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From: Ingo Molnar <mingo@elte.hu>
To: Alok Kataria <akataria@vmware.com>
Cc: the arch/x86 maintainers <x86@kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Zach Amsden <zach@vmware.com>
Subject: Re: x86, vmi: TSC going backwards check in vmi clocksource
Date: Thu, 19 Feb 2009 19:11:32 +0100	[thread overview]
Message-ID: <20090219181132.GA11477@elte.hu> (raw)
In-Reply-To: <1235066638.23293.7.camel@alok-dev1>


* Alok Kataria <akataria@vmware.com> wrote:

> On Thu, 2009-02-19 at 03:18 -0800, Ingo Molnar wrote:
> > * Alok Kataria <akataria@vmware.com> wrote:
> > 
> > > From: Alok N Kataria <akataria@vmware.com>
> > > 
> > > Similar to the check for TSC going backwards in the TSC 
> > > clocksource, we also need this check for VMI clocksource.
> > 
> > ok. Precisely what kind of bug/symptoms does this fix?
> 
> If the read CYCLES_REAL counter value is less than the cycle_last value,
> it may result in time jumps.
> I also saw some messages about  process being stuck for more than
> 120sec, which was traced back to this.

Applied to tip:x86/urgent, thanks Alok!

	Ingo

  reply	other threads:[~2009-02-19 18:11 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-02-18 20:33 x86, vmi: TSC going backwards check in vmi clocksource Alok Kataria
2009-02-19 11:18 ` Ingo Molnar
2009-02-19 18:03   ` Alok Kataria
2009-02-19 18:11     ` Ingo Molnar [this message]
2009-02-20 17:58 ` Ingo Molnar
2009-02-20 18:23   ` Alok Kataria
2009-02-20 18:31     ` Ingo Molnar

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