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From: Peter Zijlstra <peterz@infradead.org>
To: Dimitri Sivanich <sivanich@sgi.com>
Cc: linux-kernel@vger.kernel.org, tony.luck@intel.com,
	Ingo Molnar <mingo@elte.hu>, Mike Galbraith <efault@gmx.de>,
	Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>,
	Gregory Haskins <ghaskins@novell.com>, Greg KH <greg@kroah.com>,
	Nick Piggin <npiggin@suse.de>, Robin Holt <holt@sgi.com>
Subject: Re: 2.6.27.8 scheduler bug - threads not being scheduled for long periods
Date: Tue, 06 Jan 2009 08:36:26 +0100	[thread overview]
Message-ID: <1231227386.11687.23.camel@twins> (raw)
In-Reply-To: <20090105230218.GC20319@sgi.com>

On Mon, 2009-01-05 at 17:02 -0600, Dimitri Sivanich wrote:
> Peter,
> 
> On Mon, Jan 05, 2009 at 04:36:21PM -0600, Dimitri Sivanich wrote:
> > And sure enough, the rq->clock is sometimes going backwards.
> > 
> > The comment for sched_clock() in arch/ia64/kernel/head.S:
> >  * Return a CPU-local timestamp in nano-seconds.  This timestamp is
> >  * NOT synchronized across CPUs its return value must never be
> >  * compared against the values returned on another CPU.  The usage in
> >  * kernel/sched.c ensures that.
> > 
> > We will try this with CONFIG_HAVE_UNSTABLE_SCHED_CLOCKS.
> >
> 
> The testcase does indeed run with CONFIG_HAVE_UNSTABLE_SCHED_CLOCKS configured.

Ok, glad it worked out, thanks!

      reply	other threads:[~2009-01-06  7:36 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-01-05 17:56 2.6.27.8 scheduler bug - threads not being scheduled for long periods Dimitri Sivanich
2009-01-05 18:44 ` Gregory Haskins
2009-01-05 18:51   ` Dimitri Sivanich
2009-01-05 18:59     ` Gregory Haskins
2009-01-14 22:34       ` kenneth johansson
2009-01-05 20:55 ` Peter Zijlstra
2009-01-05 21:54   ` Dimitri Sivanich
2009-01-05 22:36     ` Dimitri Sivanich
2009-01-05 23:02       ` Dimitri Sivanich
2009-01-06  7:36         ` Peter Zijlstra [this message]

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