Re: Performance monitoring units and KVM

Andi Kleen
2008-01-30T18:05:43Z

> Is there really a requirement to profile several userspace programs, on
> several guests, simultaneously?

Since guests affect each others performance (e.g. one guest can push
the data of another guest out of cache) profiling over guests makes
a lot of sense. Otherwise you cannot easily diagnose any situations
where a guest affects another guests' performance negatively.

>The usual argument for profiling over gus
If not, passing through the PMU will
> work best, with the additional advantage that guests will not need
> modification (so you can run Windows with VTune, for example).

Ideally you would support both.

-Andi