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

[Keir Fraser <keir.fraser@xxxxxxxxxxxxx>]

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().

 -- Keir




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