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From: Madadi Vineeth Reddy <vineethr@linux.ibm.com>
To: kprateek.nayak@amd.com
Cc: bsegall@google.com, dietmar.eggemann@arm.com,
	gautham.shenoy@amd.com, juri.lelli@redhat.com,
	linux-kernel@vger.kernel.org, mgorman@suse.de, mingo@redhat.com,
	peterz@infradead.org, rostedt@goodmis.org,
	swapnil.sapkal@amd.com, vincent.guittot@linaro.org,
	vschneid@redhat.com, vineethr@linux.ibm.com
Subject: Re: [PATCH] sched/fair: Fix inaccurate h_nr_runnable accounting with delayed dequeue
Date: Mon, 20 Jan 2025 10:36:39 +0530	[thread overview]
Message-ID: <20250120050639.48966-1-vineethr@linux.ibm.com> (raw)
In-Reply-To: <20250117105852.23908-1-kprateek.nayak@amd.com>

Hi Prateek,

>A SCHED_WARN_ON() to inspect h_nr_runnable post its update in
>dequeue_entities() like below:
>
>    cfs_rq->h_nr_runnable -= h_nr_runnable;
>    SCHED_WARN_ON(((int) cfs_rq->h_nr_runnable) < 0);
>
>is consistently tripped when running wakeup intensive workloads like
>hackbench in a cgroup.

I observed that the WARN_ON is triggered during the boot process without
the patch, and the patch resolves the issue.

However, I was unable to trigger the WARN_ON by running hackbench in a
cgroup without the patch. Could you please share the specific test
scenario or configuration you used to reproduce it?

For the boot process scenario:
Tested-by: Madadi Vineeth Reddy <vineethr@linux.ibm.com>

Thanks,
Madadi Vineeth Reddy

  parent reply	other threads:[~2025-01-20  5:07 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-01-17 10:58 [PATCH] sched/fair: Fix inaccurate h_nr_runnable accounting with delayed dequeue K Prateek Nayak
2025-01-17 13:25 ` Vincent Guittot
2025-01-17 15:59   ` K Prateek Nayak
2025-01-18  8:30     ` Vincent Guittot
2025-01-21  8:09       ` K Prateek Nayak
2025-01-21  9:53         ` Vincent Guittot
2025-01-20  5:06 ` Madadi Vineeth Reddy [this message]
2025-01-20  8:44   ` Madadi Vineeth Reddy
2025-01-20  9:14     ` K Prateek Nayak
2025-01-20  9:12   ` K Prateek Nayak
2025-01-21 12:21 ` [tip: sched/urgent] " tip-bot2 for K Prateek Nayak

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