Re: Guest OS CPU Clock

[Kirk Kosinski]

Hi, I believe this is normal.  The cpuinfo in a VM will have the
physical CPU speed and not the capped speed.  Did you try running a
benchmark to see if the CPU usage is capped?

Best regards,
Kirk

On 09/16/2014 07:47 PM, Vibranze Teh wrote:
> Hi Lists,
> 
> I found out that the guest OS CPU clock is not conforming to the one
> defined in compute offering.
> 
> In Compute Offerings, I defined 1GHz, 2 Cores and the CPU Cap is ticked,
> but when I did a 'cat /proc/cpuinfo' from guest OS, it shown my hypervisor
> physical CPU clock.
> 
> Is this behavior by design? How to really limit the guest OS to the one set
> in Compute Offering?
> 
> Thanks.
> 

Re: Guest OS CPU Clock

[Vibranze Teh]

Thanks Bret.

I was told this is by design as well. I'm fine with that but how do we
check if the guest OS really utilizing only the CPU clock given or defined
in compute offering?

Cheers,
Vibranze

On Wed, Sep 17, 2014 at 10:50 AM, Bret Mette 
wrote:

> As far as I know, Xen and kvm will not actually downgrade the clock speed
> to the guest, they will just attempt to make sure the guest does not get
> scheduled for more than it's share of the core's total power.
>
> Someone correct me if I am wrong please.
>
>
> > On Sep 16, 2014, at 7:47 PM, Vibranze Teh  wrote:
> >
> > Hi Lists,
> >
> > I found out that the guest OS CPU clock is not conforming to the one
> > defined in compute offering.
> >
> > In Compute Offerings, I defined 1GHz, 2 Cores and the CPU Cap is ticked,
> > but when I did a 'cat /proc/cpuinfo' from guest OS, it shown my
> hypervisor
> > physical CPU clock.
> >
> > Is this behavior by design? How to really limit the guest OS to the one
> set
> > in Compute Offering?
> >
> > Thanks.
>

Re: Guest OS CPU Clock

[Bret Mette]

As far as I know, Xen and kvm will not actually downgrade the clock speed to 
the guest, they will just attempt to make sure the guest does not get scheduled 
for more than it's share of the core's total power.

Someone correct me if I am wrong please.


> On Sep 16, 2014, at 7:47 PM, Vibranze Teh  wrote:
> 
> Hi Lists,
> 
> I found out that the guest OS CPU clock is not conforming to the one
> defined in compute offering.
> 
> In Compute Offerings, I defined 1GHz, 2 Cores and the CPU Cap is ticked,
> but when I did a 'cat /proc/cpuinfo' from guest OS, it shown my hypervisor
> physical CPU clock.
> 
> Is this behavior by design? How to really limit the guest OS to the one set
> in Compute Offering?
> 
> Thanks.