From patchwork Tue Nov 12 09:28:46 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chris Wilson X-Patchwork-Id: 11238923 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 353411747 for ; Tue, 12 Nov 2019 09:29:34 +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 1DCA621925 for ; Tue, 12 Nov 2019 09:29:34 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1DCA621925 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 5F6986EAB0; Tue, 12 Nov 2019 09:29:19 +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 DABA76E0FB for ; Tue, 12 Nov 2019 09:29:14 +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 19170025-1500050 for multiple; Tue, 12 Nov 2019 09:28:59 +0000 From: Chris Wilson To: intel-gfx@lists.freedesktop.org Date: Tue, 12 Nov 2019 09:28:46 +0000 Message-Id: <20191112092854.869-19-chris@chris-wilson.co.uk> X-Mailer: git-send-email 2.24.0 In-Reply-To: <20191112092854.869-1-chris@chris-wilson.co.uk> References: <20191112092854.869-1-chris@chris-wilson.co.uk> MIME-Version: 1.0 Subject: [Intel-gfx] [PATCH 19/27] drm/i915/gt: Expose preempt reset timeout via sysfs 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" After initialising a preemption request, we give the current resident a small amount of time to vacate the GPU. The preemption request is for a higher priority context and should be immediate to maintain high quality of service (and avoid priority inversion). However, the preemption granularity of the GPU can be quite coarse and so we need a compromise. The preempt timeout can be adjusted per-engine using, /sys/class/drm/card?/engine/*/preempt_timeout_ms and can be disabled by setting it to 0. Signed-off-by: Chris Wilson --- drivers/gpu/drm/i915/Kconfig.profile | 3 ++ drivers/gpu/drm/i915/gt/intel_engine_sysfs.c | 48 ++++++++++++++++++++ drivers/gpu/drm/i915/gt/intel_lrc.c | 2 +- 3 files changed, 52 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/Kconfig.profile b/drivers/gpu/drm/i915/Kconfig.profile index d0fece34933b..233bcdb6a6ca 100644 --- a/drivers/gpu/drm/i915/Kconfig.profile +++ b/drivers/gpu/drm/i915/Kconfig.profile @@ -33,6 +33,9 @@ config DRM_I915_PREEMPT_TIMEOUT expires, the HW will be reset to allow the more important context to execute. + This is adjustable via + /sys/class/drm/card?/engine/*/preempt_timeout_ms + May be 0 to disable the timeout. config DRM_I915_MAX_REQUEST_BUSYWAIT diff --git a/drivers/gpu/drm/i915/gt/intel_engine_sysfs.c b/drivers/gpu/drm/i915/gt/intel_engine_sysfs.c index 2b65fed76435..d299c66cf7ec 100644 --- a/drivers/gpu/drm/i915/gt/intel_engine_sysfs.c +++ b/drivers/gpu/drm/i915/gt/intel_engine_sysfs.c @@ -271,6 +271,50 @@ stop_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) static struct kobj_attribute stop_timeout_attr = __ATTR(stop_timeout_ms, 0644, stop_show, stop_store); +static ssize_t +preempt_timeout_store(struct kobject *kobj, struct kobj_attribute *attr, + const char *buf, size_t count) +{ + struct intel_engine_cs *engine = kobj_to_engine(kobj); + unsigned long long timeout; + int err; + + /* + * After initialising a preemption request, we give the current + * resident a small amount of time to vacate the GPU. The preemption + * request is for a higher priority context and should be immediate to + * maintain high quality of service (and avoid priority inversion). + * However, the preemption granularity of the GPU can be quite coarse + * and so we need a compromise. + */ + + err = kstrtoull(buf, 0, &timeout); + if (err) + return err; + + if (timeout > jiffies_to_msecs(MAX_SCHEDULE_TIMEOUT)) + return -EINVAL; + + WRITE_ONCE(engine->props.preempt_timeout_ms, timeout); + + if (READ_ONCE(engine->execlists.pending[0])) + set_timer_ms(&engine->execlists.preempt, timeout); + + return count; +} + +static ssize_t +preempt_timeout_show(struct kobject *kobj, struct kobj_attribute *attr, + char *buf) +{ + struct intel_engine_cs *engine = kobj_to_engine(kobj); + + return sprintf(buf, "%lu\n", engine->props.preempt_timeout_ms); +} + +static struct kobj_attribute preempt_timeout_attr = +__ATTR(preempt_timeout_ms, 0644, preempt_timeout_show, preempt_timeout_store); + static void kobj_engine_release(struct kobject *kobj) { kfree(kobj); @@ -341,6 +385,10 @@ void intel_engines_add_sysfs(struct drm_i915_private *i915) sysfs_create_file(kobj, ×lice_duration_attr.attr)) goto err_engine; + if (intel_engine_has_preempt_reset(engine) && + sysfs_create_file(kobj, &preempt_timeout_attr.attr)) + goto err_engine; + if (0) { err_object: kobject_put(kobj); diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c index 1c334d381012..14e14c44562c 100644 --- a/drivers/gpu/drm/i915/gt/intel_lrc.c +++ b/drivers/gpu/drm/i915/gt/intel_lrc.c @@ -2224,7 +2224,7 @@ static noinline void preempt_reset(struct intel_engine_cs *engine) const unsigned int bit = I915_RESET_ENGINE + engine->id; unsigned long *lock = &engine->gt->reset.flags; - if (i915_modparams.reset < 3) + if (!intel_has_reset_engine(engine->gt)) return; if (test_and_set_bit(bit, lock))