gt/intel_context.c index e4aece20bc80..762a251d553b 100644 --- a/drivers/gpu/drm/i915/gt/intel_context.c +++ b/drivers/gpu/drm/i915/gt/intel_context.c @@ -268,6 +268,7 @@ static int __intel_context_active(struct i915_active *active) if (err) goto err_timeline; + ce->saturated = 0; return 0; err_timeline: diff --git a/drivers/gpu/drm/i915/gt/intel_context_types.h b/drivers/gpu/drm/i915/gt/intel_context_types.h index 4954b0df4864..aed26d93c2ca 100644 --- a/drivers/gpu/drm/i915/gt/intel_context_types.h +++ b/drivers/gpu/drm/i915/gt/intel_context_types.h @@ -78,6 +78,8 @@ 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 d0a1078ef632..6d7fdba5adef 100644 --- a/drivers/gpu/drm/i915/gt/intel_engine_pm.c +++ b/drivers/gpu/drm/i915/gt/intel_engine_pm.c @@ -229,8 +229,6 @@ 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 c113b7805e65..2b1232a233bc 100644 --- a/drivers/gpu/drm/i915/gt/intel_engine_types.h +++ b/drivers/gpu/drm/i915/gt/intel_engine_types.h @@ -332,8 +332,6 @@ 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_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c index 382969c1c7ca..730f639a4477 100644 --- a/drivers/gpu/drm/i915/gt/intel_lrc.c +++ b/drivers/gpu/drm/i915/gt/intel_lrc.c @@ -5591,21 +5591,6 @@ 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"); intel_engine_init_active(&ve->base, ENGINE_VIRTUAL); diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c index 9738dab5a9f6..dae0b2c44951 100644 --- a/drivers/gpu/drm/i915/i915_request.c +++ b/drivers/gpu/drm/i915/i915_request.c @@ -469,7 +469,7 @@ 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); @@ -921,7 +921,7 @@ 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