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From: K Prateek Nayak <kprateek.nayak@amd.com>
To: Peter Zijlstra <peterz@infradead.org>, John Stultz <jstultz@google.com>
Cc: <mingo@kernel.org>, <juri.lelli@redhat.com>,
	<vincent.guittot@linaro.org>, <dietmar.eggemann@arm.com>,
	<rostedt@goodmis.org>, <bsegall@google.com>, <mgorman@suse.de>,
	<vschneid@redhat.com>, <linux-kernel@vger.kernel.org>,
	<wangtao554@huawei.com>, <quzicheng@huawei.com>,
	<dsmythies@telus.net>, <shubhang@os.amperecomputing.com>,
	Suleiman Souhlal <suleiman@google.com>
Subject: Re: [PATCH v2 1/7] sched/fair: Fix zero_vruntime tracking
Date: Mon, 30 Mar 2026 20:07:06 +0530	[thread overview]
Message-ID: <73dab51a-650f-4c82-9e73-13236b2a26c2@amd.com> (raw)
In-Reply-To: <20260330101018.GN3738786@noisy.programming.kicks-ass.net>

Hello Peter,

On 3/30/2026 3:40 PM, Peter Zijlstra wrote:
> This means, that if the two tasks playing leapfrog can reach the
> critical speed to reach the overflow point inside one tick's worth of
> time, we're up a creek.
> 
> If this is indeed the case, then the below should cure things.

I have been running with this for four hours now and haven't seen
any splats or crashes on my setup. I could reliably trigger the
warning from __sum_w_vruntime_add() within an hour previously so
it is safe to say I was hitting exactly this.

Feel free to include:

Tested-by: K Prateek Nayak <kprateek.nayak@amd.com>

-- 
Thanks and Regards,
Prateek


  reply	other threads:[~2026-03-30 14:37 UTC|newest]

Thread overview: 56+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-02-19  7:58 [PATCH v2 0/7] sched: Various reweight_entity() fixes Peter Zijlstra
2026-02-19  7:58 ` [PATCH v2 1/7] sched/fair: Fix zero_vruntime tracking Peter Zijlstra
2026-02-23 10:56   ` Vincent Guittot
2026-02-23 13:09   ` Dietmar Eggemann
2026-02-23 14:15     ` Peter Zijlstra
2026-02-24  8:53       ` Dietmar Eggemann
2026-02-24  9:02         ` Peter Zijlstra
2026-03-28  5:44   ` John Stultz
2026-03-28 17:04     ` Steven Rostedt
2026-03-30 17:58       ` John Stultz
2026-03-30 18:27         ` Steven Rostedt
2026-03-30  9:43     ` Peter Zijlstra
2026-03-30 17:49       ` John Stultz
2026-03-30 10:10     ` Peter Zijlstra
2026-03-30 14:37       ` K Prateek Nayak [this message]
2026-03-30 14:40         ` Peter Zijlstra
2026-03-30 15:50           ` K Prateek Nayak
2026-03-30 19:11             ` Peter Zijlstra
2026-03-31  0:38               ` K Prateek Nayak
2026-03-31  4:58                 ` K Prateek Nayak
2026-03-31  7:08                 ` Peter Zijlstra
2026-03-31  7:14                   ` Peter Zijlstra
2026-03-31  8:49                     ` K Prateek Nayak
2026-03-31  9:29                       ` Peter Zijlstra
2026-03-31 12:20                         ` Peter Zijlstra
2026-03-31 16:14                           ` Peter Zijlstra
2026-03-31 17:02                             ` K Prateek Nayak
2026-03-31 22:40                             ` John Stultz
2026-03-30 19:40       ` John Stultz
2026-03-30 19:43         ` Peter Zijlstra
2026-03-30 21:45           ` John Stultz
2026-02-19  7:58 ` [PATCH v2 2/7] sched/fair: Only set slice protection at pick time Peter Zijlstra
2026-02-19  7:58 ` [PATCH v2 3/7] sched/eevdf: Update se->vprot in reweight_entity() Peter Zijlstra
2026-02-19  7:58 ` [PATCH v2 4/7] sched/fair: Fix lag clamp Peter Zijlstra
2026-02-23 10:23   ` Dietmar Eggemann
2026-02-23 10:57   ` Vincent Guittot
2026-02-19  7:58 ` [PATCH v2 5/7] sched/fair: Increase weight bits for avg_vruntime Peter Zijlstra
2026-02-23 10:56   ` Vincent Guittot
2026-02-23 11:51     ` Peter Zijlstra
2026-02-23 12:36       ` Peter Zijlstra
2026-02-23 13:06       ` Vincent Guittot
2026-03-30  7:55       ` K Prateek Nayak
2026-03-30  9:27         ` Peter Zijlstra
2026-04-02  5:28         ` K Prateek Nayak
2026-04-02 10:22           ` Peter Zijlstra
2026-04-02 10:56             ` K Prateek Nayak
2026-04-03  4:02               ` K Prateek Nayak
2026-04-07 12:00                 ` Peter Zijlstra
2026-04-07 13:42                   ` [tip: sched/core] sched/fair: Avoid overflow in enqueue_entity() tip-bot2 for K Prateek Nayak
2026-02-19  7:58 ` [PATCH v2 6/7] sched/fair: Revert 6d71a9c61604 ("sched/fair: Fix EEVDF entity placement bug causing scheduling lag") Peter Zijlstra
2026-02-23 10:57   ` Vincent Guittot
2026-03-24 10:01     ` William Montaz
2026-04-07 13:45       ` Peter Zijlstra
2026-04-15 21:10       ` [PATCH 6.18] " John Stultz
2026-02-19  7:58 ` [PATCH v2 7/7] sched/fair: Use full weight to __calc_delta() Peter Zijlstra
2026-02-23 10:57   ` Vincent Guittot

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