Re: sched: Avoid SMT siblings in select_idle_sibling() if possible

From: Peter Zijlstra
Date: Fri Nov 18 2011 - 10:12:29 EST


On Thu, 2011-11-17 at 11:08 -0800, Suresh Siddha wrote:
>
> From: Suresh Siddha <suresh.b.siddha@xxxxxxxxx>
> 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@xxxxxxxxx>
> Cc: Mike Galbraith <efault@xxxxxx>

Thanks Suresh!
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