Re: S3 sleep in dom0 breaks dom0<->domU wallclock synchronization

[Keir Fraser <keir.fraser@eu.citrix.com>]

On 01/07/2010 04:04, "Rafal Wojtczuk" <rafal@invisiblethingslab.com> wrote:

> Hello,
> xen-3.4.3 x86_64, dom0 2.6.34-9.xenlinux as dom0,
> 2.6.32.14-1.2.105.pvops0 in PV domU. /proc/sys/xen/independent_wallclock is
> 0.
> After resume from S3 sleep in dom0, the wall clock in domU is
> desynchronized from dom0's one (the delta is the length of S3 sleep). It
> does not seem that adj_timex is in progress (the delta is constant in time).
> 
> Is it a known issue ? If so, could someone point me to a solution ?

I think that pv_ops domU kernels pick up Xen's wallclock at boot time, but
won't listen for updates thereafter. So if you ran a non-pv_ops domU, you'd
probably find that its wallclock would be correctly updated after S3. Cc'ing
Jeremy as he'll be able to confirm this. I think his answer will be that you
should run ntp in every guest, but I'm not sure how that will react to
unexpected warps in time.

 -- Keir

> Regards,
> Rafal Wojtczuk
> 
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