From mboxrd@z Thu Jan  1 00:00:00 1970
From: Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH] sched/fair: schedutil: update only with all info
 available
Date: Wed, 11 Apr 2018 18:15:48 +0200
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To: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Patrick Bellasi <patrick.bellasi@arm.com>, linux-kernel <linux-kernel@vger.kernel.org>, "open list:THERMAL" <linux-pm@vger.kernel.org>, Ingo Molnar <mingo@redhat.com>, "Rafael J . Wysocki" <rafael.j.wysocki@intel.com>, Viresh Kumar <viresh.kumar@linaro.org>, Juri Lelli <juri.lelli@redhat.com>, Joel Fernandes <joelaf@google.com>, Steve Muckle <smuckle@google.com>, Dietmar Eggemann <dietmar.eggemann@arm.com>, Morten Rasmussen <morten.rasmussen@arm.com>
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On Wed, Apr 11, 2018 at 06:10:47PM +0200, Vincent Guittot wrote:
> > Could is be that for some reason the nohz balancer now takes a very long
> > time to run?
> 
> Heiner mentions that is was a relatively slow celeron and he uses
> ondemand governor. So I was about to ask him to use performance
> governor to see if it can be because cpu runs slow and takes too muche
> time to enter idle

Maybe also hand him a patch with some trace_printk()s in and ask him to
send /debug/tracing/trace after it happens or somesuch. Maybe we can
find a clue that way.