linux-kernel - Re: [PATCH v3] sched: Micro optimization in pick_next_task() and in check_preempt

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Date:   Thu, 19 Dec 2019 16:04:22 -0500
From:   Steven Rostedt <rostedt@...dmis.org>
To:     Kirill Tkhai <ktkhai@...tuozzo.com>
Cc:     "mingo@...hat.com" <mingo@...hat.com>,
        "peterz@...radead.org" <peterz@...radead.org>,
        LKML <linux-kernel@...r.kernel.org>,
        "juri.lelli@...hat.com" <juri.lelli@...hat.com>,
        "vincent.guittot@...aro.org" <vincent.guittot@...aro.org>,
        "dietmar.eggemann@....com" <dietmar.eggemann@....com>,
        "bsegall@...gle.com" <bsegall@...gle.com>,
        Mel Gorman <mgorman@...e.de>
Subject: Re: [PATCH v3] sched: Micro optimization in pick_next_task() and in
 check_preempt_curr()

On Thu, 19 Dec 2019 20:12:15 +0000
Kirill Tkhai <ktkhai@...tuozzo.com> wrote:

> This introduces an optimization based on xxx_sched_class addresses
> in two hot scheduler functions: pick_next_task() and check_preempt_curr().
> 
> It is possible to compare pointers to sched classes to check, which
> of them has a higher priority, instead of current iterations using
> for_each_class().
> 
> One more result of the patch is that size of object file becomes a little
> less (excluding added BUG_ON(), which goes in __init section):
> 
> $size kernel/sched/core.o
>          text     data      bss	    dec	    hex	filename
> before:  66446    18957	    676	  86079	  1503f	kernel/sched/core.o
> after:   66398    18957	    676	  86031	  1500f	kernel/sched/core.o
> 
> Signed-off-by: Kirill Tkhai <ktkhai@...tuozzo.com>

Care to resend, not as a mime image?

-- Steve


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