Re: [PATCH v4 2/3] sched/fair: Take thermal pressure into account while estimating energy

From: Lukasz Luba
Date: Wed Jun 16 2021 - 16:22:53 EST




On 6/16/21 8:25 PM, Vincent Guittot wrote:
On Wed, 16 Jun 2021 at 19:24, Dietmar Eggemann <dietmar.eggemann@xxxxxxx> wrote:

On 15/06/2021 18:09, Lukasz Luba wrote:

On 6/15/21 4:31 PM, Dietmar Eggemann wrote:
On 14/06/2021 21:11, Lukasz Luba wrote:

[...]

It's important to highlight that this will only fix this issue between
schedutil and EAS when it's due to `thermal pressure` (today only via
CPU cooling). There are other places which could restrict policy->max
via freq_qos_update_request() and EAS will be unaware of it.

True, but for this I have some other plans.

As long as people are aware of the fact that this was developed to be
beneficial for `EAS - IPA` integration, I'm fine with this.

I don't think it's only for EAS - IPA. Thermal_pressure can be used by
HW throttling like here:
https://lkml.org/lkml/2021/6/8/1791

EAS is involved but not IPA

Thank you Vincent for pointing to Thara's patches. Indeed, this is a
good example. We will have to provide similar for our SCMI perf
notifications - these are the plans that I've mentioned. In both
new examples, the IPA (or other governors) won't be even involved.