kvm perf question

kvm perf question

[Xuekun Hu]

Hi, All

I started a VM, and nothing running in that VM. Then using “perf stat”
to collect some data, interesting thing is the number of “kvm_apic” is
greater than that of “kvm_exit”. My understanding is “kvm:kvm_exit” is
the number of vmexit, while “kvm_apic” is the number of vmexit due to
apic access. Is my understanding right? If so, in what condition the
number of “kvm_apic” could be greater than that of “kvm_exit”?

[root@centos_ivy ~]# perf stat -a -e 'kvm:kvm_exit' -e 'kvm:kvm_apic'
-e "kvm:kvm_apic_ipi" sleep 1s

Performance counter stats for 'sleep 1s':

           47,251 kvm:kvm_exit
        [100.00%]
           52,650 kvm:kvm_apic
        [100.00%]
            4,519 kvm:kvm_apic_ipi

      1.001805327 seconds time elapsed

My configuration is : ivybridge-EP, Centos, kernel 3.15.0.

Many thanks.

Thx, Xuekun