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

[Daniel Schroeder <sec@xxxxxxxxxxxxxxx>]

Jeremy Fitzhardinge wrote:
> Daniel Schroeder wrote:
>>>> this works for OpenSUSE 2.6.29.X XEN dom0 Kernel...
>>>> ...i have tested latest git-next repo .30-rc6 and the pv domU is two
>>>> hours ahead.
>>>> I have checked the following:
>>>>
>>>> dom0 ntpd working, correct time and /etc/localtime is correct
>>>> (Europe/Berlin)
>>>>
>>>> domU no ntpd and correct timezone and /etc/localtime (Europe/Berlin)
>>>> "localtime = 0" in pv domU config file...
>>>>
>>>> it seems to me, that the domU gets not UTC as basetime...
>>>>       
>>> This could plausibly be a pv_ops bug. I fthe only thing you change is
>>> the
>>> kernel -- keeping all configuration the same -- then dom0 will be
>>> providing
>>> exactly the same time info to both kernels.
>>>
>>>     
>> checked with OpenSUSE 2.6.29.X xenified dom0...pv domU has the right
>> time...booted pvops .30-rc6, pv domU gets probably localtime as
>> basetime, so domU is two hours in the future...
>>   
> 
> Time is pretty straightforward, and there's no TZ calculation involved
> at any points.  Its hard to see how you'd get a two hour delta (is it
> exactly 2 hours?).

Wed May 27 09:33:12 CEST 2009
Mi Mai 27 11:33:13 CEST 2009

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...
> 
> 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?

Daniel

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel