From patchwork Thu Nov 30 11:47:23 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Patrick Bellasi X-Patchwork-Id: 120148 Delivered-To: patch@linaro.org Received: by 10.140.22.227 with SMTP id 90csp559128qgn; Thu, 30 Nov 2017 03:48:18 -0800 (PST) X-Google-Smtp-Source: AGs4zMYQ/5WoSybFZDJyzeVPRUJxAFnhXmdPOCg00aSPfChL9meNfr0/km24yROCayqONAgxuhj1 X-Received: by 10.159.194.1 with SMTP id x1mr2407694pln.48.1512042498892; Thu, 30 Nov 2017 03:48:18 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1512042498; cv=none; d=google.com; s=arc-20160816; b=jZvR31mDu/0bvHe5A/KO30QTwYCAl9xdI7EFeLj4QkxBPU+X68T81l5R7nvD1BdfZD x9n2M0Ntd5/HCVbnqP43A1ffIU2T8Fgjbgfq60NvRqq/ZMTIRoenzjtrNvHO5Gu8SV6Q yFYUyST9znsK463CBrmiK4vlTV92wvcSEttwets5d82YY64h3t9n8bY+JG8lI7l3mEjt 1xfZHnsWwg9GelcB9bkqTcfFzh0xCx12ojb7nBPRLXkSBfOQYBfRhkus5tqAxrbd+N3w lKYDhNsEqmhLgr6JyFJCPYua7c9KChvymr83w+CH36oJ4IyoUlmHU9xXgsRhKum1knir ZCPg== 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=x18R921SGaIWHdwmFCuSjHzp43HDkAY77VjknIw5ZCM=; b=qNDhY/RGER8p0UIT8fb6gAgyB8KQUw8ENyfDq2h26tjpNEyf+Cua9PyJHgEdZSXsZ3 3MK3t9NqzmEmOHtYPFxumY48dqCSqRtxjLLNlj4tNBaSCPtjwa2acFy73cGFBuiATUkn 3DjB5imlyPsAdmi9aAS/7RJiS3pinsceQwWRV/ZuCBB7yzsdxYB1sOobpKKJCMoRHVLQ vOhdjIOLVAcebMWVaHqnoeazC+MIHJJHV8bcTVcW74K5dh32Idc51DqzVzw1zHS1l9GZ GbMy4pcMv1TEM0sejnOLFySazO+ZxkBX6cUycbSeTAF2DSw9NtkvC9eiwFUz+Eqbgtjt dkkQ== 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 y16si2890133pgc.589.2017.11.30.03.48.18; Thu, 30 Nov 2017 03:48:18 -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 S1752749AbdK3LsR (ORCPT + 26 others); Thu, 30 Nov 2017 06:48:17 -0500 Received: from foss.arm.com ([217.140.101.70]:51326 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752684AbdK3LsG (ORCPT ); Thu, 30 Nov 2017 06:48:06 -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 06E8E165C; Thu, 30 Nov 2017 03:48:06 -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 C47B43F236; Thu, 30 Nov 2017 03:48:03 -0800 (PST) From: Patrick Bellasi To: linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org Cc: Ingo Molnar , Peter Zijlstra , "Rafael J . Wysocki" , Viresh Kumar , Vincent Guittot , Dietmar Eggemann , Morten Rasmussen , Juri Lelli , Todd Kjos , Joel Fernandes Subject: [PATCH v3 6/6] cpufreq: schedutil: ignore sugov kthreads Date: Thu, 30 Nov 2017 11:47:23 +0000 Message-Id: <20171130114723.29210-7-patrick.bellasi@arm.com> X-Mailer: git-send-email 2.14.1 In-Reply-To: <20171130114723.29210-1-patrick.bellasi@arm.com> References: <20171130114723.29210-1-patrick.bellasi@arm.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In system where multiple CPUs shares the same frequency domain a small workload on a CPU can still be subject to frequency spikes, generated by the activation of the sugov's kthread. Since the sugov kthread is a special RT task, which goal is just that to activate a frequency transition, it does not make sense for it to bias the schedutil's frequency selection policy. This patch exploits the information related to the current task to silently ignore cpufreq_update_this_cpu() calls, coming from the RT scheduler, while the sugov kthread is running. Signed-off-by: Patrick Bellasi Reviewed-by: Dietmar Eggemann Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Rafael J. Wysocki Cc: Viresh Kumar Cc: linux-kernel@vger.kernel.org Cc: linux-pm@vger.kernel.org --- Changes from v2: - rebased on v4.15-rc1 - moved at the end of the stack since considered more controversial Changes from v1: - move check before policy spinlock (JuriL) Change-Id: I4d749458229b6496dd24a8c357be42cd35a739fd --- kernel/sched/cpufreq_schedutil.c | 8 ++++++++ 1 file changed, 8 insertions(+) -- 2.14.1 Reviewed-by: Juri Lelli diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c index 3eea8884e61b..a93ad5b0c40d 100644 --- a/kernel/sched/cpufreq_schedutil.c +++ b/kernel/sched/cpufreq_schedutil.c @@ -270,6 +270,10 @@ static void sugov_update_single(struct update_util_data *hook, u64 time, bool rt_mode; bool busy; + /* Skip updates generated by sugov kthreads */ + if (unlikely(current == sg_policy->thread)) + return; + sugov_set_iowait_boost(sg_cpu, time, flags); sg_cpu->last_update = time; @@ -356,6 +360,10 @@ static void sugov_update_shared(struct update_util_data *hook, u64 time, unsigned int next_f; bool rt_mode; + /* Skip updates generated by sugov kthreads */ + if (unlikely(current == sg_policy->thread)) + return; + raw_spin_lock(&sg_policy->update_lock); sugov_get_util(&util, &max, sg_cpu->cpu);