linux-kernel - Re: [PATCH 1/6] sched/fair: remove update of blocked load from newidle

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Message-ID: <8cea2836-aedd-0925-4359-a04c8e8729e6@arm.com>
Date:   Tue, 9 Feb 2021 14:44:33 +0100
From:   Dietmar Eggemann <dietmar.eggemann@....com>
To:     Vincent Guittot <vincent.guittot@...aro.org>, mingo@...hat.com,
        peterz@...radead.org, juri.lelli@...hat.com, rostedt@...dmis.org,
        bsegall@...gle.com, mgorman@...e.de, fweisbec@...il.com,
        tglx@...utronix.de, bristot@...hat.com,
        linux-kernel@...r.kernel.org, joel@...lfernandes.org
Cc:     qais.yousef@....com
Subject: Re: [PATCH 1/6] sched/fair: remove update of blocked load from
 newidle_balance

On 05/02/2021 12:48, Vincent Guittot wrote:
> newidle_balance runs with both preempt and irq disabled which prevent
> local irq to run during this period. The duration for updating of the
> blocked load of CPUs varies according to the number of cgroups and

Maybe s/number of cgroups/number of CPU cgroups with non-decayed
cfs_rq's (i.e. cfs_rq within the leaf cfs_rq list)

> extends this critical period to an uncontrolled level.
> 
> Remove the update from newidle_balance and trigger a normal ILB that
> will take care of the update instead.
> 
> Signed-off-by: Vincent Guittot <vincent.guittot@...aro.org>

otherwise, LGTM.

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