Re: [PATCH v2 10/12] sched/core: uclamp: use TG's clamps to restrict Task's clamps

[Suren Baghdasaryan]

Sorry for the delay. Overlooked this comment...

On Tue, Jul 24, 2018 at 8:49 AM, Patrick Bellasi <patrick.bellasi@xxxxxxx> wrote:

On 24-Jul 08:28, Suren Baghdasaryan wrote:
> Hi Patrick. Thanks for the explanation and links. No more questions
> from me on this one :)

No problems at all!

The important question is instead: does it makes sense for you too?

Well, it still feels unnatural to me due to the definition of the boost (at least this much CPU bandwidthÂbut higher should be fine).

Say I have a task which normally has specific boost and clamp requirements (say TG.UCLAMP_MIN=20,ÂTG.UCLAMP_MAX=80)Âwhich I want to temporarily boost using a syscall to UCLAMP_MIN=60 (let's sayÂa process should handle some request and temporarily needs more CPU bandwidth). With this interface we can clamp more than TG.UCLAMP_MAXÂvalue but we can't boost more than TG.UCLAMP_MIN. For this usecase I would have to set TG.UCLAMP_MIN=80, then use syscall to set SYSCALL.UCLAMP_MIN=20 to get effectiveÂUCLAMP_MIN=20 and then setÂSYSCALL.UCLAMP_MIN=60Âwhen I need that temporary boost.

To summarize, while this API does not stop me from achieving the desired result it requires some hoop-jumping :)

Â

I think the important bits are that we are all on the same page about
the end goals and features we like to have as well as the interface we use.
This last has to fits best our goals and features while still being
perfectly aligned with the frameworks we are integrating into... and
that's still under discussion with Tejun on PATCH 08/12.

Thanks again for your review!

Cheers Patrick

--
#include <best/regards.h>

Patrick Bellasi