Re: [patch 2/2] sched: fix select_idle_sibling() logic inselect_task_rq_fair()

From: Mike Galbraith
Date: Sat Mar 06 2010 - 03:37:16 EST

On Fri, 2010-03-05 at 10:39 -0800, Suresh Siddha wrote:
> plain text document attachment (fix_lat_ctx.patch)
> Performance improvements with this patch:
> "lat_ctx -s 0 2" ~22usec (before-this-patch) ~5usec (after-this-patch)

BTW, is your cpu governor kicking into high gear? That unpatched number
looks like a throttled down cpu to me. I know on my box, when there are
micro idles, sometimes cores do not throttle up, making for some fairly
crappy numbers. Q6600 doesn't throttle down far enough to make such a
_huge_ difference though.


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