From: Arjan van de Ven <arjan@infradead.org>
To: Nick Piggin <npiggin@suse.de>
Cc: linux-kernel@vger.kernel.org, tglx@linutronix.de,
linux-arch@vger.kernel.org
Subject: Re: [patch] Remove the per cpu tick skew
Date: Fri, 30 Jul 2010 06:57:14 -0700 [thread overview]
Message-ID: <20100730065714.3179df46@infradead.org> (raw)
In-Reply-To: <20100730072704.GA9960@amd>
On Fri, 30 Jul 2010 17:27:04 +1000
Nick Piggin <npiggin@suse.de> wrote:
> > 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.
>
> Question, how much of a win is it? What does it do that tickless
> idle does not, can you explain?
tickless idle works great if you're really almost idle
if there's "some work but not fully busy" this still matters
this is not about 'a few milliwatts', but on a server in our labs
(sorry, no hardware details in public) this effect is in the "several
dozen Watts" range.
--
Arjan van de Ven Intel Open Source Technology Centre
For development, discussion and tips for power savings,
visit http://www.lesswatts.org
next prev parent reply other threads:[~2010-07-30 13:57 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
2010-07-30 7:27 ` Nick Piggin
2010-07-30 7:27 ` Nick Piggin
2010-07-30 13:57 ` Arjan van de Ven [this message]
2010-07-30 13:57 ` Arjan van de Ven
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