From patchwork Mon Jun 10 07:21:03 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chris Wilson X-Patchwork-Id: 10984185 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id AB0251932 for ; Mon, 10 Jun 2019 07:21:57 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 94F912883B for ; Mon, 10 Jun 2019 07:21:57 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 8583A28843; Mon, 10 Jun 2019 07:21:57 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id F17852883B for ; Mon, 10 Jun 2019 07:21:55 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 5592389122; Mon, 10 Jun 2019 07:21:55 +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 0064C89130 for ; Mon, 10 Jun 2019 07:21:50 +0000 (UTC) X-Default-Received-SPF: pass (skip=forwardok (res=PASS)) x-ip-name=78.156.65.138; Received: from haswell.alporthouse.com (unverified [78.156.65.138]) by fireflyinternet.com (Firefly Internet (M1)) with ESMTP id 16848358-1500050 for multiple; Mon, 10 Jun 2019 08:21:28 +0100 From: Chris Wilson To: intel-gfx@lists.freedesktop.org Date: Mon, 10 Jun 2019 08:21:03 +0100 Message-Id: <20190610072126.6355-6-chris@chris-wilson.co.uk> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190610072126.6355-1-chris@chris-wilson.co.uk> References: <20190610072126.6355-1-chris@chris-wilson.co.uk> MIME-Version: 1.0 Subject: [Intel-gfx] [PATCH 05/28] drm/i915: Make the semaphore saturation mask global X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Dmitry Ermilov Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" X-Virus-Scanned: ClamAV using ClamSMTP The idea behind keeping the saturation mask local to a context backfired spectacularly. The premise with the local mask was that we would be more proactive in attempting to use semaphores after each time the context idled, and that all new contexts would attempt to use semaphores ignoring the current state of the system. This turns out to be horribly optimistic. If the system state is still oversaturated and the existing workloads have all stopped using semaphores, the new workloads would attempt to use semaphores and be deprioritised behind real work. The new contexts would not switch off using semaphores until their initial batch of low priority work had completed. Given sufficient backload load of equal user priority, this would completely starve the new work of any GPU time. To compensate, remove the local tracking in favour of keeping it as global state on the engine -- once the system is saturated and semaphores are disabled, everyone stops attempting to use semaphores until the system is idle again. One of the reason for preferring local context tracking was that it worked with virtual engines, so for switching to global state we could either do a complete check of all the virtual siblings or simply disable semaphores for those requests. This takes the simpler approach of disabling semaphores on virtual engines. The downside is that the decision that the engine is saturated is a local measure -- we are only checking whether or not this context was scheduled in a timely fashion, it may be legitimately delayed due to user priorities. We still have the same dilemma though, that we do not want to employ the semaphore poll unless it will be used. Fixes: ca6e56f654e7 ("drm/i915: Disable semaphore busywaits on saturated systems") Signed-off-by: Chris Wilson Cc: Tvrtko Ursulin Cc: Dmitry Rogozhkin Cc: Dmitry Ermilov --- drivers/gpu/drm/i915/gt/intel_context.c | 2 -- 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 | 2 +- drivers/gpu/drm/i915/i915_request.c | 4 ++-- 6 files changed, 7 insertions(+), 7 deletions(-) diff --git a/drivers/gpu/drm/i915/gt/intel_context.c b/drivers/gpu/drm/i915/gt/intel_context.c index c78ec0b58e77..7e2b18ddda19 100644 --- a/drivers/gpu/drm/i915/gt/intel_context.c +++ b/drivers/gpu/drm/i915/gt/intel_context.c @@ -118,7 +118,6 @@ intel_context_init(struct intel_context *ce, ce->engine = engine; ce->ops = engine->cops; ce->sseu = engine->sseu; - ce->saturated = 0; INIT_LIST_HEAD(&ce->signal_link); INIT_LIST_HEAD(&ce->signals); @@ -161,7 +160,6 @@ void intel_context_enter_engine(struct intel_context *ce) void intel_context_exit_engine(struct intel_context *ce) { - ce->saturated = 0; intel_engine_pm_put(ce->engine); } diff --git a/drivers/gpu/drm/i915/gt/intel_context_types.h b/drivers/gpu/drm/i915/gt/intel_context_types.h index 825fcf0ac9c4..e47d5b7af5d4 100644 --- a/drivers/gpu/drm/i915/gt/intel_context_types.h +++ b/drivers/gpu/drm/i915/gt/intel_context_types.h @@ -53,8 +53,6 @@ struct intel_context { atomic_t pin_count; struct mutex pin_mutex; /* guards pinning and associated on-gpuing */ - intel_engine_mask_t saturated; /* submitting semaphores too late? */ - /** * active_tracker: Active tracker for the external rq activity * on this intel_context object. diff --git a/drivers/gpu/drm/i915/gt/intel_engine_pm.c b/drivers/gpu/drm/i915/gt/intel_engine_pm.c index ccf034764741..7bffa0c6f5a2 100644 --- a/drivers/gpu/drm/i915/gt/intel_engine_pm.c +++ b/drivers/gpu/drm/i915/gt/intel_engine_pm.c @@ -98,6 +98,8 @@ 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 01223864237a..d2dff9056ea0 100644 --- a/drivers/gpu/drm/i915/gt/intel_engine_types.h +++ b/drivers/gpu/drm/i915/gt/intel_engine_types.h @@ -292,6 +292,8 @@ struct intel_engine_cs { struct intel_context *kernel_context; /* pinned */ struct intel_context *preempt_context; /* pinned; optional */ + intel_engine_mask_t saturated; /* submitting semaphores too late? */ + unsigned long serial; unsigned long wakeref_serial; diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c index 497ac036c4a9..62220cf9d281 100644 --- a/drivers/gpu/drm/i915/gt/intel_lrc.c +++ b/drivers/gpu/drm/i915/gt/intel_lrc.c @@ -3144,7 +3144,6 @@ static void virtual_context_exit(struct intel_context *ce) struct virtual_engine *ve = container_of(ce, typeof(*ve), context); unsigned int n; - ce->saturated = 0; for (n = 0; n < ve->num_siblings; n++) intel_engine_pm_put(ve->siblings[n]); } @@ -3339,6 +3338,7 @@ intel_execlists_create_virtual(struct i915_gem_context *ctx, ve->base.uabi_class = I915_ENGINE_CLASS_INVALID; ve->base.instance = I915_ENGINE_CLASS_INVALID_VIRTUAL; ve->base.flags = I915_ENGINE_IS_VIRTUAL; + ve->base.saturated = ALL_ENGINES; snprintf(ve->base.name, sizeof(ve->base.name), "virtual"); diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c index da1e6984a8cc..8100ccf04c0b 100644 --- a/drivers/gpu/drm/i915/i915_request.c +++ b/drivers/gpu/drm/i915/i915_request.c @@ -459,7 +459,7 @@ void __i915_request_submit(struct i915_request *request) */ if (request->sched.semaphores && i915_sw_fence_signaled(&request->semaphore)) - request->hw_context->saturated |= request->sched.semaphores; + engine->saturated |= request->sched.semaphores; /* We may be recursing from the signal callback of another i915 fence */ spin_lock_nested(&request->lock, SINGLE_DEPTH_NESTING); @@ -839,7 +839,7 @@ already_busywaiting(struct i915_request *rq) * * See the are-we-too-late? check in __i915_request_submit(). */ - return rq->sched.semaphores | rq->hw_context->saturated; + return rq->sched.semaphores | rq->engine->saturated; } static int