linux-kernel - Re: [PATCH] sched/fair: Rearrange select_task_rq

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Message-ID: <0985e709-0d71-2c08-20a9-7bfb618fb5f2@arm.com>
Date:   Tue, 24 Apr 2018 12:19:07 +0100
From:   Valentin Schneider <valentin.schneider@....com>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     Viresh Kumar <viresh.kumar@...aro.org>,
        Ingo Molnar <mingo@...hat.com>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        linux-kernel@...r.kernel.org,
        Quentin Perret <quentin.perret@....com>
Subject: Re: [PATCH] sched/fair: Rearrange select_task_rq_fair() to optimize
 it

On 24/04/18 11:43, Peter Zijlstra wrote:
> On Tue, Apr 24, 2018 at 11:02:26AM +0100, Valentin Schneider wrote:
>> I'd argue making things easier to read is a non-negligible part as well.
> 
> Right, so I don't object to either of these (I think); but it would be
> good to see this in combination with that proposed EAS change.
> 

True, I would've said the call to find_energy_efficient_cpu() ([1]) could
simply be added to the if (sd) {} case, but...

> I think you (valentin) wanted to side-step the entire domain loop in
> that case or something.
> 

...this would change more things. Admittedly I've been sort of out of the loop
(no pun intended) lately, but this doesn't ring a bell. That might have been
the other frenchie (Quentin) :)

> But yes, getting this code more readable is defninitely useful.
> 

[1]: See [RFC PATCH v2 5/6] sched/fair: Select an energy-efficient CPU on task wake-up
@ https://lkml.org/lkml/2018/4/6/856