linux-kernel - Re: [PATCH] sched/fair: Clear SMT siblings after determining the core is not idle

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Message-ID: <20201201110300.GR3040@hirez.programming.kicks-ass.net>
Date:   Tue, 1 Dec 2020 12:03:00 +0100
From:   Peter Zijlstra <peterz@...radead.org>
To:     Vincent Guittot <vincent.guittot@...aro.org>
Cc:     Mel Gorman <mgorman@...hsingularity.net>,
        Ingo Molnar <mingo@...hat.com>,
        "Li, Aubrey" <aubrey.li@...ux.intel.com>,
        Valentin Schneider <valentin.schneider@....com>,
        linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] sched/fair: Clear SMT siblings after determining the
 core is not idle

On Mon, Nov 30, 2020 at 03:47:01PM +0100, Vincent Guittot wrote:
> On Mon, 30 Nov 2020 at 15:40, Mel Gorman <mgorman@...hsingularity.net> wrote:
> >
> > The clearing of SMT siblings from the SIS mask before checking for an idle
> > core is a small but unnecessary cost. Defer the clearing of the siblings
> > until the scan moves to the next potential target. The cost of this was
> > not measured as it is borderline noise but it should be self-evident.
> 
> Good point
> 
> >
> > Signed-off-by: Mel Gorman <mgorman@...hsingularity.net>
> 
> Reviewed-by: Vincent Guittot <vincent.guittot@...aro.org>

Thanks!