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From: Ingo Molnar <mingo@kernel.org>
To: Alexey Vlasov <renton@renton.name>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Ingo Molnar <mingo@elte.hu>, Mike Galbraith <bitbucket@online.de>,
	linux-kernel@vger.kernel.org
Subject: Re: Kernel migration eat CPUs
Date: Thu, 5 Sep 2013 13:12:52 +0200	[thread overview]
Message-ID: <20130905111252.GA23362@gmail.com> (raw)
In-Reply-To: <20130904185315.GB13294@beaver>


* Alexey Vlasov <renton@renton.name> wrote:

> On Sun, Aug 25, 2013 at 04:28:37PM +0200, Peter Zijlstra wrote:
> 
> > and a function (or function-graph)
> > trace for when this happens?
> 
> Unfortunately I could not make trace.
> First when migration threads start to eat CPUs and when I turn on trace:
> # echo function > current_tracer
> # echo 1 > tracing_on
> then server is down at once. LA comes up to several thousands, it stops
> to receive commands. Sometimes I even have to reboot it.

Could you try the latest -tip tree at:

   git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git

In particular this fix:

   5a8e01f8fa51 sched/cputime: Do not scale when utime == 0

Could perhaps fix the phantom CPU overhead you are seeing?

Thanks,

	Ingo

  reply	other threads:[~2013-09-05 11:12 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20130823151711.f4c1f596b4c7aa1eecccc9a6@linux-foundation.org>
     [not found] ` <20130825142837.GD31370@twins.programming.kicks-ass.net>
2013-08-29 10:10   ` Kernel migration eat CPUs Alexey Vlasov
2013-09-04 18:53   ` Alexey Vlasov
2013-09-05 11:12     ` Ingo Molnar [this message]
2013-09-11 15:18       ` Alexey Vlasov
2013-10-10  7:13         ` Alexey Vlasov
2013-08-22 15:00 Alexey Vlasov
2013-08-29  7:31 ` Mike Galbraith

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