Last year, Richard explained  why sampling does not work on Virtual PC.   Since the sampling failure is quite catastrophic, we blocked all profiling on Virtual PC.

Some Beta users noticed that we block profiling also for instrumentation-based profiling. If you are one of these people, I have good news and bad news for you.

The good news is that we will enable profiling instrumented applications on a Virtual PC. [Disclaimer: I am writing here about a product that is not yet released so this is not final]

The bad new is that this may not be a good idea to do that. The performance characteristics on a virtual machine can be different from a real machine. For example, I/O on a virtual machine takes longer as it virtualized. Virtual PC emulates a single, non-hyper threaded CPU. If your application is going to be deployed on a multi-processor server, you’d better profile on such environment and not on a single-CPU machine.