Re: [RFC PATCH v3 0/6] sched/cpufreq: Make schedutil energy aware

From: Quentin Perret
Date: Thu Oct 17 2019 - 07:11:24 EST


On Thursday 17 Oct 2019 at 11:50:15 (+0200), Peter Zijlstra wrote:
> Now, the thing is, we use map_util_freq() in more places, and should we
> not reflect this increase in C for all of them? That is, why is this
> patch changing get_next_freq() and not map_util_freq().
>
> I don't think that question is answered in the Changelogs.
>
> Exactly because it does change the energy consumption (it must) should
> that not also be reflected in the EAS logic?

Right that shouldn't hurt and keep things consistent. That probably
won't have a huge impact in practice (the boost should be != 0 only when
the util signals haven't converged IIUC, which is a case where the EAS
calculation is already 'wrong' anyway), but that still feels like the
right thing to do.

> I'm still thinking about the exact means you're using to raise C; that
> is, the 'util - util_est' as cost_margin. It hurts my brain still.

+1 ...

Thanks,
Quentin