Re: [PATCH 2/4] nohz: Synchronize sleep time stats with seqlock

[Arjan van de Ven]

On 8/20/2013 8:29 AM, Frederic Weisbecker wrote:

> > Of course, if we can get away with completely removing all of that
> > (which I think Arjan suggested was a real possibility) then that would
> > be ever so much better still :-)
>
> Would be lovely. But I don't know much about cpufreq, I hope somebody who's
> familiar with that code can handle this. Then once there are no more users
> of get_cpu_iowait_sleep_time() I can simply zap and clean the tick/time related
> code.

it's just doing the "idle = 100 - busy% - iowait%" calculation.
(with the later part only for Intel cpus iirc)

in a perfect world the scheduler would be doing that calculation in the first place ;-)

removing the later part will impact performance some on specific workloads,
but most Intel cpus that this applies to should not be using cpufreq anymore
anyway.


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