linux-kernel - Re: [PATCH] sched: Increase sched_tick

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Message-ID: <20251103215623.GA73531@pauld.westford.csb>
Date: Mon, 3 Nov 2025 16:56:23 -0500
From: Phil Auld <pauld@...hat.com>
To: peterz@...radead.org
Cc: bsegall@...gle.com, dietmar.eggemann@....com, juri.lelli@...hat.com,
	linux-kernel@...r.kernel.org, mgorman@...e.de, mingo@...hat.com,
	frederic@...nel.org, rostedt@...dmis.org, tanghui20@...wei.com,
	tglx@...utronix.de, vincent.guittot@...aro.org,
	wangtao554@...wei.com, zhangqiao22@...wei.com,
	Waiman Long <longman@...hat.com>
Subject: Re: [PATCH] sched: Increase sched_tick_remote timeout


Hi Peter,

On Tue, Sep 23, 2025 at 06:47:39AM -0400 Phil Auld wrote:
> Hi,
> 
> On Thu, Sep 11, 2025 at 12:13:00PM -0400 Phil Auld wrote:
> > Increase the sched_tick_remote WARN_ON timeout to remove false
> > positives due to temporarily busy HK cpus. The suggestion
> > was 30 seconds to catch really stuck remote tick processing
> > but not trigger it too easily.
> > 
> > Signed-off-by: Phil Auld <pauld@...hat.com>
> > Suggested-by: Frederic Weisbecker <frederic@...nel.org>
> > Cc: Peter Zijlstra <peterz@...radead.org>
> > Cc: Frederic Weisbecker <frederic@...nel.org>
> 
> Frederic ack'd this. Any other thoughts or opinions on this one
> character patch?

Can we have this timeout increase, please? 


Thanks,
Phil

> 
> Cheers,
> Phil
> 
> 
> 
> > ---
> >  kernel/sched/core.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> > index be00629f0ba4..ef90d358252d 100644
> > --- a/kernel/sched/core.c
> > +++ b/kernel/sched/core.c
> > @@ -5724,7 +5724,7 @@ static void sched_tick_remote(struct work_struct *work)
> >  				 * reasonable amount of time.
> >  				 */
> >  				u64 delta = rq_clock_task(rq) - curr->se.exec_start;
> > -				WARN_ON_ONCE(delta > (u64)NSEC_PER_SEC * 3);
> > +				WARN_ON_ONCE(delta > (u64)NSEC_PER_SEC * 30);
> >  			}
> >  			curr->sched_class->task_tick(rq, curr, 0);
> >  
> > -- 
> > 2.51.0
> > 
> 
> -- 
> 
> 

--