From mboxrd@z Thu Jan 1 00:00:00 1970 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=-8.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 64348C17440 for ; Tue, 12 Nov 2019 15:05:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3505321925 for ; Tue, 12 Nov 2019 15:05:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="f78JwAVh" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726970AbfKLPFx (ORCPT ); Tue, 12 Nov 2019 10:05:53 -0500 Received: from mail-wm1-f65.google.com ([209.85.128.65]:37688 "EHLO mail-wm1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726980AbfKLPFw (ORCPT ); Tue, 12 Nov 2019 10:05:52 -0500 Received: by mail-wm1-f65.google.com with SMTP id b17so3325297wmj.2 for ; Tue, 12 Nov 2019 07:05:48 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:content-transfer-encoding:in-reply-to :user-agent; bh=+tyvV/5E996LDIHsndVKgQTT2nmYBAp+8tJn3tDeXsQ=; b=f78JwAVh8m3qh6NShS2kfGB+l5WgYxgRHV35SHkXE1PklwA5nVSF4r5xxM8FTSxf1J 4+/53rGDs9v5RZ8stsxDWZHQw1eO248RJU7v06AY9MBn7nbzMvH4BEyYypbED4ba/lLK RqvuzsrzI0DkdUsw5r0tD2d8uZ2D3ChhszQjyT9Znem7nAwJRgznP128qlZtOSCA4wPF bSxoEWIv6wkL2USXfRcIq6Y7OCtfNXgYTbAo66X0W/LtY1VDYGgtlciDHIdkKpjPwICZ K1miVosbXCkopdxsGsch5Ua0Z08/8iXeORvuL35FMSRhA7wiiG16qJqyjPEnoy8m4HM1 98Pw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:content-transfer-encoding :in-reply-to:user-agent; bh=+tyvV/5E996LDIHsndVKgQTT2nmYBAp+8tJn3tDeXsQ=; b=loCsclbCK523k1ToYV7kBU+xPnD73OwT0cZPAva+Ad/Zp3CmPmooVUhUpddUO8Z8Hl rKHxs60WRgJcXVil7YC6I/6C30MzHSGW2GmaDDjPXW92lUzHsiDbhWUZJIc2qqbpRPf5 5nFIRYjVLd0m2Im6Ir5i/YdBK85JrYSgt5TW9kDBZoMc/Twg2NcnIrCVr51+jeMAh1/N SPNsrbHLaOxNz7nuzHxmxM0Cne/lrEM9SNzZLKHE88QxNyow/wN/4Nsev4iEfr0Po0g7 6dVi+1SBdHud8XDWt6owCLV8wonmwe1s8LvXaGDuqQXgSC5z4bIx0CJceOJE6vfyo+R5 b87g== X-Gm-Message-State: APjAAAWBQraW+8AYtsl1HPEgTzGBgA9IY1zEaAnQUe17Q6MSsCrb+rZd xwraR5Sd5EGoNY2ytbMfk97Xxg== X-Google-Smtp-Source: APXvYqxa+x5eG33cvaM0b8URg3VOtBVZUa/SJNjueQfR6wOQzh2Lw1y4I/Q0+z7SMr3SnUkHaW17Aw== X-Received: by 2002:a05:600c:214b:: with SMTP id v11mr4557023wml.149.1573571147460; Tue, 12 Nov 2019 07:05:47 -0800 (PST) Received: from linaro.org ([2a01:e0a:f:6020:e45f:4180:5590:a312]) by smtp.gmail.com with ESMTPSA id r15sm42364990wrc.5.2019.11.12.07.05.45 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 12 Nov 2019 07:05:46 -0800 (PST) Date: Tue, 12 Nov 2019 16:05:44 +0100 From: Vincent Guittot To: linux-kernel@vger.kernel.org, mingo@redhat.com, peterz@infradead.org, dietmar.eggemann@arm.com, juri.lelli@redhat.com, rostedt@goodmis.org, mgorman@suse.de, dsmythies@telus.net Cc: linux-pm@vger.kernel.org, torvalds@linux-foundation.org, tglx@linutronix.de, sargun@sargun.me, tj@kernel.org, xiexiuqi@huawei.com, xiezhipeng1@huawei.com, srinivas.pandruvada@linux.intel.com Subject: Re: [PATCH v2] sched/freq: move call to cpufreq_update_util Message-ID: <20191112150544.GA3664@linaro.org> References: <1573570093-1340-1-git-send-email-vincent.guittot@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1573570093-1340-1-git-send-email-vincent.guittot@linaro.org> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org Le Tuesday 12 Nov 2019 à 15:48:13 (+0100), Vincent Guittot a écrit : > update_cfs_rq_load_avg() calls cfs_rq_util_change() everytime pelt decays, > which might be inefficient when cpufreq driver has rate limitation. > > When a task is attached on a CPU, we have call path: > > update_blocked_averages() > update_cfs_rq_load_avg() > cfs_rq_util_change -- > trig frequency update > attach_entity_load_avg() > cfs_rq_util_change -- > trig frequency update > > The 1st frequency update will not take into account the utilization of the > newly attached task and the 2nd one might be discard because of rate > limitation of the cpufreq driver. > > update_cfs_rq_load_avg() is only called by update_blocked_averages() > and update_load_avg() so we can move the call to > {cfs_rq,cpufreq}_util_change() into these 2 functions. It's also > interesting to notice that update_load_avg() already calls directly > cfs_rq_util_change() for !SMP case. > > This changes will also ensure that cpufreq_update_util() is called even > when there is no more CFS rq in the leaf_cfs_rq_list to update but only > irq, rt or dl pelt signals. > > Reported-by: Doug Smythies > Fixes: 039ae8bcf7a5 ("sched/fair: Fix O(nr_cgroups) in the load balancing path") > Signed-off-by: Vincent Guittot > > --- > > I have just rebased the patch on latest tip/sched/core and made it a proper > patchset after Doug reported that the problem has diseappeared according to > his 1st results but tests results are not all based on the same v5.4-rcX > and with menu instead of teo governor. > > kernel/sched/fair.c | 33 +++++++++++++++++++++------------ > 1 file changed, 21 insertions(+), 12 deletions(-) > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index e458f52..c93d534 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -3508,9 +3508,6 @@ update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq) > cfs_rq->load_last_update_time_copy = sa->last_update_time; > #endif > > - if (decayed) > - cfs_rq_util_change(cfs_rq, 0); > - > return decayed; > } > > @@ -3620,8 +3617,12 @@ static inline void update_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s > attach_entity_load_avg(cfs_rq, se, SCHED_CPUFREQ_MIGRATION); > update_tg_load_avg(cfs_rq, 0); > > - } else if (decayed && (flags & UPDATE_TG)) > - update_tg_load_avg(cfs_rq, 0); > + } else if (decayed) { > + cfs_rq_util_change(cfs_rq, 0); > + > + if (flags & UPDATE_TG) > + update_tg_load_avg(cfs_rq, 0); > + } > } > > #ifndef CONFIG_64BIT > @@ -7484,6 +7485,7 @@ static void update_blocked_averages(int cpu) > const struct sched_class *curr_class; > struct rq_flags rf; > bool done = true; > + int decayed = 0; > > rq_lock_irqsave(rq, &rf); > update_rq_clock(rq); > @@ -7493,9 +7495,9 @@ static void update_blocked_averages(int cpu) > * that RT, DL and IRQ signals have been updated before updating CFS. > */ > curr_class = rq->curr->sched_class; > - update_rt_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &rt_sched_class); > - update_dl_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &dl_sched_class); > - update_irq_load_avg(rq, 0); > + decayed |= update_rt_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &rt_sched_class); > + decayed |= update_dl_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &dl_sched_class); > + decayed |= update_irq_load_avg(rq, 0); > > /* Don't need periodic decay once load/util_avg are null */ > if (others_have_blocked(rq)) > @@ -7529,6 +7531,9 @@ static void update_blocked_averages(int cpu) > } > > update_blocked_load_status(rq, !done); > + > + if (decayed) > + cpufreq_update_util(rq, 0); > rq_unlock_irqrestore(rq, &rf); > } > > @@ -7585,6 +7590,7 @@ static inline void update_blocked_averages(int cpu) > struct cfs_rq *cfs_rq = &rq->cfs; > const struct sched_class *curr_class; > struct rq_flags rf; > + int decayed = 0; > > rq_lock_irqsave(rq, &rf); > update_rq_clock(rq); > @@ -7594,13 +7600,16 @@ static inline void update_blocked_averages(int cpu) > * that RT, DL and IRQ signals have been updated before updating CFS. > */ > curr_class = rq->curr->sched_class; > - update_rt_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &rt_sched_class); > - update_dl_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &dl_sched_class); > - update_irq_load_avg(rq, 0); > + decayed |= update_rt_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &rt_sched_class); > + decayed |= update_dl_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &dl_sched_class); > + decayed |= update_irq_load_avg(rq, 0); > > - update_cfs_rq_load_avg(cfs_rq_clock_pelt(cfs_rq), cfs_rq); > + decayed |= update_cfs_rq_load_avg(cfs_rq_clock_pelt(cfs_rq), cfs_rq); > > update_blocked_load_status(rq, cfs_rq_has_blocked(cfs_rq) || others_have_blocked(rq)); > + > + if (decayed) > + cpufreq_update_util(rq, 0); > rq_unlock_irqrestore(rq, &rf); > } > > -- > 2.7.4 >