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=-2.1 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID, USER_AGENT_MUTT 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 D0536C6778F for ; Mon, 9 Jul 2018 12:02:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7E9552089B for ; Mon, 9 Jul 2018 12:02:16 +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="Y3+8Q7Fn" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7E9552089B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932601AbeGIMCN (ORCPT ); Mon, 9 Jul 2018 08:02:13 -0400 Received: from merlin.infradead.org ([205.233.59.134]:52118 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754475AbeGIMCL (ORCPT ); Mon, 9 Jul 2018 08:02:11 -0400 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=WdwxYOOqHukeqDKuuSDwuBritD59EzgJzVrzckMW3ss=; b=Y3+8Q7FnA+5e6vbdfmAs5j93l hdCp2m/EQhDKE7Cgke/Q/tn56HSbaJatH9nES2IcM/szbmSSJ+CQkj59xReNObgdD3CG1mFbkknKF AsOFsAJfMdskgens9Hvb/m8IqakDS4TK9ufENI7aP/19Cbuwh1nWQQwqaeeLulXn7blzpFJxXtk+S jMgu5KCjnF+lFy8u7m0LJ7D36Ta4q21zvpLpZlwz74biFultbsEwsiordZEmH0Umb4njPXV52EXGp MfbjiYXmV4KH1s5TrqHS+BXFTf+ZaH74qcNZj0Ij0SizahCas4p9K1C4DjK2nY5XVn0TLifDubMJz OL4JDoomg==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1fcUrN-0008Fu-Bs; Mon, 09 Jul 2018 12:01:41 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id E8D892029764D; Mon, 9 Jul 2018 14:01:38 +0200 (CEST) Date: Mon, 9 Jul 2018 14:01:38 +0200 From: Peter Zijlstra To: Quentin Perret Cc: rjw@rjwysocki.net, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, gregkh@linuxfoundation.org, mingo@redhat.com, dietmar.eggemann@arm.com, morten.rasmussen@arm.com, chris.redpath@arm.com, patrick.bellasi@arm.com, valentin.schneider@arm.com, vincent.guittot@linaro.org, thara.gopinath@linaro.org, viresh.kumar@linaro.org, tkjos@google.com, joel@joelfernandes.org, smuckle@google.com, adharmap@quicinc.com, skannan@quicinc.com, pkondeti@codeaurora.org, juri.lelli@redhat.com, edubezval@gmail.com, srinivas.pandruvada@linux.intel.com, currojerez@riseup.net, javi.merino@kernel.org Subject: Re: [RFC PATCH v4 09/12] sched/fair: Introduce an energy estimation helper function Message-ID: <20180709120138.GQ2494@hirez.programming.kicks-ass.net> References: <20180628114043.24724-1-quentin.perret@arm.com> <20180628114043.24724-10-quentin.perret@arm.com> <20180706131243.GV2458@hirez.programming.kicks-ass.net> <20180706151212.GD17577@e108498-lin.cambridge.arm.com> <20180706154949.GO2494@hirez.programming.kicks-ass.net> <20180706170443.GE17577@e108498-lin.cambridge.arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180706170443.GE17577@e108498-lin.cambridge.arm.com> User-Agent: Mutt/1.10.0 (2018-05-17) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jul 06, 2018 at 06:04:44PM +0100, Quentin Perret wrote: > 'max_util' is basically the util we use to request an OPP. 'sum_util' is > how long the CPUs will be running. A indeed. But yes bit of a mess, but it wants doing I think. Perhaps a little something like the below... The alternative is two separate but closely related functions, not sure which is better. enum schedutil_type { frequency_util, energy_util, }; unsigned long schedutil_freq_util(int cpu, unsigned long util_cfs, enum schedutil_type type) { struct rq *rq = cpu_rq(cpu); unsigned long util, irq, max; max = arch_scale_cpu_capacity(NULL, cpu); if (type == frequency_util && rt_rq_is_runnable(&rq->rt)) return max; /* * Early check to see if IRQ/steal time saturates the CPU, can be * because of inaccuracies in how we track these -- see * update_irq_load_avg(). */ irq = cpu_util_irq(rq); if (unlikely(irq >= max)) return max; /* * Because the time spend on RT/DL tasks is visible as 'lost' time to * CFS tasks and we use the same metric to track the effective * utilization (PELT windows are synchronized) we can directly add them * to obtain the CPU's actual utilization. */ util = util_cfs; util += cpu_util_rt(rq); if (type == frequency_util) { /* * For frequency selection we do not make cpu_util_dl() * a permanent part of this sum because we want to use * cpu_bw_dl() later on, but we need to check if the * CFS+RT+DL sum is saturated (ie. no idle time) such * that we select f_max when there is no idle time. * * NOTE: numerical errors or stop class might cause us * to not quite hit saturation when we should -- * something for later. */ if ((util + cpu_util_dl(rq)) >= max) return max; } else { /* * OTOH, for energy computation we need the estimated * running time, so include util_dl and ignore dl_bw. */ util += cpu_util_dl(rq); if (util >= max) return max; } /* * There is still idle time; further improve the number by using the * irq metric. Because IRQ/steal time is hidden from the task clock we * need to scale the task numbers: * * 1 - irq * U' = irq + ------- * U * max */ util *= (max - irq); util /= max; util += irq; if (type == frequency_util) { /* * Bandwidth required by DEADLINE must always be granted * while, for FAIR and RT, we use blocked utilization of * IDLE CPUs as a mechanism to gracefully reduce the * frequency when no tasks show up for longer periods of * time. * * Ideally we would like to set bw_dl as min/guaranteed * freq and util + bw_dl as requested freq. However, * cpufreq is not yet ready for such an interface. So, * we only do the latter for now. */ util += cpu_bw_dl(rq); } return min(max, util); }