Re: [PATCH] sched/rt: Don't reschedule a throttled task even if it's higher priority

From: Joel Fernandes
Date: Tue Nov 30 2021 - 18:37:12 EST


On Tue, Nov 30, 2021 at 11:30 AM Doug Anderson <dianders@xxxxxxxxxxxx> wrote:
> I know this isn't crazy urgent and I'm happy to sit and twiddle my
> thumbs a bit longer if everyone is still sleepy from tryptophan, but
> I'm curious if anyone had a chance to look at this. Can anyone confirm
> that my script reproduces for them on something other than my system?

Maybe +Qais Yousef can also chime in. Just to add, I think Doug's
issue is that under RT group scheduling, he expects *other* well
behaved RT tasks to not be throttled while the tasks that are
misbehaving to be *gracefully* throttled. Gracefully being- it is
probably WAI that they are exceeding their runtime and so *should
naturally* be bandwidth-limited similar to deadline. I am not sure if
the design of RT throttling considers throttling as an anomaly or
something that's expected to happen. If it is expected to happen, then
I see Doug's point that the mechanism shouldn't affect other RT tasks.

> Does my patch seem sane?

To be honest, I don't understand that bit enough :(

-Joel