VirtualBox 3.0 is released!
By Fat Bloke on Jun 30, 2009
Good news! VirtualBox 3.0 is released. This is the release where guests went SMP (multiple vCPUs). And to show what that means here's a screenshot of a MacBook Pro (Intel Core 2 Duo) running:
- Windows Server 2008 with 4 vCPUs (left hand side);
- Ubuntu Server with 2 vCPUs (right hand side);
...on a host which has 2 physical CPUs, as can be seen from the Mac's Activity Monitor window bottom of picture. (Click on the image to zoom in).
For the interested amongst you, each virtual machine is a separate process on the host. And each process consists of several threads, where some of those host threads represent virtual CPUs, and others represent helper threads that deal with stuff like device access.
Configuring your guest for SMP is a piece of cake. The VirtualBox 3.0 UI has been modified to hopefully be easier to use and we've introduced a simple slider control to determine how many vCPUs you want to assign to your guest.
One point to note is that if you assign many more vCPUs than you have physical CPUs the system may run slower because the host spends more time scheduling threads than actually running them. So VirtualBox limits the CPUs you can assign to a guest to twice the number of physical CPUs. i.e. in the example above, 4 vCPUs was the limit of a 2 CPU system in a single guest (you can have several concurrent guests BTW). And on larger server platforms VirtualBox can go to a maximum of 32.