From patchwork Wed Jan 13 12:51:55 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chris Wilson X-Patchwork-Id: 12016747 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7FCA5C433E0 for ; Wed, 13 Jan 2021 12:52:32 +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 9D5FB233F6 for ; Wed, 13 Jan 2021 12:52:31 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9D5FB233F6 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 1EE976E986; Wed, 13 Jan 2021 12:52:31 +0000 (UTC) Received: from fireflyinternet.com (unknown [77.68.26.236]) by gabe.freedesktop.org (Postfix) with ESMTPS id 738E96E986 for ; Wed, 13 Jan 2021 12:52:28 +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 23584309-1500050 for multiple; Wed, 13 Jan 2021 12:51:56 +0000 From: Chris Wilson To: intel-gfx@lists.freedesktop.org Date: Wed, 13 Jan 2021 12:51:55 +0000 Message-Id: <20210113125155.1029-1-chris@chris-wilson.co.uk> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Subject: [Intel-gfx] [PATCH] drm/i915/selftests: Bump the scheduling threshold for fast heartbeats 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" Since we are system_highpri_wq, we expected the heartbeat to be scheduled promptly. However, we see delays of over 10ms upsetting our assertions. Accept this as inevitable and bump the error threshold to 20ms (from 6ms). Signed-off-by: Chris Wilson --- drivers/gpu/drm/i915/gt/selftest_engine_heartbeat.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/i915/gt/selftest_engine_heartbeat.c b/drivers/gpu/drm/i915/gt/selftest_engine_heartbeat.c index b88aa35ad75b..807c445f7c70 100644 --- a/drivers/gpu/drm/i915/gt/selftest_engine_heartbeat.c +++ b/drivers/gpu/drm/i915/gt/selftest_engine_heartbeat.c @@ -197,6 +197,7 @@ static int cmp_u32(const void *_a, const void *_b) static int __live_heartbeat_fast(struct intel_engine_cs *engine) { + const int error_threshold = 20000; /* microseconds */ struct intel_context *ce; struct i915_request *rq; ktime_t t0, t1; @@ -254,12 +255,18 @@ static int __live_heartbeat_fast(struct intel_engine_cs *engine) times[0], times[ARRAY_SIZE(times) - 1]); - /* Min work delay is 2 * 2 (worst), +1 for scheduling, +1 for slack */ - if (times[ARRAY_SIZE(times) / 2] > jiffies_to_usecs(6)) { + /* + * Ideally, the upper bound on min work delay would be something like + * 2 * 2 (worst), +1 for scheduling, +1 for slack. In practice, we + * are, even with system_wq_highpri, at the mercy of the CPU scheduler + * and may be stuck behind some slow work for many millisecond. Such + * as our very own display workers. + */ + if (times[ARRAY_SIZE(times) / 2] > error_threshold) { pr_err("%s: Heartbeat delay was %uus, expected less than %dus\n", engine->name, times[ARRAY_SIZE(times) / 2], - jiffies_to_usecs(6)); + error_threshold); err = -EINVAL; }