Re: [PATCH] cpuidle: menu governor: reduce latency on exit

[Corrado Zoccolo <czoccolo@gmail.com>]

Hi Andrew,
the expected effect is to reduce processor wakeup latency from sleep (C-states).

We are speaking of few hundreds of cycles reduction out of a several
microseconds latency (determined by the hardware transition), so it is
difficult to measure.

Corrado

On Fri, Jul 24, 2009 at 12:05 AM, Andrew
Morton<akpm@linux-foundation.org> wrote:
> On Sun, 19 Jul 2009 16:59:46 +0200
> Corrado Zoccolo <czoccolo@gmail.com> wrote:
>
>> This patch moves the state residency accounting and statistics
>> computation off the hot exit path.
>> On exit, the need to recompute statistics is recorded, and new
>> statistics will be computed when menu_select is called again.
>>
>
> Was there any observed and/or measured effect as a result of this patch?
>
> If so, please send a description of that effect, thanks.
>
>



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dott. Corrado Zoccolo                          mailto:czoccolo@gmail.com
PhD - Department of Computer Science - University of Pisa, Italy
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