[Xen-devel] RE: [PATCH] CPUIDLE: shorten hpet spin_lock holding time

["Wei, Gang" <gang.wei@xxxxxxxxx>]

On Thursday, 2010-4-22 4:21 PM, Keir Fraser wrote:
> On 20/04/2010 17:05, "Wei, Gang" <gang.wei@xxxxxxxxx> wrote:
> 
>> Resend.
>> 
>> CPUIDLE: shorten hpet spin_lock holding time
>> 
>> Try to reduce spin_lock overhead for deep C state entry/exit. This
>> will benefit systems with a lot of cpus which need the hpet
>> broadcast to wakeup from deep C state. 
>> 
>> Signed-off-by: Wei Gang <gang.wei@xxxxxxxxx>
> 
> I was going to ask: do you still get the decent power-saving win from
> this new version of the patch? You acquire/release the lock a lot more
> potentially in this version, since you do so inside the loop over
> cpumask in handle_hpet_broadcast().

Yes, I tested it and could still get the decent power-saving win from it. And 
it should not have racing issue after the mwait-wakeup re-implementation patch.

Jimmy
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