Re: [Xen-users] Time went backwards

["Oliver Rojo" <orojo@xxxxxxxxxxxx>]

Wow that did the trick!

Thanks a lot!

----- Original Message -----
From: Olivier LAMBERT
[mailto:lambert.olivier@xxxxxxxxx]
To: Oliver Rojo
[mailto:orojo@xxxxxxxxxxxx]
Cc: xen-users@xxxxxxxxxxxxxxxxxxx
Sent: Wed, 17
Feb 2010 08:32:44 +0000
Subject: Re: [Xen-users] Time went backwards


> Please read this :
> If a domU crashes or freezes while uttering the famous lasts words
> 'clocksource/0: Time went backwards', your domU is likely using the
> xen clocksource instead of its own clock ticks. In practice, this
> seems to be the cause of infrequent lockups under load (and/or
> problems with suspending). A workaround is to decouple the clock in
> the domU from the dom0:
> 
> In your dom0 and domU /etc/sysctl.conf add the line:
> xen.independent_wallclock=1. On the dom0, edit the configuration file
> of the domU (e.g. /etc/xen/foobar.cfg and add (or expand) the
> extra-line: extra="clocksource=jiffies".
> 
> These settings can be activated without rebooting the domU. After
> editing the configuration files, issue sysctl -p and echo "jiffies">
> /sys/devices/system/clocksource/clocksource0/current_clocksource on
> the domU prompt.
> 
> Because the clock won't be relying on the dom0 clock anymore, you
> probably need to use ntp on the domU to synchronize it properly to the
> world.
> 
> 
> 
> Olivier.
> XO Project
> http://xen-orchestra.com
> 
> On Wed, Feb 17, 2010 at 9:05 AM, Oliver Rojo <orojo@xxxxxxxxxxxx> wrote:
> > I am receiving lots of messages like these on my xen virtual machines:
> >
> > Feb 17 06:57:54 XXX-vm kernel: [61138.593289] __ratelimit: 138 messages
> suppressed
> > Feb 17 06:57:54 XXX-vm kernel: [61138.593289] clocksource/0: Time went
> backwards: ret=3b05d54bddc delta=-65371689384312 shadow=3b05d288427
> offset=2c75df
> > Feb 17 06:57:54 XXX-vm kernel: [61138.593289] __ratelimit: 133 messages
> suppressed
> > Feb 17 06:57:54 XXX-vm kernel: [61138.593289] clocksource/0: Time went
> backwards: ret=3b188b7d968 delta=-65366666501612 shadow=3b1872eab3b
> offset=18978b8
> > Feb 17 06:57:54 XXX-vm kernel: [61138.593289] __ratelimit: 97 messages
> suppressed
> > Feb 17 06:57:54 XXX-vm kernel: [61138.593289] clocksource/0: Time went
> backwards: ret=3b2b910bbd2 delta=-65361560402818 shadow=3b2b134cf7a
> offset=7dc452f
> > Feb 17 06:57:54 XXX-vm kernel: [61138.593289] __ratelimit: 198 messages
> suppressed
> > Feb 17 06:57:54 XXX-vm kernel: [61138.593289] clocksource/0: Time went
> backwards: ret=3b3dabe5629 delta=-65356700410155 shadow=3b39fa01ee9
> offset=3b1e7453
> > Feb 17 06:57:54 XXX-vm kernel: [61138.593290] __ratelimit: 425 messages
> suppressed
> > Feb 17 06:57:54 XXX-vm kernel: [61138.593290] clocksource/0: Time went
> backwards: ret=3b505b86c49 delta=-65351684410123 shadow=3b505410ae9
> offset=77a3ab
> >
> > What do these messages indicate? Did I missed something on my setup?
> >
> > Oliver
> >
> > _______________________________________________
> > Xen-users mailing list
> > Xen-users@xxxxxxxxxxxxxxxxxxx
> > http://lists.xensource.com/xen-users
> >
> 
> _______________________________________________
> Xen-users mailing list
> Xen-users@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-users
> 

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