Re: [patch] Remove the per cpu tick skew

From: john stultz
Date: Wed Jul 28 2010 - 19:50:53 EST

On Wed, Jul 28, 2010 at 1:26 PM, john stultz <johnstul@xxxxxxxxxx> wrote:
> On Tue, Jul 27, 2010 at 9:02 PM, Arjan van de Ven <arjan@xxxxxxxxxxxxx> wrote:
>> Historically, Linux has tried to make the regular timer tick on the various
>> CPUs not happen at the same time, to avoid contention on xtime_lock.
>> Nowadays, with the tickless kernel, this contention no longer happens
>> since time keeping and updating are done differently. In addition,
>> this skew is actually hurting power consumption in a measurable
>> way on many-core systems.
> I'll give it a spin against -rt and see if we show any latency jumps.

In my testing on a 8way box, I didn't see any concerning latencies
with this patch running cyclictest or a FIFO99 gtod loop.

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