While benchmarks are a very difficult exercice and as such the results must be considered carefully, they are still interesting to compare the respective performance between the solutions for different workloads.

This page will try to keep an eye on the relative performances of HVM Xen and KVM: the guest system is a "unmodified OS".

For the following 2 tests, the system is an Intel core 2 duo 2.4Ghz w/ 2GB RAM running the latest available versions:

 * for Xen: opensource Xen 3.1.0 + Dom0 kernel based on kernel.org 2.6.18
 * for KVM: kvm-60 on a 2.6.23

The guest used in both case is the exact same VM (non-paravirtualised 64 bit Debian etch with 256 MB RAM).

= Guest system boot-up time =

|| '''plateform'''||'''time in seconds'''||
|| '''Xen''' || 23 ||
|| '''KVM''' || 20 ||

= Kernel compilation benchmark =

Time to compile a  2.6.24 allnoconfig

 * first try - cold cache

|| '''plateform'''||'''real time'''||'''user time'''||'''sys time'''||
|| '''Xen''' || 1m53 || 1m06 || 0m43 ||
|| '''KVM''' || 1m03 || 1m06 || 0m33 ||

 * second try - w/ cache

|| '''plateform'''||'''real time'''||'''user time'''||'''sys time'''||
|| '''Xen''' || 1m52 || 1m07 || 0m43 ||
|| '''KVM''' || 0m56 || 1m07 || 0m31 ||