[sles-beta] A Problem with KVM Guest ?

Günther J. Niederwimmer gjn at gjn.priv.at
Thu Sep 4 08:35:29 MDT 2014


Hello Antoine,

Am Donnerstag, 4. September 2014, 16:23:29 schrieb Antoine Ginies:
> Günther J. Niederwimmer:
> > Am Donnerstag, 4. September 2014, 13:57:01 schrieb 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.
> > 
> > I mean we miss understand  use
> > 
> > The behind is from a CLIENT
> 
> kvm-clock clocksource is for the VM guest.
> 
> > This is from the HOST !!
> 
> The host doesn't provide kvm-clock source:
> -----------------------------------------
> root # cat
> /sys/devices/system/clocksource/clocksource0/available_clocksource tsc hpet
> acpi_pm
> -----------------------------------------
> 
> It's tsc by default.
> So everything is ok.

:-))).

why I have then a wrong Time !

anything must be wrong, the question is what?

> >  dmesg | grep clocksource
> > 
> > [    0.560063] Switched to clocksource hpet
> > [    2.329666] tsc: Refined TSC clocksource calibration: 3700.000 MHz
> > [    3.645349] Switched to clocksource tsc
> > 
> > and I like to change this for Tests.
> > 
> > > ------------
> > > 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.
> > 
> > Have I to open a SR ?

-- 
mit freundlichen Grüßen / best Regards,

  Günther J. Niederwimmer


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