Re: [tip:perfcounters/core] perf_counter, x86: remove X86_FEATURE_ARCH_PERFMON flag for AMD cpus

Ingo Molnar
2009-05-11T12:06:13Z

* Jaswinder Singh Rajput <jaswinder@kernel.org> wrote:

> On Mon, 2009-05-11 at 12:02 +0200, Ingo Molnar wrote:
> > * Jaswinder Singh Rajput <jaswinder@kernel.org> wrote:
> >
> > > There is one more way to check performance monitor support for
> > > Intel by using IA32_MISC_ENABLE MSR (0x1A0) bit 7 tells whether
> > > performance monitoring is available or not.
> > >
> > > But IA32_MISC_ENABLE MSR (0x1A0) is not available for Pentium and
> > > P6.
> > >
> > > So better I will add new cpufeature for performance monitoring for
> > > x86:
> > >
> > > X86_FEATURE_PERFMON : Performance monitor support
> >
> > What is the exact wording of IA32_MISC_ENABLE bit 7 in the Intel
> > documents?
> >
>
> Bit 7: Performance Monitoring Available. (R)
> 1 = Performance monitoring enabled
> 0 = Performance monitoring disabled

i guess, if 'perfmon' is not used yet ('arch_perfmon' is), we could
add this as a separate, new cpu features flag.

Although the confusion factor is high ...

Ingo