[fedora-virt] Clock jumping

[Orion Poplawski]

On 05/07/2010 08:56 AM, Glauber Costa wrote:
> On Thu, May 06, 2010 at 09:52:49PM -0600, Orion Poplawski wrote:
>> I've got a F13 kvm VM running under CentOS 5.4 and I'm seeing the clock
>> suddenly jump forward by about 10 hours.  I have no idea what is up.
>> Perhaps confusion about whether the rtc clock is utc or not?  (though
>> I'm in MDT which I think is 6 hours diff).  Any ideas?
>
> First important information, what's your clocksource in the guest?

# dmesg | grep -Fi clock
kvm-clock: cpu 0, msr 0:1ba4741, boot clock
kvm-clock: cpu 0, msr 0:1e15741, primary cpu clock
Switching to clocksource kvm-clock
rtc_cmos 00:01: setting system clock to 2010-05-04 09:19:27 UTC (1272964767)

> Are you suspending / resuming, stoping, or doing any tricks like that?

Nope.

> Do you have load on guest or host?

Guest is mostly idle,  running zabbix:

02:30:01 AM     CPU     %user     %nice   %system   %iowait    %steal 
   %idle
Average:        all      1.24      0.33      1.88      5.91      0.00 
   90.64

Host is mostly idle until 21:30 - 23:00 when it runs backups:

09:00:03 PM       CPU     %user     %nice   %system   %iowait    %steal 
     %idle
09:10:01 PM       all      0.05      0.61      2.45      5.11      0.00 
     91.78
09:20:02 PM       all      0.04      0.33      2.61      5.28      0.00 
     91.73
09:30:02 PM       all      0.04      0.53      2.59      5.08      0.00 
     91.75
09:40:03 PM       all     15.56      7.22      4.97      5.02      0.00 
     67.23
09:50:05 PM       all     48.39     17.79      8.56      3.75      0.00 
     21.50
10:00:02 PM       all     45.55     15.40      9.22      4.74      0.00 
     25.09
10:10:05 PM       all     46.53      7.75      9.18      7.12      0.00 
     29.42
10:20:04 PM       all     54.99      0.34      8.06      6.27      0.00 
     30.34
10:30:03 PM       all     46.53      0.47      8.76      7.68      0.00 
     36.57
10:40:03 PM       all     42.60      3.19      8.39      6.87      0.00 
     38.95
10:50:02 PM       all      1.68      4.78      3.56      9.91      0.00 
     80.07
11:00:03 PM       all      0.18      3.89      3.16     11.99      0.00 
     80.77
11:10:03 PM       all      0.10     15.74      4.80     12.13      0.00 
     67.23
11:20:03 PM       all      0.10     17.26      4.27     12.75      0.00 
     65.62
11:30:02 PM       all      0.07      5.21      2.90     19.83      0.00 
     71.99
11:40:03 PM       all      0.06      3.28      2.60     22.68      0.00 
     71.38
11:50:02 PM       all      0.17      4.10      1.81     11.91      0.00 
     82.01
Average:          all      2.65      0.81      1.88      1.77      0.00 
     92.89

-- 
Orion Poplawski
Technical Manager                     303-415-9701 x222
NWRA/CoRA Division                    FAX: 303-415-9702
3380 Mitchell Lane                  orion at cora.nwra.com
Boulder, CO 80301              http://www.cora.nwra.com