Re: [RFC] para virt interface of perf to support kvm guest os statisticscollection in guest os

From: Avi Kivity
Date: Wed Jun 09 2010 - 05:00:14 EST

On 06/09/2010 06:30 AM, Zhang, Yanmin wrote:
From: Zhang, Yanmin<yanmin_zhang@xxxxxxxxxxxxxxx>

Based on Ingo's idea, I implement a para virt interface for perf to support
statistics collection in guest os. That means we could run tool perf in guest
os directly.

Great thanks to Peter Zijlstra. He is really the architect and gave me architecture
design suggestions. I also want to thank Yangsheng and LinMing for their generous

The design is:

1) Add a kvm_pmu whose callbacks mostly just calls hypercall to vmexit to host kernel;
2) Create a host perf_event per guest perf_event;
3) Host kernel syncs perf_event count/overflows data changes to guest perf_event
when processing perf_event overflows after NMI arrives. Host kernel inject NMI to guest
kernel if a guest event overflows.
4) Guest kernel goes through all enabled event on current cpu and output data when they
5) No change in user space.

Other issues:

- save/restore support for live migration
- some way to limit the number of open handles (comes automatically with the table approach I suggested earlier)

error compiling committee.c: too many arguments to function

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at