Re: [PATCH 6/6] cpufreq: schedutil: New governor based on scheduler utilization data
From: Peter Zijlstra
Date: Thu Mar 10 2016 - 05:30:22 EST
On Thu, Mar 10, 2016 at 05:23:54PM +0700, Vincent Guittot wrote:
> > No, since its a compile time thing, we can simply do:
> > #ifdef arch_scale_freq_capacity
> > next_freq = (1 + 1/n) * max_freq * (util / max)
> > #else
> > next_freq = (1 + 1/n) * current_freq * (util_raw / max)
> > #endif
> selecting formula at compilation is clearly better. I wrongly thought that
> it can't be accepted as a solution.
Well, its bound to get more 'interesting' since I forse implementations
not always actually doing the invariant thing.
Take for example the thing I send:
it both shows why you cannot talk about current_freq but also that the
above needs a little more help (for the !X86_FEATURE_APERFMPERF case).
But the !arch_scale_freq_capacity case should indeed be that simple.