Re: [PATCH] cpufreq: schedutil: add up/down frequency transition rate limits

From: Viresh Kumar
Date: Mon Nov 21 2016 - 05:48:08 EST

On 21-11-16, 11:19, Peter Zijlstra wrote:
> Urgh...
> So no tunables and rate limits here at all please.
> During LPC we discussed the rampup and decay issues and decided that we
> should very much first address them by playing with the PELT stuff.
> Morton was going to play with capping the decay on the util signal. This
> should greatly improve the ramp-up scenario and cure some other wobbles.
> The decay can be set by changing the over-all pelt decay, if so desired.
> Also, there was the idea of; once the above ideas have all been
> explored; tying the freq ram rate to the power curve.
> So NAK on everything tunable here.

Okay, as I told you on IRC, we already have a tunable: rate_limit_us for the
schedutil governor which defines the minimum time before which the governor
wouldn't try to update the frequency again. Perhaps 10-20 ms is the ideal value
for that everyone is using.

So eventually that should also die and we should get inputs from PELT stuff ?