How to collect VM exit numbers in KVM

Sometimes, we may want to know the specific benchmark can cause what kind of VM exits.

1, Install perf.

2, # perf kvm stat record -a
^C

3, # perf kvm stat report

This will report your VM exit numbers and what kind of operation lead to VM exit. You may need to compare many times to see whether the workload will let your system produce different number of VM exit.