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=-10.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,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 04518C433DB for ; Tue, 23 Feb 2021 14:49:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B454864E58 for ; Tue, 23 Feb 2021 14:49:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233098AbhBWOsu (ORCPT ); Tue, 23 Feb 2021 09:48:50 -0500 Received: from foss.arm.com ([217.140.110.172]:53836 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232553AbhBWOsj (ORCPT ); Tue, 23 Feb 2021 09:48:39 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 9F4961FB; Tue, 23 Feb 2021 06:47:53 -0800 (PST) Received: from [192.168.178.6] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 29A643F73B; Tue, 23 Feb 2021 06:47:52 -0800 (PST) Subject: Re: [PATCH] sched/fair: Fix task utilization accountability in cpu_util_next() To: Quentin Perret , Vincent Donnefort Cc: peterz@infradead.org, mingo@redhat.com, vincent.guittot@linaro.org, linux-kernel@vger.kernel.org, patrick.bellasi@matbug.net, valentin.schneider@arm.com References: <20210222095401.37158-1-vincent.donnefort@arm.com> <20210222113602.GA286874@e120877-lin.cambridge.arm.com> <20210222150151.GA124800@e124901.cambridge.arm.com> From: Dietmar Eggemann Message-ID: Date: Tue, 23 Feb 2021 15:47:42 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 22/02/2021 17:23, Quentin Perret wrote: > On Monday 22 Feb 2021 at 15:58:56 (+0000), Quentin Perret wrote: >> But in any case, if we're going to address this, I'm still not sure this >> patch will be what we want. As per my first comment we need to keep the >> frequency estimation right. > > Totally untested, but I think in principle you would like something like > the snippet below. Would that work? > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index 04a3ce20da67..6594d875c6ac 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -6534,8 +6534,13 @@ compute_energy(struct task_struct *p, int dst_cpu, struct perf_domain *pd) > * its pd list and will not be accounted by compute_energy(). > */ > for_each_cpu_and(cpu, pd_mask, cpu_online_mask) { > - unsigned long cpu_util, util_cfs = cpu_util_next(cpu, p, dst_cpu); > + unsigned long util_freq = cpu_util_next(cpu, p, dst_cpu); > + unsigned long util_running = cpu_util_without(cpu, p); Wouldn't this be the same as: unsigned long util_running = cpu_util_next(cpu, p, -1); except some different handling of !last_update_time and 'task_on_rq_queued(p) || current == p)' in cpu_util_without() which shouldn't happen in EAS. We have quite a lot of util related functions! [...]