linux-kernel - Re: sched: Avoid SMT siblings in select_idle

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Message-ID: <1321629141.2197.4.camel@twins>
Date:	Fri, 18 Nov 2011 16:12:21 +0100
From:	Peter Zijlstra <peterz@...radead.org>
To:	Suresh Siddha <suresh.b.siddha@...el.com>
Cc:	Mike Galbraith <efault@....de>,
	linux-kernel <linux-kernel@...r.kernel.org>,
	Ingo Molnar <mingo@...e.hu>, Paul Turner <pjt@...gle.com>
Subject: Re: sched: Avoid SMT siblings in select_idle_sibling() if possible

On Thu, 2011-11-17 at 11:08 -0800, Suresh Siddha wrote:
> 
> From: Suresh Siddha <suresh.b.siddha@...el.com>
> Subject: sched: cleanup domain traversal in select_idle_sibling
> 
> Instead of going through the scheduler domain hierarchy multiple times
> (for giving priority to an idle core over an idle SMT sibling in a busy
> core), start with the highest scheduler domain with the SD_SHARE_PKG_RESOURCES
> flag and traverse the domain hierarchy down till we find an idle group.
> 
> This cleanup also addresses an issue reported by Mike where the recent
> changes returned the busy thread even in the presence of an idle SMT
> sibling in single socket platforms.
> 
> Signed-off-by: Suresh Siddha <suresh.b.siddha@...el.com>
> Cc: Mike Galbraith <efault@....de> 

Thanks Suresh!
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