Sometimes your Mac might not run as quickly as you expect, and you’d like to know why. A good first stop that all Mac users should be aware of is Activity Monitor, located in /Applications/Utilities/. This program lets you see various statistics about what’s running on your Mac, as well as overall statistics like RAM, disk, and network usage. If you select a process, you can choose to sample it – for a short period the state of the program is periodically recorded, which helps developers figure out where a program is spending all its time.
If you’ve read A Beginner’s Guide to VMware Fusion, you know that Fusion really consists of two processes – a UI process called "VMware Fusion", which handles user input, and a backend process called vmware-vmx which does all the real work of virtualizing your guest. If you run multiple virtual machines, you’ll have a vmware-vmx for each guest but only one UI process. One catch is that vmware-vmx is root-owned, so if you want to see it in Activity Monitor, you need to select All Processes to be shown.
If you recall my previous post, we should try to think in layers. Activity Monitor only covers the host and Fusion layers, but things aren’t broken down beyond that. To see what’s going on inside the guest, we need guest-specific tools. A virtual computer is very similar to a physical computer, so we start with the same tools you would use on a real machine.
For Windows guests, a good next step is to check out Task Manager. You can get to Task Manager by Virtual Machine > Send Ctrl-Alt-Del. Note that unlike Activity Monitor, Task Manager has an entry for unused time, which falls under System Idle Process. In this example, I’ve just started Steam.
If you’re interested in this sort of thing, much more has been written on the subject by other people. This is just the very basics, intended to get you thinking about how to keep track of what’s going on in a virtual machine.