Re: [PATCH 6/6 v3] sched/eevdf: Speedup short slice task scheduling

[Peter Zijlstra]

On Fri, Jun 26, 2026 at 09:05:29AM +0200, Vincent Guittot wrote:
> On Fri, 26 Jun 2026 at 05:57, K Prateek Nayak <kprateek.nayak@xxxxxxx> wrote:
> >
> > Hello Peter,
> >
> > On 6/26/2026 3:58 AM, Peter Zijlstra wrote:
> > > +static u64 ineligible_vruntime(struct cfs_rq *cfs_rq)
> > > +{
> > > +     struct sched_entity *curr = cfs_rq->curr;
> > > +     long weight = cfs_rq->sum_weight;
> > > +     s64 delta = 0;
> > > +
> > > +     if (curr && !curr->on_rq)
> > > +             curr = NULL;
> > > +
> > > +     /*
> > > +      * This is called from set_next_task_fair(.first=true) /
> > > +      * set_protect_slice() so curr had better be set and on_rq.
> > > +      */
> > > +     WARN_ON_ONCE(!curr);
> >
> > set_protect_slice() is indeed called from set_next_entity(.first=true)
> > but it is done after __dequeue_entity() and before "cfs_rq->curr" is
> > set (both sched/flat and sched/core have the same pattern).
> 
> Yes, I confirm that set_protect_slice() is called before setting curr
> in tip/sched/core but I think that Peter added flat hierarchy patches
> in his tree

Indeed I did; I was planning to stick them in this cycle, so I figure I
should be doing these patches on top.