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Re: [RESEND PATCH v2 1/2] sched/rt: add utilization tracking

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On Fri, Aug 04, 2017 at 03:40:21PM +0200, Vincent Guittot wrote:

> There were several comments on v1:
> - As raised by Peter for v1, if IRQ time is taken into account in
>   rt_avg, it will not be accounted in rq->clock_task. This means that cfs
>   utilization is not affected by some extra contributions or decays
>   because of IRQ.  

Right.

> - Regading the sync of rt and cfs utilization, both cfs and rt use the same
>   rq->clock_task. Then, we have the same issue than cfs regarding blocked value.
>   The utilization of idle cfs/rt rqs are not updated regularly but only when a
>   load_balance is triggered (more precisely a call to update_blocked_average).
>   I'd like to fix this issue for both cfs and rt with a separate patch that
>   will ensure that utilization (and load) are updated regularly even for
>   idle CPUs

Yeah, that needs help.

> - One last open question is the location of rt utilization function in fair.c
>   file. PELT related funtions should probably move in a dedicated pelt.c file.
>   This would also help to address one comment about having a place to update
>   metrics of NOHZ idle CPUs. Thought ?

Probably, but I have a bunch of patches lined up changing that code, so
lets not do that now.

In any case, would something like the attached patches make sense? It
completely replaces rt_avg with separate IRQ,RT and DL tracking.

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[RESEND PATCH v2 0/2] sched/rt: track rt rq utilization Vincent Guittot <vincent.guittot@linaro.org> - 2017-08-04 15:50 +0200
  [RESEND PATCH v2 2/2] cpufreq/schedutil: add rt utilization tracking Vincent Guittot <vincent.guittot@linaro.org> - 2017-08-04 15:50 +0200
  [RESEND PATCH v2 1/2] sched/rt: add utilization tracking Vincent Guittot <vincent.guittot@linaro.org> - 2017-08-04 15:50 +0200
    Re: [RESEND PATCH v2 1/2] sched/rt: add utilization tracking Peter Zijlstra <peterz@infradead.org> - 2017-08-07 18:50 +0200
      Re: [RESEND PATCH v2 1/2] sched/rt: add utilization tracking Vincent Guittot <vincent.guittot@linaro.org> - 2017-08-08 16:00 +0200
        Re: [RESEND PATCH v2 1/2] sched/rt: add utilization tracking Peter Zijlstra <peterz@infradead.org> - 2017-08-08 16:10 +0200

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