From patchwork Wed Sep 19 19:55:19 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chris Wilson X-Patchwork-Id: 10606463 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 A0535112B for ; Wed, 19 Sep 2018 19:56:32 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 908B82CB2A for ; Wed, 19 Sep 2018 19:56:32 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 8522E2CB39; Wed, 19 Sep 2018 19:56:32 +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 21D512CB2A for ; Wed, 19 Sep 2018 19:56:32 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 7566D6E234; Wed, 19 Sep 2018 19:56:22 +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 0D0F36E1B8 for ; Wed, 19 Sep 2018 19:56:10 +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 13826641-1500050 for multiple; Wed, 19 Sep 2018 20:55:47 +0100 From: Chris Wilson To: intel-gfx@lists.freedesktop.org Date: Wed, 19 Sep 2018 20:55:19 +0100 Message-Id: <20180919195544.1511-15-chris@chris-wilson.co.uk> X-Mailer: git-send-email 2.19.0 In-Reply-To: <20180919195544.1511-1-chris@chris-wilson.co.uk> References: <20180919195544.1511-1-chris@chris-wilson.co.uk> MIME-Version: 1.0 Subject: [Intel-gfx] [PATCH 15/40] drm/i915: Priority boost for new clients 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: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" X-Virus-Scanned: ClamAV using ClamSMTP Taken from an idea used for FQ_CODEL, we give the first request of a new request flows a small priority boost. These flows are likely to correspond with short, interactive tasks and so be more latency sensitive than the longer free running queues. As soon as the client has more than one request in the queue, further requests are not boosted and it settles down into ordinary steady state behaviour. Such small kicks dramatically help combat the starvation issue, by allowing each client the opportunity to run even when the system is under heavy throughput load (within the constraints of the user selected priority). v2: Mark the preempted request as the start of a new flow, to prevent a single client being continually gazumped by its peers. Testcase: igt/benchmarks/rrul Signed-off-by: Chris Wilson Cc: Tvrtko Ursulin Cc: Joonas Lahtinen Reviewed-by: Tvrtko Ursulin --- drivers/gpu/drm/i915/i915_request.c | 16 ++++++++++++++-- drivers/gpu/drm/i915/i915_scheduler.h | 4 +++- drivers/gpu/drm/i915/intel_lrc.c | 25 +++++++++++++++++++------ 3 files changed, 36 insertions(+), 9 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c index a492385b2089..56140ca054e8 100644 --- a/drivers/gpu/drm/i915/i915_request.c +++ b/drivers/gpu/drm/i915/i915_request.c @@ -1127,8 +1127,20 @@ void i915_request_add(struct i915_request *request) */ local_bh_disable(); rcu_read_lock(); /* RCU serialisation for set-wedged protection */ - if (engine->schedule) - engine->schedule(request, &request->gem_context->sched); + if (engine->schedule) { + struct i915_sched_attr attr = request->gem_context->sched; + + /* + * Boost priorities to new clients (new request flows). + * + * Allow interactive/synchronous clients to jump ahead of + * the bulk clients. (FQ_CODEL) + */ + if (!prev || i915_request_completed(prev)) + attr.priority |= I915_PRIORITY_NEWCLIENT; + + engine->schedule(request, &attr); + } rcu_read_unlock(); i915_sw_fence_commit(&request->submit); local_bh_enable(); /* Kick the execlists tasklet if just scheduled */ diff --git a/drivers/gpu/drm/i915/i915_scheduler.h b/drivers/gpu/drm/i915/i915_scheduler.h index 7edfad0abfd7..93e43e263d8c 100644 --- a/drivers/gpu/drm/i915/i915_scheduler.h +++ b/drivers/gpu/drm/i915/i915_scheduler.h @@ -19,12 +19,14 @@ enum { I915_PRIORITY_INVALID = INT_MIN }; -#define I915_USER_PRIORITY_SHIFT 0 +#define I915_USER_PRIORITY_SHIFT 1 #define I915_USER_PRIORITY(x) ((x) << I915_USER_PRIORITY_SHIFT) #define I915_PRIORITY_COUNT BIT(I915_USER_PRIORITY_SHIFT) #define I915_PRIORITY_MASK (-I915_PRIORITY_COUNT) +#define I915_PRIORITY_NEWCLIENT ((u8)BIT(0)) + struct i915_sched_attr { /** * @priority: execution and service priority diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c index aeae82b5223c..ee9a656e549c 100644 --- a/drivers/gpu/drm/i915/intel_lrc.c +++ b/drivers/gpu/drm/i915/intel_lrc.c @@ -363,9 +363,9 @@ static void unwind_wa_tail(struct i915_request *rq) static void __unwind_incomplete_requests(struct intel_engine_cs *engine) { - struct i915_request *rq, *rn; + struct i915_request *rq, *rn, *active = NULL; struct list_head *uninitialized_var(pl); - int last_prio = I915_PRIORITY_INVALID; + int prio = I915_PRIORITY_INVALID | I915_PRIORITY_NEWCLIENT; lockdep_assert_held(&engine->timeline.lock); @@ -373,19 +373,32 @@ static void __unwind_incomplete_requests(struct intel_engine_cs *engine) &engine->timeline.requests, link) { if (i915_request_completed(rq)) - return; + break; __i915_request_unsubmit(rq); unwind_wa_tail(rq); GEM_BUG_ON(rq_prio(rq) == I915_PRIORITY_INVALID); - if (rq_prio(rq) != last_prio) { - last_prio = rq_prio(rq); - pl = lookup_priolist(engine, last_prio); + if (rq_prio(rq) != prio) { + prio = rq_prio(rq); + pl = lookup_priolist(engine, prio); } GEM_BUG_ON(RB_EMPTY_ROOT(&engine->execlists.queue.rb_root)); list_add(&rq->sched.link, pl); + + active = rq; + } + + /* + * The active request is now effectively the start of a new client + * stream, so give it the equivalent small priority bump to prevent + * it being gazumped a second time by another peer. + */ + if (!(prio & I915_PRIORITY_NEWCLIENT)) { + prio |= I915_PRIORITY_NEWCLIENT; + list_move_tail(&active->sched.link, + lookup_priolist(engine, prio)); } }