From: john stultz <johnstul@us.ibm.com>
To: Arjan van de Ven <arjan@infradead.org>
Cc: linux-kernel@vger.kernel.org, tglx@linutronix.de,
linux-arch@vger.kernel.org
Subject: Re: [patch] Remove the per cpu tick skew
Date: Wed, 28 Jul 2010 16:50:40 -0700 [thread overview]
Message-ID: <AANLkTim3h4VNqF97d++k4_4g-4hnw57YXJSQgSEP4S7m@mail.gmail.com> (raw)
In-Reply-To: <AANLkTikZ_RHHv9cudUh8pp9H8MtKO8Rsr+eboupv49xD@mail.gmail.com>
On Wed, Jul 28, 2010 at 1:26 PM, john stultz <johnstul@us.ibm.com> wrote:
> On Tue, Jul 27, 2010 at 9:02 PM, Arjan van de Ven <arjan@infradead.org> 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.
thanks
-john
next prev parent reply other threads:[~2010-07-28 23:50 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-07-28 4:02 [patch] Remove the per cpu tick skew Arjan van de Ven
2010-07-28 20:26 ` john stultz
2010-07-28 23:50 ` john stultz [this message]
2010-07-30 7:27 ` Nick Piggin
2010-07-30 7:27 ` Nick Piggin
2010-07-30 13:57 ` Arjan van de Ven
2010-07-30 13:57 ` Arjan van de Ven
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