Re: KVM PMU virtualization

Zachary Amsden
2010-03-01T19:04:35Z

On 02/26/2010 05:55 AM, Peter Zijlstra wrote:
> On Fri, 2010-02-26 at 17:11 +0200, Avi Kivity wrote:
>
>> On 02/26/2010 05:08 PM, Peter Zijlstra wrote:
>>
>>>> That's 7 more than what we support now, and 7 more than what we can
>>>> guarantee without it.
>>>>
>>>>
>>> Again, what windows software uses only those 7? Does it pay to only have
>>> access to those 7 or does it limit the usability to exactly the same
>>> subset a paravirt interface would?
>>>
>>>
>> Good question. Would be interesting to try out VTune with the non-arch
>> pmu masked out.
>>
> Also, the ANY bit is part of the intel arch pmu, but you still have to
> mask it out.
>
> BTW, just wondering, why would a developer be running VTune in a guest
> anyway? I'd think that a developer that windows oriented would simply
> run windows on his desktop and VTune there.
>

What if you want to run on 10 different variations of Windows 32 / 64 /
server / desktop configurations. Do you maintain 10 installed pieces of
hardware?

A virtual machine is a better solution. And you might want to
performance tune all 10 of those configurations as well. Be nice if it
were possible.