Re: KVM PMU virtualization

[Zachary Amsden <zamsden@redhat.com>]

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.