Re: How to measure VM events using perf-event

[Christopher Covington <cov@codeaurora.org>]

Hi Jueyuan,

On 04/09/2015 11:46 PM, Jueyuan Zhu wrote:
> Hello,
> 
> I am trying to use the perf-event to measure the events for one specified
> VM in KVM platform. Since each VM is just a process in the host OS, so I thought
> we could just set the process id of this VM in the perf-event_open API to
> count the events. The following is my code (based on the example from
> perf_event_open linux manual). 

> However, this program’s output keeps constant whenever this VM is idle, or
> running different benchmarks. So it seems the event counting is incorrect. Can
> anyone tell me how to set the flags or perf_event_attr to correctly count the
> VM events using perf_event_open? 

You may want to check that the QEMU or kvmtool you're using correctly
virtualizes or emulates the PMU for your architecture. Information about this
might be in the documentation or release notes or if not you could try asking
on the QEMU or kvmtool mailing list tool.

Chris

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