Re: [discussion]sched: a rough proposal to enable power saving in scheduler

[Vincent Guittot]

On 16 August 2012 07:03, Alex Shi <alex.shi@xxxxxxxxx> wrote:
> On 08/16/2012 12:19 AM, Matthew Garrett wrote:
>
>> On Mon, Aug 13, 2012 at 08:21:00PM +0800, Alex Shi wrote:
>>
>>> power aware scheduling), this proposal will adopt the
>>> sched_balance_policy concept and use 2 kind of policy: performance, power.
>>
>> Are there workloads in which "power" might provide more performance than
>> "performance"? If so, don't use these terms.
>>
>
>
> Power scheme should no chance has better performance in design.

A side effect of packing small tasks on one core is that you always
use the core with the lowest C-state which will minimize the wake up
latency so you can sometime get better results than performance mode
which will try to use a other core in another cluster which will take
more time to wake up that waiting for the end of the current task.

Vincent
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