[Devel] Re: [PATCH v3 4/6] add a new scheduler hook for context switch

Glauber Costa glommer at parallels.com
Wed May 30 05:08:24 PDT 2012


On 05/30/2012 03:40 PM, Peter Zijlstra wrote:
> On Wed, 2012-05-30 at 13:20 +0200, Peter Zijlstra wrote:
>>
>> $ perf stat -e cycles --repeat 100 perf bench sched messaging -p -g 100
>>
>>      48,826,146,710 cycles  #    2.470 GHz  ( +-  0.17% )
>>         2.149005270 seconds time elapsed    ( +-  0.12% )
>
> A repeat count of 250 dropped it down to:
>
>          2.144582157 seconds time elapsed    ( +-  0.08% )
>
> Also, if you're poking at the context switch path, something like:
>
> $ taskset 1 perf stat -e cycles --repeat 10 perf bench sched pipe -l 100000
>
> gives a good number and is usually more stable than hackbench.
thanks for the pointers




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