Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755110AbbHQMTS (ORCPT ); Mon, 17 Aug 2015 08:19:18 -0400 Received: from eu-smtp-delivery-143.mimecast.com ([207.82.80.143]:64619 "EHLO eu-smtp-delivery-143.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754631AbbHQMTQ convert rfc822-to-8bit (ORCPT ); Mon, 17 Aug 2015 08:19:16 -0400 Message-ID: <55D1D16F.1070106@arm.com> Date: Mon, 17 Aug 2015 13:19:59 +0100 From: Juri Lelli User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Peter Zijlstra , Michael Turquette CC: Morten Rasmussen , "mingo@redhat.com" , "vincent.guittot@linaro.org" , "daniel.lezcano@linaro.org" , Dietmar Eggemann , "yuyang.du@intel.com" , "rjw@rjwysocki.net" , "sgurrappadi@nvidia.com" , "pang.xunlei@zte.com.cn" , "linux-kernel@vger.kernel.org" , "linux-pm@vger.kernel.org" Subject: Re: [RFCv5 PATCH 40/46] sched/cpufreq_sched: compute freq_new based on capacity_orig_of() References: <1436293469-25707-1-git-send-email-morten.rasmussen@arm.com> <1436293469-25707-41-git-send-email-morten.rasmussen@arm.com> <20150815124638.GG10304@worktop.programming.kicks-ass.net> <20150816040333.31346.22542@quantum> <20150816202401.GJ10304@worktop.programming.kicks-ass.net> In-Reply-To: <20150816202401.GJ10304@worktop.programming.kicks-ass.net> X-OriginalArrivalTime: 17 Aug 2015 12:19:13.0645 (UTC) FILETIME=[EDBDA1D0:01D0D8E6] X-MC-Unique: SvZ10lz9TzypzvXyelyAsg-1 Content-Type: text/plain; charset=WINDOWS-1252 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1758 Lines: 46 On 16/08/15 21:24, Peter Zijlstra wrote: > On Sat, Aug 15, 2015 at 09:03:33PM -0700, Michael Turquette wrote: >> Quoting Peter Zijlstra (2015-08-15 05:46:38) >>> On Tue, Jul 07, 2015 at 07:24:23PM +0100, Morten Rasmussen wrote: >>>> diff --git a/kernel/sched/cpufreq_sched.c b/kernel/sched/cpufreq_sched.c >>>> index 2968f3a..7071528 100644 >>>> --- a/kernel/sched/cpufreq_sched.c >>>> +++ b/kernel/sched/cpufreq_sched.c >>>> @@ -184,7 +184,7 @@ void cpufreq_sched_set_cap(int cpu, unsigned long capacity) >>>> goto out; >>>> >>>> /* Convert the new maximum capacity request into a cpu frequency */ >>>> - freq_new = capacity * policy->max >> SCHED_CAPACITY_SHIFT; >>>> + freq_new = (capacity * policy->max) / capacity_orig_of(cpu); >>>> >>>> /* No change in frequency? Bail and return current capacity. */ >>>> if (freq_new == policy->cur) >>> >>> Can't we avoid exporting that lot by simply passing in the right values >>> to begin with? >> >> By "right value" do you mean, "pass the frequency from cfs"? > > Nah, just maybe: (capacity << SCHED_CAPACITY_SHIFT) / capacity_orig_of() > such that you don't have to export that knowledge to this thing. > Oh, right. I guess we can just go with something like: req_cap = get_cpu_usage(cpu) * capacity_margin / capacity_orig_of(cpu); on fair.c side and switch back to freq_new = capacity * policy->max >> SCHED_CAPACITY_SHIFT; on cpufreq_sched.c side. That saves us exporting capacity_orig_of(). Thanks, - Juri -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/