linux-kernel - Re: [PATCH] sched/debug: Add new tracepoints to track util

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Message-ID: <20200603121530.GB2570@hirez.programming.kicks-ass.net>
Date:   Wed, 3 Jun 2020 14:15:30 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Valentin Schneider <valentin.schneider@....com>
Cc:     vincent.donnefort@....com, mingo@...hat.com,
        vincent.guittot@...aro.org, linux-kernel@...r.kernel.org,
        patrick.bellasi@...bug.net, dietmar.eggemann@....com,
        qais.yousef@....com
Subject: Re: [PATCH] sched/debug: Add new tracepoints to track util_est

On Wed, Jun 03, 2020 at 01:04:26PM +0100, Valentin Schneider wrote:
> 
> On 27/05/20 17:39, vincent.donnefort@....com wrote:
> > From: Vincent Donnefort <vincent.donnefort@....com>
> >
> > The util_est signals are key elements for EAS task placement and
> > frequency selection. Having tracepoints to track these signals enables
> > load-tracking and schedutil testing and/or debugging by a toolkit.
> >
> > Signed-off-by: Vincent Donnefort <vincent.donnefort@....com>
> >
> 
> To put it more bluntly, we can't really do task placement / load tracking
> testing if util_est is enabled (which reminds me we may want to get rid of
> the SCHED_FEAT at some point, it's been default on since ~v4.17), since
> there can be noticeable gaps between util_avg and util_est.
> 
> Reviewed-by: Valentin Schneider <valentin.schneider@....com>

Thanks!