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SubjectRe: [RFD PATCH 4/5] sched/cpufreq_schedutil: always consider all CPUs when deciding next freq
Hi,

On 30/03/17 00:41, Rafael J. Wysocki wrote:
> On Friday, March 24, 2017 02:08:59 PM Juri Lelli wrote:
> > No assumption can be made upon the rate at which frequency updates get
> > triggered, as there are scheduling policies (like SCHED_DEADLINE) which
> > don't trigger them so frequently.
> >
> > Remove such assumption from the code.
>
> But the util/max values for idle CPUs may be stale, no?
>

Right, that might be a problem. A proper solution I think would be to
remotely update such values for idle CPUs, and I believe Vincent is
working on a patch for that.

As mid-term workarounds, changing a bit the current one, come to my
mind:

- consider TICK_NSEC (continue) only when SCHED_CPUFREQ_DL is not set
- remove CFS contribution (without triggering a freq update) when a CPU
enters IDLE; this might not work well, though, as we probably want
to keep in blocked util contribution for a bit

What you think is the way to go?

Thanks,

- Juri

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