[sles-beta] A Problem with KVM Guest ?

[Antoine Ginies]

Günther J. Niederwimmer:
> Am Donnerstag, 4. September 2014, 12:24:02 schrieb Antoine Ginies:
> > Günther J. Niederwimmer:
> > > Hello,
> > > I found a Problem with KVM_clock?
> > > on my Installation I have a KVM Server and KVM Clients all SLES 12 Server
> > > The KVM Host have a NTP Server configured and have a correct time
> > > 
> > > date
> > > Don Sep  4 12:00:19 CEST 2014
> > > all clients have this Time
> > > date
> > > Don Sep  4 02:15:24 CEST 2014
> > > 
> > > the timezone is correct but the time is wrong ?
> > 
> > Hello,
> > Can you check that your VM is currently using kvm_clock?
> 
> akerb:~ # dmesg | grep kvm-clock
> [    0.000000] kvm-clock: Using msrs 4b564d01 and 4b564d00
> [    0.000000] kvm-clock: cpu 0, msr 1:3ff18001, boot clock
> [    0.000000] kvm-clock: cpu 0, msr 1:3ff18001, primary cpu clock
> [    0.004000] kvm-clock: cpu 1, msr 1:3ff18041, secondary cpu clock
> [    0.004000] kvm-clock: cpu 2, msr 1:3ff18081, secondary cpu clock
> [    0.004000] kvm-clock: cpu 3, msr 1:3ff180c1, secondary cpu clock
> [    0.134685] Switched to clocksource kvm-clock
> 
> This is the client
> 
> root# cat /sys/devices/system/clocksource/clocksource0/current_clocksource

You forget the value, but according to dmesg it was kvm-clock at
0.134685 until something else has switched to another value.

------------
root # dmesg | grep clocksource
------------
will let you know if there is any change.


> I have on the Server
> tsc
> 
> This is a original YaSt Installation
> 
> can I change this manual ?

On VM guest you can change it with echo:
----------
echo tsc > /sys/devices/system/clocksource/clocksource0/current_clocksource
echo kvm-clock > /sys/devices/system/clocksource/clocksource0/current_clocksource
----------

You should see a dmesg in the console of your VM guest saying that
clocksource has switched.


-- 
Antoine Ginies <aginies at suse.com>
Project Manager
SUSE France