Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756201AbdLVLCS (ORCPT ); Fri, 22 Dec 2017 06:02:18 -0500 Received: from foss.arm.com ([217.140.101.70]:44974 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750786AbdLVLCP (ORCPT ); Fri, 22 Dec 2017 06:02:15 -0500 Date: Fri, 22 Dec 2017 11:02:06 +0000 From: Patrick Bellasi To: Peter Zijlstra Cc: Juri Lelli , linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, Ingo Molnar , "Rafael J . Wysocki" , Viresh Kumar , Vincent Guittot , Dietmar Eggemann , Morten Rasmussen , Todd Kjos , Joel Fernandes Subject: Re: [PATCH v3 0/6] cpufreq: schedutil: fixes for flags updates Message-ID: <20171222110206.GA6414@e110439-lin> References: <20171130114723.29210-1-patrick.bellasi@arm.com> <20171220153029.dqrtjbyowhqdl56r@hirez.programming.kicks-ass.net> <20171220173814.GC22246@localhost.localdomain> <20171222100626.7g5yklspjofcp2we@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20171222100626.7g5yklspjofcp2we@hirez.programming.kicks-ass.net> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2004 Lines: 61 On 22-Dec 11:06, Peter Zijlstra wrote: > On Wed, Dec 20, 2017 at 06:38:14PM +0100, Juri Lelli wrote: > > On 20/12/17 16:30, Peter Zijlstra wrote: > > > > [...] > > > > > @@ -327,12 +331,7 @@ static unsigned int sugov_next_freq_shar > > > if (delta_ns > TICK_NSEC) { > > > j_sg_cpu->iowait_boost = 0; > > > j_sg_cpu->iowait_boost_pending = false; > > > - j_sg_cpu->util_cfs = 0; > > > - if (j_sg_cpu->util_dl == 0) > > > - continue; > > > } > > > > This goes away because with Brendan/Vincent fix we don't need the > > workaround for stale CFS util contribution for idle CPUs anymore? > > An easy fix would be something like the below I suppose (also folded a > change from Viresh). > > This way it completely ignores the demand from idle CPUs. Which I > suppose is exactly what you want, no? > > diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c > index ab84d2261554..9736b537386a 100644 > --- a/kernel/sched/cpufreq_schedutil.c > +++ b/kernel/sched/cpufreq_schedutil.c > @@ -315,8 +315,8 @@ static unsigned int sugov_next_freq_shared(struct sugov_cpu *sg_cpu, u64 time) > unsigned long j_util, j_max; > s64 delta_ns; > > - if (j_sg_cpu != sg_cpu) > - sugov_get_util(j_sg_cpu); > + if (idle_cpu(j)) > + continue; That should work to skip IDLE CPUs... however I'm missing where now we get the sugov_get_util(j_sg_cpu) for active CPUs. It has been moved somewhere else I guess... Moreover, that way don't we completely disregard CFS blocked load for IDLE CPUs... as well as DL reserved utilization, which should be released only at the 0-lag time? > > /* > * If the CFS CPU utilization was last updated before the > @@ -354,7 +354,6 @@ static void sugov_update_shared(struct update_util_data *hook, u64 time, > > raw_spin_lock(&sg_policy->update_lock); > > - sugov_get_util(sg_cpu); > sugov_set_iowait_boost(sg_cpu, time, flags); > sg_cpu->last_update = time; > -- #include Patrick Bellasi