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Date:   Tue, 5 Jun 2018 17:31:05 +0200
From:   Juri Lelli <juri.lelli@redhat.com>
To:     Patrick Bellasi <patrick.bellasi@arm.com>
Cc:     Vincent Guittot <vincent.guittot@linaro.org>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        "open list:THERMAL" <linux-pm@vger.kernel.org>,
        Ingo Molnar <mingo@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        "Rafael J . Wysocki" <rafael.j.wysocki@intel.com>,
        Viresh Kumar <viresh.kumar@linaro.org>,
        Dietmar Eggemann <dietmar.eggemann@arm.com>,
        Morten Rasmussen <morten.rasmussen@arm.com>,
        Joel Fernandes <joelaf@google.com>,
        Steve Muckle <smuckle@google.com>, Todd Kjos <tkjos@google.com>
Subject: Re: [PATCH 2/2] sched/fair: util_est: add running_sum tracking
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On 05/06/18 16:11, Patrick Bellasi wrote:

[...]

> If I run an experiment with your example above, while using the
> performance governor to rule out any possible scale invariance
> difference, here is what I measure:
> 
>    Task1 (40ms delayed by the following Task2):
>                                mean          std     max
>       running_avg        455.387449    22.940168   492.0
>       util_avg           433.233288    17.395477   458.0
> 
>    Task2 (waking up at same time of Task1 and running before):
>                                mean          std     max
>       running_avg        430.281834    22.405175   455.0
>       util_avg           421.745331    22.098873   456.0
> 
> and if I compare Task1 above with another experiment where Task1 is
> running alone:
> 
>    Task1 (running alone):
>                                mean          std     min
>       running_avg        460.257895    22.103704   460.0
>       util_avg           435.119737    17.647556   461.0

Wait, why again in this last case running_avg != util_avg? :)