Re: [XEN-3.4] pv_ops dom0 time/clock handling

[Jeremy Fitzhardinge <jeremy@goop.org>]

Daniel Schroeder wrote:
> Wed May 27 09:33:12 CEST 2009
> Mi Mai 27 11:33:13 CEST 2009
>   

That does look like some kind of TZ issue, but I'm not sure where it 
would be.

> btw: i have checked with 32 bit pvops and 64 bit pvops dom0 and the time
>  in the domU is correct with the 64bit pvops dom0 kernel...this wasnt
> the same domU...so, next step for me, is to copy the domU to the 64bit
> system and try again...to verify, that this only happens for me with
> 32bit pvops dom0...
>   

How odd.

>> One difference between pvops time handling and the -xen kernels, is that
>> they defaulted to slaving the domU time off the hypervisor at all times,
>> so a system time change would propagate into guests.  I don't implement
>> that in pvops kernels, so they'll maintain independent time unless you
>> explicitly sync with some mechanism like ntp.
>>     
> hmm...does this mean, that i have to use ntp in domU if i use the pvops
> kernel? Because time changes in dom0 doesnt propagate into domUs?
>   

It will set its initial time-of-day clock from the hypervisor's at boot, 
but then proceed independently (but the timebase is derived from the 
hypervisor's clock).  If you want it to track a reference, you need to 
run ntp.

    J