linux-kernel - Re: [PATCH v3 2/5] sched/fair: Skip update_blocked

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Message-ID: <CAKfTPtAQ3V6nRbrFfZCM7m+VteVwQi2o3k8Cqf9eGAKRBdwrvA@mail.gmail.com>
Date:   Thu, 21 Oct 2021 14:45:03 +0200
From:   Vincent Guittot <vincent.guittot@...aro.org>
To:     Mel Gorman <mgorman@...e.de>
Cc:     Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Juri Lelli <juri.lelli@...hat.com>,
        Dietmar Eggemann <dietmar.eggemann@....com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Ben Segall <bsegall@...gle.com>,
        Daniel Bristot de Oliveira <bristot@...hat.com>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        Tim Chen <tim.c.chen@...ux.intel.com>
Subject: Re: [PATCH v3 2/5] sched/fair: Skip update_blocked_averages if we are
 defering load balance

On Thu, 21 Oct 2021 at 11:44, Mel Gorman <mgorman@...e.de> wrote:
>
> On Tue, Oct 19, 2021 at 02:35:34PM +0200, Vincent Guittot wrote:
> > In newidle_balance(), the scheduler skips load balance to the new idle cpu
> > when the 1st sd of this_rq is:
> >
> >    this_rq->avg_idle < sd->max_newidle_lb_cost
> >
> > Doing a costly call to update_blocked_averages() will not be useful and
> > simply adds overhead when this condition is true.
> >
> > Check the condition early in newidle_balance() to skip
> > update_blocked_averages() when possible.
> >
> > Signed-off-by: Vincent Guittot <vincent.guittot@...aro.org>
> > Signed-off-by: Tim Chen <tim.c.chen@...ux.intel.com>
>
> The Signed-off-by seems to be in the wrong order but otherwise

The right signoff sequence should be:

Signed-off-by: Vincent Guittot <vincent.guittot@...aro.org>
Signed-off-by: Tim Chen <tim.c.chen@...ux.intel.com>
Signed-off-by: Vincent Guittot <vincent.guittot@...aro.org>

But I skipped the last one which was only a rebase and my signoff was
already there

>
> Acked-by: Mel Gorman <mgorman@...e.de>
>
> --
> Mel Gorman
> SUSE Labs