On Thu, 2010-02-25 at 18:34 +0100, Joerg Roedel wrote: > On Thu, Feb 25, 2010 at 04:04:28PM +0100, Jes Sorensen wrote: > > > 1) Add support to perf to allow it to monitor a KVM guest from the > > host. > > This shouldn't be a big problem. The PMU of AMD Fam10 processors can be > configured to count only when in guest mode. Perf needs to be aware of > that and fetch the rip from a different place when monitoring a guest. The idea is we want to measure both host and guest at the same time, and compare all the hot functions fairly. > > > 2) Allow guests access to the PMU (or an emulated PMU), making it > > possible to run perf on applications running within the guest. > > The biggest problem I see here is teaching the guest about the available > events. The available event sets are dependent on the processor family > (at least on AMD). > A simple approach would be shadowing the perf msrs which is a simple > thing to do. More problematic is the reinjection of performance > interrupts and performance nmis. > > I personally don't like a self-defined event-set as the only solution > because that would probably only work with linux and perf. I think we > should have a way (additionally to a soft-event interface) which allows > to expose the host pmu events to the guest. > > Joerg > -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
