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Bug#599161: xen-linux-system-2.6.32-5-xen-amd64: Clock moved forward 50 minutes, caused Xen HVM domU restart



Hi,

No, unfortunately not. I just suffered it again aswell over the
Christmas break. Let me know if you find any fix.

Regards,
Mark

On Sun, Dec 26, 2010 at 12:50:26PM +0100, Moritz Muehlenhoff wrote:
> On Wed, Oct 06, 2010 at 12:05:18PM +0100, Mark Adams wrote:
> 
> > > > As this is when the clock went from 18:00 to 18:50 and started the chain
> > > > of events (restarted the 2008 domU). Any ideas why this log occurred?
> > > 
> > > The TSC appeared to go backwards by a fairly significant amount, which
> > > has upset the kernel.
> > > 
> > > The behaviour of the virtual TSC as seen by an HVM guest is controlled
> > > by a combination of the tsc_mode setting in your domain configuration
> > > and, I think, by the features of your specific hardware (some have
> > > constant rate TSC, others advertise varying levels of synchronisation
> > > between cores etc). It's then up to the guest kernel whether it even
> > > uses TSC as a timesource at all and how it handles instability etc and
> > > how it derives other time sources (such as the wallclock time) from it.
> > > 
> > > Sorry this isn't more helpful, but as I say you will probably get better
> > > answers on one of the Xen mailing lists.
> > 
> > Hi Ian,
> > 
> > Thanks for your notes. I've already tried the xen-users list so I will
> > try xen-devel to see if I can glean any more information about my issue.
> > I will update the report here when I get any more information.
> 
> Did you contact them? From what I read from the bug report so far, running
> an NTP client in the HVM host should suffice.
> 
> Cheers,
>         Moritz




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