From patchwork Thu Nov 9 16:41:17 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Patrick Bellasi X-Patchwork-Id: 118464 Delivered-To: patch@linaro.org Received: by 10.140.22.164 with SMTP id 33csp6816157qgn; Thu, 9 Nov 2017 08:41:57 -0800 (PST) X-Google-Smtp-Source: ABhQp+TRm9l8DHGxWLHvmlKL9v8rJcxek/JoO18NYwwJRwMJi73UZf92SAVY7eATgj2Us+LNLGAo X-Received: by 10.99.158.17 with SMTP id s17mr1024800pgd.218.1510245717022; Thu, 09 Nov 2017 08:41:57 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1510245717; cv=none; d=google.com; s=arc-20160816; b=Jg3bV8J43KwvzyYgtamKOXjxW43MIZfim5XOzvsvaWXE2zeEGu3JOgFkIiI2x39O3V EJJv/VKA0jaVZtffzb12mia7Fsj4hTbBwHLH/p0m+ahzBIU+ZPMTGmpEsVctJ3j5NIla tJ/VjTgsSDeKdSC+wMpffvEef4+J+SQIfvJVylwOKMJbTcuGY0gNBEY6Mn13YmeM50+V 8y3TF2Cfe7sQctlgvmIPAsE1aGuKnBk0UllGcMGdcCDJaUEZQIwDwMABNjA2j1lKmZYH Vnr7tvIa/P8nhKXYh9OVpy3a1UFZuYsMxkgXR/W5kKZQEwo4/5IvhmYP46d0qCddSW/O 7H5Q== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=29DKg49i1ma6XeEBwDbATjytt/YzfRmPvJnXjkYYqzU=; b=vljhe1oc7cBhO1K4WuI44Z5FLiG0uc6QzARqCtPCd9N1Sy6lMuqsqNkPW3Je0HDDmd KDJLARgJzxaasdnb6ov4vWKUaE8d6jGy7tUGTQfcv+mhr3PzK7qObFmQhz1wqA+quF+f Rogd2NvEmZD5p8kBCEk0yHSCQZsz8fRvVNER3Rdz25qCgbePYuxA/UcV3aQfZAfOS1PA lgP8EbXBjBwnCEznzbx4xHZIUne5G8VSgzalVPzMBDXdlHI3E1z9p7xqZ18TIRdIvqp2 HGlAEXKHzpz9HuKV/xi2PlsiCiiH6tP45/TQH2jSXtY21Vss5roS/AUqOZQN42KlmYru I2OQ== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id e9si6431324pgo.708.2017.11.09.08.41.55; Thu, 09 Nov 2017 08:41:57 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753605AbdKIQlx (ORCPT + 23 others); Thu, 9 Nov 2017 11:41:53 -0500 Received: from foss.arm.com ([217.140.101.70]:49260 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753007AbdKIQls (ORCPT ); Thu, 9 Nov 2017 11:41:48 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 114D51650; Thu, 9 Nov 2017 08:41:48 -0800 (PST) Received: from e110439-lin.cambridge.arm.com (e110439-lin.cambridge.arm.com [10.1.210.68]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id AC3D43F3DF; Thu, 9 Nov 2017 08:41:45 -0800 (PST) From: Patrick Bellasi To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Peter Zijlstra , "Rafael J . Wysocki" , Viresh Kumar , Vincent Guittot , Paul Turner , Dietmar Eggemann , Morten Rasmussen , Juri Lelli , Todd Kjos , Joel Fernandes , linux-pm@vger.kernel.org Subject: [PATCH 4/4] sched/cpufreq_schedutil: use util_est for OPP selection Date: Thu, 9 Nov 2017 16:41:17 +0000 Message-Id: <20171109164117.19401-5-patrick.bellasi@arm.com> X-Mailer: git-send-email 2.14.1 In-Reply-To: <20171109164117.19401-1-patrick.bellasi@arm.com> References: <20171109164117.19401-1-patrick.bellasi@arm.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When schedutil looks at the CPU utilization, the current PELT value for that CPU is returned straight away. In certain scenarios this can have undesired side effects and delays on frequency selection. For example, since the task utilization is decayed at wakeup time, a long sleeping big task newly enqueued it does not add immediately a significant contribution to the target CPU. This introduces some latency before schedutil will be able to detect the best frequency required by that task. Moreover, the PELT signal building up time is function of the current frequency, because of the scale invariant load tracking support. Thus, starting from a lower frequency, the utilization build-up time will increase even more and further delays the selection of the actual frequency which better serves the task requirements. In order to reduce these kind of latencies, this patch integrates the usage of the CPU's estimated utilization in the sugov_get_util function. The estimated utilization of a CPU is defined to be the maximum between its PELT's utilization and the sum of the estimated utilization of each currently RUNNABLE task on that CPU. This allows to properly represent the expected utilization of a CPU which, for example, it has just got a big task running after a long sleep period, and ultimately it allows to select the best frequency to run a task right after its wakes up. Signed-off-by: Patrick Bellasi Reviewed-by: Brendan Jackman Reviewed-by: Dietmar Eggemann Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Rafael J. Wysocki Cc: Viresh Kumar Cc: Paul Turner Cc: Vincent Guittot Cc: Morten Rasmussen Cc: Dietmar Eggemann Cc: linux-kernel@vger.kernel.org Cc: linux-pm@vger.kernel.org --- kernel/sched/cpufreq_schedutil.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) -- 2.14.1 diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c index 137733db6727..d72231e30d44 100644 --- a/kernel/sched/cpufreq_schedutil.c +++ b/kernel/sched/cpufreq_schedutil.c @@ -183,7 +183,11 @@ static void sugov_get_util(unsigned long *util, unsigned long *max, int cpu) cfs_max = arch_scale_cpu_capacity(NULL, cpu); - *util = min(rq->cfs.avg.util_avg, cfs_max); + *util = rq->cfs.avg.util_avg; + if (sched_feat(UTIL_EST)) + *util = max(*util, rq->cfs.util_est_runnable); + *util = min(*util, cfs_max); + *max = cfs_max; }