linux-kernel - Re: [PATCH v2] sched/fair: update scale invariance of PELT

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Date:   Tue, 11 Apr 2017 12:49:49 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Vincent Guittot <vincent.guittot@...aro.org>
Cc:     mingo@...nel.org, linux-kernel@...r.kernel.org,
        dietmar.eggemann@....com, Morten.Rasmussen@....com,
        yuyang.du@...el.com, pjt@...gle.com, bsegall@...gle.com
Subject: Re: [PATCH v2] sched/fair: update scale invariance of PELT


Lets go back to the unscaled version:

    running   idle
   |*********|---------|

With the current code, that would effectively end up like (again
assuming 50%):

    running   idle
   |*_*_*_*_*|---------|


Time stays the same, but we add extra idle cycles.