From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Vladimir Davydov <VDavydov@parallels.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>,
Ingo Molnar <mingo@elte.hu>, Len Brown <lenb@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] cpuidle: menu: use nr_running instead of cpuload for calculating perf mult
Date: Mon, 04 Jun 2012 19:17:59 +0200 [thread overview]
Message-ID: <1338830279.28282.117.camel@twins> (raw)
In-Reply-To: <33E662E8-48BF-49A7-A4A0-CB1A751AAEBC@parallels.com>
On Mon, 2012-06-04 at 21:08 +0400, Vladimir Davydov wrote:
> But this_cpu_load(), which is currently used by cpuidle, does not
> return the "load average". It returns the value of cpuload at some
> moment in the past (actually, the value is updated in
> update_cpu_load()). This value is usually used for load balancing.
>
> Moreover, this value does not reflect the real cpu load from the
> cpuidle pow, because it depends on tasks priority (nice) and, what is
> worse, with the introduction of cgroups it can be pretty arbitrary.
> For instance, each group of tasks is accounted just as a single task
> with standard priority "spreaded" among all cpus, no matter how many
> tasks are actually running in it.
Indeed.
next prev parent reply other threads:[~2012-06-04 17:18 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-04 10:24 Vladimir Davydov
2012-06-04 10:32 ` Peter Zijlstra
2012-06-04 10:50 ` Vladimir Davydov
2012-06-04 13:13 ` Arjan van de Ven
2012-06-04 13:45 ` Peter Zijlstra
2012-06-04 13:48 ` Arjan van de Ven
2012-06-04 15:08 ` Peter Zijlstra
2012-06-04 15:14 ` Arjan van de Ven
2012-06-04 15:26 ` Peter Zijlstra
2012-06-04 15:39 ` Arjan van de Ven
2012-06-04 16:33 ` Peter Zijlstra
2012-06-04 16:53 ` Arjan van de Ven
2012-06-04 17:08 ` Vladimir Davydov
2012-06-04 17:17 ` Peter Zijlstra [this message]
2012-06-04 17:16 ` Peter Zijlstra
2012-06-04 17:25 ` Arjan van de Ven
2012-06-04 20:31 ` Peter Zijlstra
2012-06-04 20:45 ` Arjan van de Ven
2012-06-04 21:14 ` Peter Zijlstra
2012-06-04 20:40 ` Peter Zijlstra
2012-06-05 3:48 ` Mike Galbraith
2012-06-04 13:15 ` Arjan van de Ven
2012-06-04 13:19 ` Vladimir Davydov
2012-11-27 19:02 ` Vladimir Davydov
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