From: Vladimir Davydov <VDavydov@parallels.com>
To: Arjan van de Ven <arjan@linux.intel.com>
Cc: Ingo Molnar <mingo@elte.hu>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
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, 4 Jun 2012 17:19:08 +0400 [thread overview]
Message-ID: <9511B40F-7F71-4A99-87B8-4CD88C83FE4E@parallels.com> (raw)
In-Reply-To: <4FCCB4DD.4060407@linux.intel.com>
On Jun 4, 2012, at 5:15 PM, "Arjan van de Ven" <arjan@linux.intel.com> wrote:
> On 6/4/2012 3:24 AM, Vladimir Davydov wrote:
>> rq->cpuload strongly depends on cgroup hierarchy. For example, if hundreds of
>> tasks are running inside cpu:/test cgroup, the sum of cpuload over all cpus
>> won't exceed 1024 (by default). That makes the cpuidle menu governor take wrong
>> decisions, which can negatively affect overall performance.
>
> nr_running is the wrong answer... it is instantaneous, not longer term.
> cpuidle wants a longer term, per cpu, notion of "busy", to use as proxy
> for performance sensitivity.
>
>
I use not the instantaneous nr_running, but nr_running last seen in update_cpu_load() where cpuload[0], which is currently used by cpuidle, is updated.
next prev parent reply other threads:[~2012-06-04 13:19 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
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 [this message]
2012-11-27 19:02 ` Vladimir Davydov
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