From patchwork Wed May 9 12:04:18 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chris Wilson X-Patchwork-Id: 10389317 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 23C1F60153 for ; Wed, 9 May 2018 12:04:42 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 11B3428D1D for ; Wed, 9 May 2018 12:04:42 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 05DD328F26; Wed, 9 May 2018 12:04:42 +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 A302828D1D for ; Wed, 9 May 2018 12:04:41 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id DB5DE6ED2B; Wed, 9 May 2018 12:04:39 +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 1A8676ED24 for ; Wed, 9 May 2018 12:04:35 +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 11644594-1500050 for multiple; Wed, 09 May 2018 13:04:26 +0100 Received: by haswell.alporthouse.com (sSMTP sendmail emulation); Wed, 09 May 2018 13:04:27 +0100 From: Chris Wilson To: intel-gfx@lists.freedesktop.org Date: Wed, 9 May 2018 13:04:18 +0100 Message-Id: <20180509120419.6733-4-chris@chris-wilson.co.uk> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180509120419.6733-1-chris@chris-wilson.co.uk> References: <20180509120419.6733-1-chris@chris-wilson.co.uk> X-Originating-IP: 78.156.65.138 X-Country: code=GB country="United Kingdom" ip=78.156.65.138 Subject: [Intel-gfx] [PATCH v3 4/5] drm/i915/execlists: Direct submission from irq handler 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: , MIME-Version: 1.0 Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" X-Virus-Scanned: ClamAV using ClamSMTP Continuing the theme of bypassing ksoftirqd latency, also first try to directly submit from the CS interrupt handler to clear the ELSP and queue the next. In the past, we have been hesitant to do this as the context switch processing has been quite heavy, requiring forcewaked mmio. However, as we now can read the GPU state from the cacheable HWSP, it is relatively cheap! v2: Explain why we test_bit(IRQ_EXECLIST) after doing notify_ring (it's because the notify_ring() may itself trigger direct submission clearing the bit) Suggested-by: Tvrtko Ursulin Signed-off-by: Chris Wilson Cc: Tvrtko Ursulin --- drivers/gpu/drm/i915/i915_irq.c | 21 ++++++++++++++------- drivers/gpu/drm/i915/i915_tasklet.h | 19 +++++++++++++++++++ drivers/gpu/drm/i915/intel_guc_submission.c | 2 ++ 3 files changed, 35 insertions(+), 7 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c index f8aff5a5aa83..e1b3a7575fe7 100644 --- a/drivers/gpu/drm/i915/i915_irq.c +++ b/drivers/gpu/drm/i915/i915_irq.c @@ -1465,19 +1465,26 @@ gen8_cs_irq_handler(struct intel_engine_cs *engine, u32 iir) struct intel_engine_execlists * const execlists = &engine->execlists; bool tasklet = false; - if (iir & GT_CONTEXT_SWITCH_INTERRUPT) { - if (READ_ONCE(engine->execlists.active)) - tasklet = !test_and_set_bit(ENGINE_IRQ_EXECLIST, - &engine->irq_posted); - } + if (iir & GT_CONTEXT_SWITCH_INTERRUPT && READ_ONCE(execlists->active)) + tasklet = !test_and_set_bit(ENGINE_IRQ_EXECLIST, + &engine->irq_posted); if (iir & GT_RENDER_USER_INTERRUPT) { notify_ring(engine); - tasklet |= USES_GUC_SUBMISSION(engine->i915); + /* + * notify_ring() may trigger direct submission onto this + * engine, clearing the ENGINE_IRQ_EXECLIST bit. In that + * case, we don't want to resubmit and so clear the tasklet + * boolean. GuC never sets the ENGINE_IRQ_EXECLIST bit and + * so when using the GuC this equates to an unconditional + * setting of tasklet to true. + */ + if (!test_bit(ENGINE_IRQ_EXECLIST, &engine->irq_posted)) + tasklet = USES_GUC_SUBMISSION(engine->i915); } if (tasklet) - i915_tasklet_schedule(&execlists->tasklet); + i915_tasklet(&execlists->tasklet); } static void gen8_gt_irq_ack(struct drm_i915_private *i915, diff --git a/drivers/gpu/drm/i915/i915_tasklet.h b/drivers/gpu/drm/i915/i915_tasklet.h index bb8f03a03b29..6fcab4ec7f35 100644 --- a/drivers/gpu/drm/i915/i915_tasklet.h +++ b/drivers/gpu/drm/i915/i915_tasklet.h @@ -113,4 +113,23 @@ static inline void i915_tasklet_run(const struct i915_tasklet *t) __i915_tasklet_run(t); } +static inline bool i915_tasklet_try(struct i915_tasklet *t) +{ + if (unlikely(!tasklet_trylock(&t->base))) + return false; + + i915_tasklet_run(t); + tasklet_unlock(&t->base); + return true; +} + +static inline void i915_tasklet(struct i915_tasklet *t) +{ + if (!i915_tasklet_is_enabled(t)) /* GPU reset active */ + return; + + if (!i915_tasklet_try(t)) + i915_tasklet_schedule(t); +} + #endif /* _I915_TASKLET_H_ */ diff --git a/drivers/gpu/drm/i915/intel_guc_submission.c b/drivers/gpu/drm/i915/intel_guc_submission.c index f2ded1796523..4e09abf7e206 100644 --- a/drivers/gpu/drm/i915/intel_guc_submission.c +++ b/drivers/gpu/drm/i915/intel_guc_submission.c @@ -780,6 +780,8 @@ static void guc_submission_tasklet(unsigned long data) struct execlist_port *port = execlists->port; struct i915_request *rq; + clear_bit(ENGINE_IRQ_EXECLIST, &engine->irq_posted); + rq = port_request(port); while (rq && i915_request_completed(rq)) { trace_i915_request_out(rq);