How do I spawn threads on different CPU cores?

Question

Let\'s say I had a program in C# that did something computationally expensive, like encoding a list of WAV files into MP3s. Ordinarily I would encode the files one at a time

Answer 1

In the case of managed threads, the complexity of doing this is a degree greater than that of native threads. This is because CLR threads are not directly tied to a native OS thread. In other words, the CLR can switch a managed thread from native thread to native thread as it sees fit. The function Thread.BeginThreadAffinity is provided to place a managed thread in lock-step with a native OS thread. At that point, you could experiment with using native API's to give the underlying native thread processor affinity. As everyone suggests here, this isn't a very good idea. In fact there is documentation suggesting that threads can receive less processing time if they are restricted to a single processor or core.

You can also explore the System.Diagnostics.Process class. There you can find a function to enumerate a process' threads as a collection of ProcessThread objects. This class has methods to set ProcessorAffinity or even set a preferred processor -- not sure what that is.

Disclaimer: I've experienced a similar problem where I thought the CPU(s) were under utilized and researched a lot of this stuff; however, based on all that I read, it appeared that is wasn't a very good idea, as evidenced by the comments posted here as well. However, it's still interesting and a learning experience to experiment.