RE: [Xen-devel] Timer ISR/0: Timer went backwards error...

["Dan Magenheimer" <dan.magenheimer@xxxxxxxxxx>]

Sandesh --

hpet_force was a Xen parameter in Dave Winchell's last hpet
patch that hasn't yet been accepted into the tree.  However
I think it would have only worked on hvm guests.

Xen system time's dependency on tsc is most susceptible on
pre-Barcelona SMP AMD boxes (where tsc isn't synchronized
between processors), though yours seems to have a very
bad skew.  As Keir suggests "clocksource=hpet" as
a Xen command line parameter will hopefully
work for those boxes.

Dan

> -----Original Message-----
> From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
> [mailto:xen-devel-bounces@xxxxxxxxxxxxxxxxxxx]On Behalf Of Keir Fraser
> Sent: Thursday, July 03, 2008 6:30 AM
> To: Sandesh; xen-devel@xxxxxxxxxxxxxxxxxxx
> Subject: Re: [Xen-devel] Timer ISR/0: Timer went backwards error...
> 
> 
> hpet_force=1 means nothing to Xen. To see what platform timer 
> is being used,
> look for a line 'Platform timer is <foo>' in Xen's boot 
> output. To change
> it, specify for example 'clocksource=hpet' as a Xen boot parameter.
> 
> Could you also send a few of the 'went backwards' messages, 
> so we can see
> how badly time is getting skewed. Perhaps we can work out 
> where the issue
> arises from too -- it seems that a significant proprotion of 
> those who have
> issues with these messages are seeing them on AMD boxes. I 
> haven't confirmed
> the correlation though.
> 
>  -- Keir
> 
> On 3/7/08 12:44, "Sandesh" <sandesh.ahiremath@xxxxxxxxx> wrote:
> 
> > Hi all,
> >   I am getting lots of Timer ISR/0: Timer went backwards error...
> > due to which my dom0 is crashing. I tried hpet_force=1 
> argument for xen
> > command line even then the problem presists. Other than 
> that i could not
> > find any solution on the net.
> >   Has this problem been resolved??
> >
> > Iam using AMD Athlon(tm) 64bit processor, installed with FC6 &
> > xen-3.2.0.
> >
> > Thanks,
> >   Sandesh
> >
> >
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