Re: Performance monitoring units and KVM

Balaji Rao
2008-01-31T07:12:58Z

On Thursday 31 January 2008 08:42:32 am Andi Kleen wrote:
> On Thu, Jan 31, 2008 at 12:44:10AM +0530, Balaji Rao wrote:
> > On Wednesday 30 January 2008 11:56:25 pm Andi Kleen wrote:
> > > There is no really an architectural PMU if you consider
> > > boxes beyond relatively new Intel CPUs (which got one)
> >
> > But since kvm runs only on such CPUs, it should not really be a problem
> > in migrating between various Intel models at least.
>
> I'm not 100% sure, but I think there are P4 based (Family 15) CPUs which
> have VT but not ArchPerfMon. AFAIK ArchPerfMon is only in Family 6 CPUs.
> Family 15 has a completely different PerfMon interface.
>
Yea, you are right. To quote from the manual (2.1.7), 'Intel® Virtualization
Technology (Intel® VT) was introduced in the Intel Pentium 4 processor 672 and
662.' And they dont have ArchPerfMon as it was introduced only after core solo
and duo.

regards,
balaji rao