Re: [Xen-devel] Problems with enabling hypervisor C and P-state control

["Niraj Tolia" <ntolia@xxxxxxxxx>]

On Thu, Oct 23, 2008 at 10:59 PM, Yu, Ke <ke.yu@xxxxxxxxx> wrote:
> After discussing with Jinsong, we got the root cause. You are right, this is 
> xen pm statistics logic issue. when the coordination type is SW_ANY, we only 
> record the first CPU cpufreq change, the other 3 cores within the same 
> dependency domain is ignored, so you only see one core changes every 
> dependency domain.
>
> The attached patch fix  this issue. could you please have a try? If it works 
> in your platform, we will send out for applying in upstream.

I just applied the patch and while xenpm might be doing the right
thing, I am not completely sure. For example, if I launch a single
VCPU VM, pin it to a core, and launch a CPU intensive task on it, ALL
four cores on the socket are reported to switch into P0. However, from
what I understand about this processor (Xeon E7330), only two of them
should. Like vanilla Linux, the other two should be able to operate at
independent voltage/frequency settings. Once again, I am not sure if
this is xenpm's fault or if the underlying frequency control code
isn't able to determine what  CPUs need to switch frequency at the
same time.

Cheers,
Niraj

-- 
Niraj Tolia, Researcher, HP Labs
http://www.hpl.hp.com/personal/Niraj_Tolia/

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