Multithreading: What is the point of more threads than cores?

Question

I thought the point of a multi-core computer is that it could run multiple threads simultaneously. In that case, if you have a quad-core machine, what\'s the point of having

Answer 1

The point is that the vast majority of programmers do not understand how to design a state machine. Being able to put everything in its own thread frees the programmer from having to think about how to efficiently represent the state of different in-progress computations so that they can be interrupted and later resumed.

As an example, consider video compression, a very cpu-intensive task. If you're using a gui tool, you probably want the interface to remain responsive (show progress, respond to cancel requests, window resizing, etc.). So you design your encoder software to process a large unit (one or more frames) at a time and run it in its own thread, separate from the UI.

Of course once you realize it would have been nice to be able to save the in-progress encoding state so you can close the program to reboot or play a resource-hungry game, you realize you should have learned how to design state machines from the beginning. Either that, or you decide to engineer a whole new problem of process-hibernation your OS so you can suspend and resume individual apps to disk...