Re: [PATCH 10/24] sched/uclamg: Handle delayed dequeue

Mike Galbraith
2024-09-11T09:11:41Z

On Wed, 2024-09-11 at 10:45 +0200, Peter Zijlstra wrote:
> On Wed, Sep 11, 2024 at 09:35:16AM +0100, Luis Machado wrote:
> > >
> > > I'm assuming that removing the usage sites restores function?
> >
> > It does restore function if we remove the usage.
> >
> > From an initial look:
> >
> > cat /sys/kernel/debug/sched/debug | grep -i delay
> >   .h_nr_delayed                  : -4
> >   .h_nr_delayed                  : -6
> >   .h_nr_delayed                  : -1
> >   .h_nr_delayed                  : -6
> >   .h_nr_delayed                  : -1
> >   .h_nr_delayed                  : -1
> >   .h_nr_delayed                  : -5
> >   .h_nr_delayed                  : -6
> >
> > So probably an unexpected decrement or lack of an increment somewhere.
>
> Yeah, that's buggered. Ok, I'll go rebase sched/core and take this patch
> out. I'll see if I can reproduce that.

Hm, would be interesting to know how the heck he's triggering that.

My x86_64 box refuses to produce any such artifacts with anything I've
tossed at it, including full LTP with enterprise RT and !RT configs,
both in master and my local SLE15-SP7 branch. Hohum.

-Mike