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From: Peter Zijlstra <peterz@infradead.org>
To: Saravana Kannan <saravanak@google.com>
Cc: Ingo Molnar <mingo@redhat.com>,
	Juri Lelli <juri.lelli@redhat.com>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Dietmar Eggemann <dietmar.eggemann@arm.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Benjamin Segall <bsegall@google.com>,
	Mel Gorman <mgorman@suse.de>,
	Valentin Schneider <vschneid@redhat.com>,
	LKML <linux-kernel@vger.kernel.org>,
	wuyun.abel@bytedance.com, youssefesmat@chromium.org,
	Thomas Gleixner <tglx@linutronix.de>,
	efault@gmx.de, K Prateek Nayak <kprateek.nayak@amd.com>,
	John Stultz <jstultz@google.com>,
	Vincent Palomares <paillon@google.com>
Subject: Re: Very high scheduling delay with plenty of idle CPUs
Date: Fri, 8 Nov 2024 09:31:33 +0100	[thread overview]
Message-ID: <20241108083133.GD38786@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <CAGETcx830PZyr_oZAkghR=CLsThLUX1hZRxrNK_FNSLuF2TBAw@mail.gmail.com>

On Thu, Nov 07, 2024 at 11:28:07PM -0800, Saravana Kannan wrote:
> Hi scheduler folks,
> 
> I'm running into some weird scheduling issues when testing non-sched
> changes on a Pixel 6 that's running close to 6.12-rc5. I'm not sure if
> this is an issue in earlier kernel versions or not.
> 

It's a bit unfortunate you don't have a known good kernel there. Anyway,
one thing that recently came up is that DELAY_DEQUEUE can cause some
delays, specifically it can inhibit wakeup migration.

You can either test with that feature turned off, or apply something
like the following patch:

  https://lkml.kernel.org/r/20241106135346.GL24862@noisy.programming.kicks-ass.net

  reply	other threads:[~2024-11-08  8:31 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-11-08  7:28 Very high scheduling delay with plenty of idle CPUs Saravana Kannan
2024-11-08  8:31 ` Peter Zijlstra [this message]
2024-11-10  5:49   ` Saravana Kannan
2024-11-11  5:17     ` K Prateek Nayak
2024-11-11  6:15       ` Saravana Kannan
2024-11-11  8:25         ` Christian Loehle
2024-11-11  9:02           ` Saravana Kannan
2024-11-11  9:08             ` Christian Loehle
2024-11-11 10:40         ` Peter Zijlstra
2024-11-11 11:15           ` Vincent Guittot
2024-11-11 18:17             ` Saravana Kannan
2024-11-11 19:00               ` Vincent Guittot
2024-11-11 18:23           ` Saravana Kannan
2024-11-11 19:01             ` Vincent Guittot
2024-11-11 19:12               ` Vincent Guittot
2024-11-12  7:23                 ` Saravana Kannan
2024-11-12  9:03                   ` Vincent Guittot
2024-11-12 16:25                     ` Saravana Kannan
2024-11-12 17:00                       ` Vincent Guittot
2024-11-08  9:02 ` Vincent Guittot
2024-11-14  6:36   ` Saravana Kannan
2024-11-14 13:06     ` Vincent Guittot

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