Re: [RFC PATCH 0/7] sched: cpufreq: Remove magic margins

Lukasz Luba
2023-09-07T17:33:24Z

On 9/7/23 14:26, Peter Zijlstra wrote:
> On Wed, Sep 06, 2023 at 10:18:50PM +0100, Qais Yousef wrote:
>
>> This is probably controversial statement. But I am not in favour of util_est.
>> I need to collect the data, but I think we're better with 16ms PELT HALFLIFE as
>> default instead. But I will need to do a separate investigation on that.
>
> I think util_est makes perfect sense, where PELT has to fundamentally
> decay non-running / non-runnable tasks in order to provide a temporal
> average, DVFS might be best served with a termporal max filter.
>
>

Since we are here...
Would you allow to have a configuration for
the util_est shifter: UTIL_EST_WEIGHT_SHIFT ?

I've found other values than '2' better in some scenarios. That helps
to prevent a big task to 'down' migrate from a Big CPU (1024) to some
Mid CPU (~500-700 capacity) or even Little (~120-300).