Re: [RFC PATCH 1/1] sched/pelt: Introduce PELT multiplier

[Dietmar Eggemann]

On 29/08/2022 12:13, Vincent Guittot wrote:
> On Mon, 29 Aug 2022 at 12:03, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
>>
>> On Mon, Aug 29, 2022 at 10:08:13AM +0200, Peter Zijlstra wrote:
>>> On Mon, Aug 29, 2022 at 07:54:50AM +0200, Dietmar Eggemann wrote:
>>>> From: Vincent Donnefort <vincent.donnefort@xxxxxxx>

[...]

>>> Hurmph... I'd almost go write you something like
>>> static_call()/static_branch() but for immediates.
>>>
>>> That said; given there's only like 3 options, perhaps a few
>>> static_branch() instances work just fine ?
>>
>> Also, I'm not at all sure about exposing that as an official sysctl.
> 
> Me too, I would even make it a boot time parameter so we can remove

Isn't a sched feature even less official than a boot parameter?
But AFAIK at least some of the Android folks want to change this during
runtime and they don't have debugfs mounted.

> the new clock_task_mult clock and left shift clock_taslk or the delta
> before passing it to clock_pelt

We still need rq_clock_task_mult(rq), i.e. `rq->clock_task_mult` in
_update_idle_rq_clock_pelt() though.