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Message-ID: <1343295457.6863.43.camel@marge.simpson.net>
Subject: Re: [PATCH 1/2] sched: recover SD_WAKE_AFFINE in
 select_task_rq_fair and code clean up
From: Mike Galbraith <efault@gmx.de>
To: Alex Shi <alex.shi@intel.com>
Cc: mingo@redhat.com, peterz@infradead.org, linux-kernel@vger.kernel.org,
        suresh.b.siddha@intel.com
Date: Thu, 26 Jul 2012 11:37:37 +0200
In-Reply-To: <1343280446-24019-1-git-send-email-alex.shi@intel.com>
References: <1343280446-24019-1-git-send-email-alex.shi@intel.com>
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On Thu, 2012-07-26 at 13:27 +0800, Alex Shi wrote:

> 	if (affine_sd) {
> -		if (cpu == prev_cpu || wake_affine(affine_sd, p, sync))
> +		if (wake_affine(affine_sd, p, sync))
>  			prev_cpu = cpu;
>  
>  		new_cpu = select_idle_sibling(p, prev_cpu);

Hm, if cpu == prev_cpu, asking wake_affine() if it's ok to put wakee
back where it came from is wasted cycles.. that's where the task is
headed regardless of reply.

-Mike