linux-kernel - Re: [PATCH v5 10/14] sched/cpufreq: Refactor the utilization aggregation method

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Message-ID: <20180802124511.GN2512@hirez.programming.kicks-ass.net>
Date:   Thu, 2 Aug 2018 14:45:11 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     skannan@...eaurora.org
Cc:     Quentin Perret <quentin.perret@....com>, rjw@...ysocki.net,
        linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        gregkh@...uxfoundation.org, mingo@...hat.com,
        dietmar.eggemann@....com, morten.rasmussen@....com,
        chris.redpath@....com, patrick.bellasi@....com,
        valentin.schneider@....com, vincent.guittot@...aro.org,
        thara.gopinath@...aro.org, viresh.kumar@...aro.org,
        tkjos@...gle.com, joel@...lfernandes.org, smuckle@...gle.com,
        adharmap@...cinc.com, skannan@...cinc.com, pkondeti@...eaurora.org,
        juri.lelli@...hat.com, edubezval@...il.com,
        srinivas.pandruvada@...ux.intel.com, currojerez@...eup.net,
        javi.merino@...nel.org, linux-pm-owner@...r.kernel.org
Subject: Re: [PATCH v5 10/14] sched/cpufreq: Refactor the utilization
 aggregation method

On Thu, Aug 02, 2018 at 02:33:15PM +0200, Peter Zijlstra wrote:
> On Mon, Jul 30, 2018 at 12:35:27PM -0700, skannan@...eaurora.org wrote:
> > On 2018-07-24 05:25, Quentin Perret wrote:
> > If it's going to be a different aggregation from what's done for frequency
> > guidance, I don't see the point of having this inside schedutil. Why not
> > keep it inside the scheduler files? Also, it seems weird to use a governor's
> > code when it might not actually be in use. What if someone is using
> > ondemand, conservative, performance, etc?
> 
> EAS hard relies on schedutil -- I suppose we need a check for that
> somewhere and maybe some infrastructure to pin the cpufreq governor.

Either that or disable EAS when another governor is selected.

> We're simply not going to support it for anything else.

To clarify, it makes absolutely no sense what so ever to attempt EAS
when the DVFS control is not coordinated.