Re: [RFCv5 PATCH 40/46] sched/cpufreq_sched: compute freq_new based on capacity_orig_of()
From: Michael Turquette
Date: Sun Aug 16 2015 - 00:04:19 EST
Quoting Peter Zijlstra (2015-08-15 05:46:38)
> On Tue, Jul 07, 2015 at 07:24:23PM +0100, Morten Rasmussen wrote:
> > diff --git a/kernel/sched/cpufreq_sched.c b/kernel/sched/cpufreq_sched.c
> > index 2968f3a..7071528 100644
> > --- a/kernel/sched/cpufreq_sched.c
> > +++ b/kernel/sched/cpufreq_sched.c
> > @@ -184,7 +184,7 @@ void cpufreq_sched_set_cap(int cpu, unsigned long capacity)
> > goto out;
> >
> > /* Convert the new maximum capacity request into a cpu frequency */
> > - freq_new = capacity * policy->max >> SCHED_CAPACITY_SHIFT;
> > + freq_new = (capacity * policy->max) / capacity_orig_of(cpu);
> >
> > /* No change in frequency? Bail and return current capacity. */
> > if (freq_new == policy->cur)
>
> Can't we avoid exporting that lot by simply passing in the right values
> to begin with?
By "right value" do you mean, "pass the frequency from cfs"?
If that is what you mean, then the answer is "yes". But it also means
that cfs will need access to either:
1) the cpu frequncy-domain topology described in struct cpufreq.cpus
OR
2) duplicate that frequency-domain knowledge, perhaps in sched_domain
If that isn't what you mean by "right value" then let me know.
Regards,
Mike
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