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

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Message-ID: <20211021094412.GC3891@suse.de>
Date:   Thu, 21 Oct 2021 10:44:12 +0100
From:   Mel Gorman <mgorman@...e.de>
To:     Vincent Guittot <vincent.guittot@...aro.org>
Cc:     mingo@...hat.com, peterz@...radead.org, juri.lelli@...hat.com,
        dietmar.eggemann@....com, rostedt@...dmis.org, bsegall@...gle.com,
        bristot@...hat.com, linux-kernel@...r.kernel.org,
        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 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

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

-- 
Mel Gorman
SUSE Labs