On Wed, May 11, 2011 at 11:55:28AM -0400, Avi Kivity wrote: > This not-for-merging patchset exposes an emulated version 1 architectural > performance monitoring unit to KVM guests. The PMU is emulated using > perf_events, so the host kernel can multiplex host-wide, host-user, and the > guest on available resources. > > Caveats: > - counters that have PMI (interrupt) enabled stop counting after the > interrupt is signalled. This is because we need one-shot samples > that keep counting, which perf doesn't support yet > - some combinations of INV and CMASK are not supported > - counters keep on counting in the host as well as the guest > - the RDPMC instruction and CR4.PCE bit are not yet emulated > - there is likely a bug in the implementation; running 'perf top' in > a guest that spends 80% of its time in userspace shows perf itself > as consuming almost all cpu > > perf maintainers: please consider the first three patches for merging (the > first two make sense even without the rest). If you're familiar with the Intel > PMU, please review patch 5 as well - it effectively undoes all your work > of abstracting the PMU into perf_events by unabstracting perf_events into what > is hoped is a very similar PMU. Gaah, I was just about to submit a talk about PMU virtualization for KVM Forum :) Anyway, I thought about a paravirt-approach instead of implementing a real PMU... But there are certainly good reasons for both. 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
