Author: Johan De Gelas Page 1 Introduction First dual-core in 2005, then quad-core in 2007: the multi-core snowball is rolling. The desktop market is still trying to find out how to wield all this power; meanwhile, the server market is eagerly awaiting the octal-cores in 2009. The difference is that the server market has a real killer application, hungry for all that CPU power: virtualization. While a lot has been written about the opportunities that virtualization brings (consolidation, hosting legacy applications, resource balancing, faster provisioning...), most publications about virtualization are rather vague about the "nuts and bolts". We talked to several hypervisor architects at VMWorld 2008. In this article, we'll delve a bit deeper as we look to understand the impact of virtualization on performance. Performance? Isn't that a non-issue? Modern virtualization solutions surely do not lose more than a few percent in performance, right? We'l