Re: KVM PMU virtualization

Joerg Roedel
2010-02-26T10:39:35Z

On Fri, Feb 26, 2010 at 11:46:34AM +0200, Avi Kivity wrote:
> On 02/26/2010 10:42 AM, Ingo Molnar wrote:
>> Note that the 'soft PMU' still sucks from a design POV as there's no generic
>> hw interface to the PMU. So there would have to be a 'soft AMD' and a 'soft
>> Intel' PMU driver at minimum.
>>
>
> Right, this will severely limit migration domains to hosts of the same
> vendor and processor generation. There is a middle ground, though,
> Intel has recently moved to define an "architectural pmu" which is not
> model specific. I don't know if AMD adopted it. We could offer both
> options - native host capabilities, with a loss of compatibility, and
> the architectural pmu, with loss of model specific counters.

I only had a quick look yet on the architectural pmu from intel but it
looks like it can be emulated for a guest on amd using existing
features.

Joerg