Re: [Xen-devel] RE: intel core2 full virtualized performance counters

[Dietmar Hahn <dietmar.hahn@xxxxxxxxxxxxxx>]

> Dietmar Hahn wrote:
> > Hi list,
> >
> > i played around with the full virtualized performance counters (vpmu
> > stuff) on intel core2 processors in a HVM guest.
> > I got something to work on the processor family=6 and model=15. But
> > with newer processors (model=26 -> E5520 and model=29 -> X7460)
> > nothing happens.
> > I searched a little bit in the sources and found in vpmu_initialise()
> > that only for model 15 and 23 the  vpmu->arch_vpmu_ops gets
> > initialized.
> > Is this missing or do I something wrong? Maybe anybody is working on
> > this? Thanks in advance for all hints!
> >
> > Dietmar.
>
> The performance monitor facilities differ across CPU models. At the time
> vpmu is developed, model 15 and model 23 are the only two  models that are
> supported. The vpmu is designed to work with model-specific hanlding code.
> But actually no one adds new support for newer generation of CPUs.

This is a little bit surprising for me because I thought Intel did this for 
using their performance analyzer software such as vtune in HVM guest.

>
> I do not know how much differences between Core 2 PMU and Core i7. If you
> only collect performance data using architectural performance counters and
> events, I think it would be easy for you to hack the code in
> vpmu_initialize a bit to get it work.

Yes I did this and it works. Thanks.

Dietmar.

>
> Best Regards
> Shan Haitao

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