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

["Shan, Haitao" <haitao.shan@xxxxxxxxx>]

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.

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.

Best Regards
Shan Haitao
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