Re: [PATCH 2/4] sched: cpufreq: Keep track of cpufreq utilization update flags

From: Viresh Kumar
Date: Mon Dec 18 2017 - 00:00:06 EST

On 17-12-17, 01:19, Rafael J. Wysocki wrote:
> We can do that in principle, but why should it return early? Maybe it's
> a good time to update things, incidentally?
> I actually don't like the SCHED_CPUFRREQ_CLEAR flag *concept* as it is very
> much specific to schedutil and blatantly ignores everybody else.
> Alternatively, you could add two flags for clearing SCHED_CPUFREQ_RT and
> SCHED_CPUFREQ_DL that could just be ingored entirely by intel_pstate.
> So, why don't you make SCHED_CPUFREQ_RT and SCHED_CPUFREQ_DL "sticky" until,
> say, SCHED_CPUFREQ_NO_RT and SCHED_CPUFREQ_NO_DL are passed, respectively?

I didn't like adding scheduling class specific flags, and wanted the code to
treat all of them in the same way. And then the governors can make a policy over
that, on what to ignore and what not to. For example with the current patchset,
the governors can know when nothing else is queued on a CPU and CPU is going to
get into idle loop. They can choose to (or not to) do something in that case.

I just thought that writing consistent (i.e. no special code) code across all
classes would be better.