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=-5.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 F09A7C432C3 for ; Fri, 15 Nov 2019 15:13:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BC58E20733 for ; Fri, 15 Nov 2019 15:13:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="Lz5ZvFoc" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727412AbfKOPNB (ORCPT ); Fri, 15 Nov 2019 10:13:01 -0500 Received: from merlin.infradead.org ([205.233.59.134]:33266 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727380AbfKOPNA (ORCPT ); Fri, 15 Nov 2019 10:13:00 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=OQdTLuR4MwzJvC3l2K9WiOBsfhChWetXzjSMuUMUuxA=; b=Lz5ZvFoc56/6mRaBw91xDfNB/ CmlEBZP5nqpX6wKCTXRhgE5vSEBZCqqFIPZ4AwqnWXX57UpifP7lQy2xDjnpTpfAU0cowXh0bGagZ rEt9gGXBqdWShK9pmYTMdk1kxDjVrttwv0gBUGyIO0zfhKqBg7LXgKPRqYaj+pIftpcZtmdFIzHRV QMj+tmg8JgRh07j8ho30bQcth84zOvAGhWSDUmBZjq92EgcfWvxbSjPw0Dqgdw+iYD+5ulPSBD9c/ gXOZRz1aqW+hSXOgbBH7B3agMwvkCi9L5LihNef3Z+vjsdpAs/wuNlCqoQFivk2E1hvjZNwTjaC91 ZwxpaE/UQ==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1iVdGq-0000YK-3Q; Fri, 15 Nov 2019 15:12:24 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id A5CB9303DDD; Fri, 15 Nov 2019 16:11:12 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id C8E352B12EE0A; Fri, 15 Nov 2019 16:12:20 +0100 (CET) Date: Fri, 15 Nov 2019 16:12:20 +0100 From: Peter Zijlstra To: Vincent Guittot Cc: linux-kernel , Ingo Molnar , Dietmar Eggemann , Juri Lelli , Steven Rostedt , Mel Gorman , Doug Smythies , "open list:THERMAL" , Linus Torvalds , Thomas Gleixner , Sargun Dhillon , Tejun Heo , Xie XiuQi , xiezhipeng1@huawei.com, Srinivas Pandruvada Subject: Re: [PATCH v4] sched/freq: move call to cpufreq_update_util Message-ID: <20191115151220.GO4131@hirez.programming.kicks-ass.net> References: <1573751251-3505-1-git-send-email-vincent.guittot@linaro.org> <20191115132520.GJ4131@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org On Fri, Nov 15, 2019 at 02:37:27PM +0100, Vincent Guittot wrote: > On Fri, 15 Nov 2019 at 14:25, Peter Zijlstra wrote: > > Should not all 3 have their windows aligned and thus alway return the > > exact same value? > > rt and dl yes but not irq > > But having aligned window doesn't mean that they will all decay. > One can have been updated just before (during a dequeue as an example) > or at least less than 1ms before Now, the thing is, if that update happened in sched/rt, then it wouldn't have called cpufreq anyway. And once we're idle longer than a period, they'll all decay at once. Except indeed that IRQ stuff, which runs out of sync. That is, I'm just not convinced it matters much if we keep rq->cfs on the list forever (like UP). Because we'll only stop calling when update_blocked_averages() when everything hit 0, and up until that point, we'll get one update per period from rq->cfs. For good measure we can force an update when @done, at that point we know all 0s. How is something like this? --- diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 545bcb90b4de..a99ac2aa4a23 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 @@ -7453,7 +7454,7 @@ static void update_blocked_averages(int cpu) struct cfs_rq *cfs_rq, *pos; const struct sched_class *curr_class; struct rq_flags rf; - bool done = true; + bool done = true, decayed = false; rq_lock_irqsave(rq, &rf); update_rq_clock(rq); @@ -7476,10 +7477,14 @@ static void update_blocked_averages(int cpu) * list_add_leaf_cfs_rq() for details. */ for_each_leaf_cfs_rq_safe(rq, cfs_rq, pos) { + bool last = cfs_rq == &rq->cfs; struct sched_entity *se; - if (update_cfs_rq_load_avg(cfs_rq_clock_pelt(cfs_rq), cfs_rq)) + if (update_cfs_rq_load_avg(cfs_rq_clock_pelt(cfs_rq), cfs_rq)) { update_tg_load_avg(cfs_rq, 0); + if (last) + decayed = true; + } /* Propagate pending load changes to the parent, if any: */ se = cfs_rq->tg->se[cpu]; @@ -7490,7 +7495,7 @@ static void update_blocked_averages(int cpu) * There can be a lot of idle CPU cgroups. Don't let fully * decayed cfs_rqs linger on the list. */ - if (cfs_rq_is_decayed(cfs_rq)) + if (!last && cfs_rq_is_decayed(cfs_rq)) list_del_leaf_cfs_rq(cfs_rq); /* Don't need periodic decay once load/util_avg are null */ @@ -7498,6 +7503,9 @@ static void update_blocked_averages(int cpu) done = false; } + if (decayed || done) + cpufreq_update_util(rq, 0); + update_blocked_load_status(rq, !done); rq_unlock_irqrestore(rq, &rf); } @@ -7555,6 +7563,7 @@ 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; + bool done, decayed; rq_lock_irqsave(rq, &rf); update_rq_clock(rq); @@ -7568,9 +7577,13 @@ static inline void update_blocked_averages(int cpu) update_dl_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &dl_sched_class); 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); + done = !(cfs_rq_has_blocked(cfs_rq) || others_have_blocked(rq)); - update_blocked_load_status(rq, cfs_rq_has_blocked(cfs_rq) || others_have_blocked(rq)); + if (decayed || done) + cpufreq_update_util(rq, 0); + + update_blocked_load_status(rq, !done); rq_unlock_irqrestore(rq, &rf); }