Re: [PATCH v2 00/13] sched/fair/schedutil: Better manage system response time

[John Stultz]

On Sun, May 3, 2026 at 7:00 PM Qais Yousef <qyousef@xxxxxxxxxxx> wrote:
>
> This is the long delayed follow up to the series sent back in August 2024 [1].
> Life got in the way to some extent (I had a baby, and now my time that I used
> to do upstream work late at night was stolen :). Apologies for those who
> replied and I didn't get a chance to respond back.
>
...
> Open questions:
>
> * The details of the QoS interface is the biggest one.
> * Would debugfs be better for setting the default rampup multiplier instead of sysctl?
> * Patch 13 makes updating load_avg unconditional not on period boundaries.
>
> Patches 1-3 are prepatory patches renaming a function and introducing new ones.
>
> Patches 4-5 handle the magic margin problem but making them dynamic based on
> actual hardware limitations.
>
> Patches 6-7 fix the black hole problem and teaches the scheduler how to handle
> bursty and periodic tasks via extending util_est.
>
> Patches 8-9 is where I expect most of the discussion on as I introduce a new
> sched_qos interface to support the new rampup_multiplier to help manage DVFS.
>
> Patches 10-11 introduces a couple of necessary optimizations to counter the
> power impact of increased responsiveness by disabling some features that we now
> know how to handle better.
>
> Patches 12-13 fix a couple of issues causing util_est and util_avg value to
> swing for a periodic task. Patch 12 must go via stable.

Just a minor nit, If 12/13 are fixes, should they not be at the front
of the series (or possibly sent separately) so they can potentially
move forward while the bigger changes in this series are discussed?

thanks
-john