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From: Peter Zijlstra <peterz@infradead.org>
To: Vincent Guittot <vincent.guittot@linaro.org>
Cc: K Prateek Nayak <kprateek.nayak@amd.com>,
	mingo@redhat.com, juri.lelli@redhat.com,
	dietmar.eggemann@arm.com, rostedt@goodmis.org,
	bsegall@google.com, mgorman@suse.de, vschneid@redhat.com,
	linux-kernel@vger.kernel.org, qyousef@layalina.io
Subject: Re: [PATCH 6/6 v3] sched/eevdf: Speedup short slice task scheduling
Date: Fri, 26 Jun 2026 09:18:32 +0200	[thread overview]
Message-ID: <20260626071832.GH1181229@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <CAKfTPtDY0ELN799VaRzMiQOp_==L2O_Ww5X85fz7tp8CphpFGQ@mail.gmail.com>

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@amd.com> 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.

  reply	other threads:[~2026-06-26  7:18 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-06-24 15:12 [PATCH 0/6 v3] sched/eevdf: Improve scheduling latency of short slice task Vincent Guittot
2026-06-24 15:12 ` [PATCH 1/6 v3] sched/fair: Set next buddy for preempt short Vincent Guittot
2026-06-25  6:24   ` K Prateek Nayak
2026-06-25 12:40     ` Vincent Guittot
2026-06-25 12:43       ` Peter Zijlstra
2026-06-26  6:54       ` Peter Zijlstra
2026-06-26  7:02         ` Vincent Guittot
2026-06-26  8:08           ` Peter Zijlstra
2026-06-26  8:55             ` Vincent Guittot
2026-06-30  9:03   ` [tip: sched/core] " tip-bot2 for Vincent Guittot
2026-06-24 15:12 ` [PATCH 2/6 v3] sched/eevdf: Take into account current's lag when updating slice protection Vincent Guittot
2026-06-30  9:03   ` [tip: sched/core] " tip-bot2 for Vincent Guittot
2026-06-24 15:12 ` [PATCH 3/6 v3] sched/eevdf: Update slice protection even when resched is already set Vincent Guittot
2026-06-26  7:21   ` Peter Zijlstra
2026-06-26  7:46     ` Peter Zijlstra
2026-06-30  9:03       ` [tip: sched/core] sched/core: Fix inter-class wakeup_preempt() tip-bot2 for Peter Zijlstra
2026-06-30  9:03   ` [tip: sched/core] sched/eevdf: Update slice protection even when resched is already set tip-bot2 for Vincent Guittot
2026-06-24 15:12 ` [PATCH 4/6 v3] sched/eevdf: Cancel slice protection if short slice task is eligible Vincent Guittot
2026-06-25  6:00   ` K Prateek Nayak
2026-06-25 12:40     ` Vincent Guittot
2026-06-26  5:51       ` Shubhang Kaushik
2026-06-26  7:39         ` Vincent Guittot
2026-06-30  9:03   ` [tip: sched/core] " tip-bot2 for Vincent Guittot
2026-06-24 15:12 ` [PATCH 5/6 v3] sched/eevdf: Always update slice protection Vincent Guittot
2026-06-30  9:03   ` [tip: sched/core] " tip-bot2 for Vincent Guittot
2026-06-24 15:12 ` [PATCH 6/6 v3] sched/eevdf: Speedup short slice task scheduling Vincent Guittot
2026-06-25  7:37   ` K Prateek Nayak
2026-06-25  8:37     ` Peter Zijlstra
2026-06-25 10:09       ` Peter Zijlstra
2026-06-25 12:57         ` Vincent Guittot
2026-06-25 12:59           ` Vincent Guittot
2026-06-25 22:28             ` Peter Zijlstra
2026-06-26  3:57               ` K Prateek Nayak
2026-06-26  6:41                 ` Peter Zijlstra
2026-06-26  7:05                 ` Vincent Guittot
2026-06-26  7:18                   ` Peter Zijlstra [this message]
2026-06-26  7:54                     ` Peter Zijlstra
2026-06-26  8:55                       ` Vincent Guittot
2026-06-26 13:55                         ` Vincent Guittot
2026-06-29 14:25                           ` Vincent Guittot
2026-06-25 14:55       ` Vincent Guittot
2026-06-25 12:51     ` Vincent Guittot
2026-06-25  8:33   ` Peter Zijlstra
2026-06-30  9:03   ` [tip: sched/core] " tip-bot2 for Vincent Guittot

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