From Fedora Project Wiki


Enable PV EOI enhancement for a VM, and verify it cuts down on VM exits (and hence improves performance).


Nothing beyond the initial test day setup (basically a function F18 VM).

How to test

  1. Start a guest. It should be the only guest running. Connect to the graphical console with virt-manager, log in and open a terminal
  2. Inside the guest, do ping
  3. Back on the host machine, yum install -y perf
  4. Run the following perf command as root
    perf stat --event "kvm:*" --all-cpus sleep 10
  5. Notice the values for kvm_entry/kvm_exit (mine were around 110,000)
  6. Shutdown the guest
  7. Enable PV EOI
    1. # virsh edit f18
    2. Check <apic/> to <apic eoi="on"/>
    3. Save and exit
  8. Start the guest, connect with virt-manager, and restart the ping command
  9. Run the perf command again on the host
  10. View reduced entry/exit count (mine was around 30,000, over 70% reduction)

Expected Results

No obvious errors occur, entry/exit are reduced by a noticeable amount.