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Date:   Mon, 23 Nov 2020 19:13:13 +0100
From:   Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To:     Qian Cai <cai@redhat.com>
Cc:     Valentin Schneider <valentin.schneider@arm.com>,
        Peter Zijlstra <peterz@infradead.org>, tglx@linutronix.de,
        mingo@kernel.org, linux-kernel@vger.kernel.org,
        qais.yousef@arm.com, swood@redhat.com, juri.lelli@redhat.com,
        vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
        rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de,
        bristot@redhat.com, vincent.donnefort@arm.com, tj@kernel.org,
        ouwen210@hotmail.com
Subject: Re: [PATCH v4 11/19] sched/core: Make migrate disable and CPU
 hotplug cooperative
Message-ID: <20201123181313.ug4fwjcqnmbvo3f2@linutronix.de>
References: <20201023101158.088940906@infradead.org>
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On 2020-11-18 09:44:34 [-0500], Qian Cai wrote:
> On Tue, 2020-11-17 at 19:28 +0000, Valentin Schneider wrote:
> > We did have some breakage in that area, but all the holes I was aware of
> > have been plugged. What would help here is to see which tasks are still
> > queued on that outgoing CPU, and their recent activity.
> > 
> > Something like
> > - ftrace_dump_on_oops on your kernel cmdline
> > - trace-cmd start -e 'sched:*'
> >  <start the test here>
> > 
> > ought to do it. Then you can paste the (tail of the) ftrace dump.
> > 
> > I also had this laying around, which may or may not be of some help:
> 
> Once I have found a reliable reproducer, I'll report back.

any update?

Sebastian