Re: [PATCH] cpuidle: powernv/pseries: Decrease the snooze residency

From: Preeti U Murthy
Date: Sat May 30 2015 - 04:00:45 EST


On 05/30/2015 11:31 AM, Vaidyanathan Srinivasan wrote:
> * Preeti U Murthy <preeti@xxxxxxxxxxxxxxxxxx> [2015-05-29 19:17:17]:
>
> [snip]
>
>>> + if (max_idle_state > 1) {
>>> + snooze_timeout_en = true;
>>> + snooze_timeout = cpuidle_state_table[1].target_residency *
>>> + tb_ticks_per_usec;
>>> + }
>>
>> Any idea why we don't have snooze defined on the shared lpar configuration ?
>
> In shared lpar case, spinning in guest context may potentially take
> away cycles from other lpars waiting to run on the same physical cpu.
>
> So the policy in shared lpar case is to let PowerVM hypervisor know
> immediately that the guest cpu is idle which will allow the hypervisor
> to use the cycles for other tasks/lpars.
>

Oh Ok! Thanks for the clarification !

Regards
Preeti U Murthy
> --Vaidy
>

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