RE: [PATCH V5 1/2] perf ignore LBR and extra_regs

Liang, Kan
2014-07-14T13:44:54Z

> -----Original Message-----
> From: Paolo Bonzini [mailto:pbonzini@redhat.com]
> Sent: Monday, July 14, 2014 9:40 AM
> To: Liang, Kan; Peter Zijlstra
> Cc: andi@firstfloor.org; linux-kernel@vger.kernel.org; kvm@vger.kernel.org
> Subject: Re: [PATCH V5 1/2] perf ignore LBR and extra_regs
>
> Il 14/07/2014 15:36, Liang, Kan ha scritto:
> >> > Kan Liang, what happens if CONFIG_PARAVIRT=y? Do you get garbage
> >> > or just no events reported?
> >> >
> > Guest rdmsr/wrmsr will eventually call rdmsr_safe/wrmsr_safe. They will
> handle the #GP. So there is no error report in guest.
>
> Yeah, but what's the effect on the output of perf?

They can be still counted/sampled, but the results are garbage.

Kan

>
> Paolo