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Date:	Thu, 23 Feb 2012 17:02:24 +0530
From:	Srivatsa Vaddagiri <>
To:	Ingo Molnar <>
Cc:	Mike Galbraith <>,
	Peter Zijlstra <>,
	Suresh Siddha <>,
	linux-kernel <>,
	Paul Turner <>
Subject: Re: sched: Avoid SMT siblings in select_idle_sibling() if possible

* Ingo Molnar <> [2012-02-23 12:26:50]:

> pro perf tip of the day: did you know that it's possible to run:
>   perf stat --repeat 10 --null perf bench sched pipe

Ah yes ..had forgotten that! What is the recommended # of iterations 
to run?

> and get meaningful, normalized stddev calculations for free:
>        5.486491487 seconds time elapsed                                          ( +-  5.50% )
> the percentage at the end shows the level of standard deviation.
> You can add "--sync" as well, which will cause perf stat to call 
> sync() - this gives extra stability of individual iterations and 
> makes sure all IO cost is accounted to the right run.

Ok ..thanks for the 'pro' tip!! Will use it in my subsequent runs!

- vatsa

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