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From: Quentin Perret <qperret@google.com>
To: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: vincent.donnefort@arm.com, peterz@infradead.org,
	mingo@redhat.com, vincent.guittot@linaro.org,
	linux-kernel@vger.kernel.org, patrick.bellasi@matbug.net,
	valentin.schneider@arm.com
Subject: Re: [PATCH v2 1/2] sched/fair: Fix task utilization accountability in compute_energy()
Date: Thu, 25 Feb 2021 11:58:27 +0000	[thread overview]
Message-ID: <YDeQ47Kfh8s/B0cn@google.com> (raw)
In-Reply-To: <f2f5cf8e-3a0b-7192-5293-bad576e7066b@arm.com>

On Thursday 25 Feb 2021 at 12:45:06 (+0100), Dietmar Eggemann wrote:
> I.e. since _task_util_est is always >= task_util during wakeup, cpu_util
> must be > cpu_util_est (by more than _task_util_est - task_util).
> 
> I can see it for a CPU whose cpu_util has a fair amount of contributions
> from blocked tasks which cpu_util_est wouldn't have.

Yes I think this can manifest itself if there are tasks changing
behaviour, or on an idle CPU as its ue.enqueued will be 0 and we'll be
left with blocked util only.

Thanks,
Quentin

  reply	other threads:[~2021-02-25 11:59 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-25  8:36 [PATCH v2 0/2] Fix task utilization accountability for EAS vincent.donnefort
2021-02-25  8:36 ` [PATCH v2 1/2] sched/fair: Fix task utilization accountability in compute_energy() vincent.donnefort
2021-02-25  8:52   ` Quentin Perret
2021-02-25 11:45   ` Dietmar Eggemann
2021-02-25 11:58     ` Quentin Perret [this message]
2021-02-25 16:23     ` Vincent Donnefort
2021-03-02  9:01   ` [tip: sched/core] " tip-bot2 for Vincent Donnefort
2021-03-03  9:49   ` tip-bot2 for Vincent Donnefort
2021-03-06 11:42   ` tip-bot2 for Vincent Donnefort
2021-02-25  8:36 ` [PATCH v2 2/2] sched/fair: use lsub_positive in cpu_util_next() vincent.donnefort
2021-02-25  8:53   ` Quentin Perret
2021-02-25 11:46   ` Dietmar Eggemann
2021-03-02  9:01   ` [tip: sched/core] " tip-bot2 for Vincent Donnefort
2021-03-03  9:49   ` tip-bot2 for Vincent Donnefort
2021-03-06 11:42   ` tip-bot2 for Vincent Donnefort
2021-02-25 17:29 ` [PATCH v2 0/2] Fix task utilization accountability for EAS Peter Zijlstra

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