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

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Message-ID: <20250923104739.GA514793@pauld.westford.csb>
Date: Tue, 23 Sep 2025 06:47:39 -0400
From: Phil Auld <pauld@...hat.com>
To: frederic@...nel.org
Cc: bsegall@...gle.com, dietmar.eggemann@....com, juri.lelli@...hat.com,
	linux-kernel@...r.kernel.org, mgorman@...e.de, mingo@...hat.com,
	peterz@...radead.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,

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?

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
> 

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