Re: [PATCH] cpuidle: menu: use nr_running instead of cpuload forcalculating perf mult

From: Peter Zijlstra
Date: Mon Jun 04 2012 - 13:18:07 EST


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.
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