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From: Ingo Molnar <mingo@kernel.org>
To: David Ahern <dsahern@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Mike Galbraith <efault@gmx.de>
Subject: Re: deadlock in scheduler enabling HRTICK feature
Date: Fri, 28 Jun 2013 11:00:21 +0200	[thread overview]
Message-ID: <20130628090021.GA25431@gmail.com> (raw)
In-Reply-To: <51CCBCA9.1000200@gmail.com>


* David Ahern <dsahern@gmail.com> wrote:

> On 6/27/13 4:43 AM, Peter Zijlstra wrote:
> >On Wed, Jun 26, 2013 at 10:46:33AM -0600, David Ahern wrote:
> >>On 6/26/13 1:05 AM, Peter Zijlstra wrote:
> >>>>What is the expectation that the feature provides? not a whole lot of
> >>>>documentation on it. I walked down the path wondering if it solved an odd
> >>>>problem we are seeing with the CFS in 2.6.27 kernel.
> >>>
> >>>Its supposed to use hrtimers for slice expiry instead of the regular tick.
> >>
> >>So theoretically CPU bound tasks would get preempted sooner? That was my
> >>guess/hope anyways.
> >
> >Doth the below worketh?
> 
> It doth.
> 
> Usually make -j 8 for a kernel build in a VM would lock it up pretty
> quickly. With the patch I was able to run full builds multiple
> times.
> 
> As for the solution you are avoiding the nesting by not waking up
> the softirq daemon.

I guess we could merge this fix?

Thanks,

	Ingo

  reply	other threads:[~2013-06-28  9:00 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-06-25 21:05 deadlock in scheduler enabling HRTICK feature David Ahern
2013-06-25 21:17 ` Peter Zijlstra
2013-06-25 21:20   ` David Ahern
2013-06-26  7:05     ` Peter Zijlstra
2013-06-26 16:46       ` David Ahern
2013-06-27 10:43         ` Peter Zijlstra
2013-06-27 10:53           ` Peter Zijlstra
2013-06-27 12:28             ` Mike Galbraith
2013-06-27 13:06             ` Ingo Molnar
2013-06-27 19:18             ` Andy Lutomirski
2013-06-27 20:37               ` Peter Zijlstra
2013-06-27 22:28           ` David Ahern
2013-06-28  9:00             ` Ingo Molnar [this message]
2013-06-28  9:18               ` Peter Zijlstra
2013-07-12 13:29                 ` [tip:sched/core] sched: Fix HRTICK tip-bot for Peter Zijlstra
2013-06-28  9:09             ` deadlock in scheduler enabling HRTICK feature Peter Zijlstra
2013-06-28 17:28               ` David Ahern

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