C++ mutex locking thread priority

Question

I'm looking to give priority to a thread so that if two threads are waiting for a mutex, the thread with the highest priority will always take the mutex before the lower priority one.

A colleague suggested that by changing the thread priority of my thread I should achieve that. I tried using the SetThreadPriority() function to set one of the waiting threads to 0(normal) and the other one to 2 (highest) but it doesn't affect the mutex behavior like I was hoping. The lock currently always goes to the first thread that requested the ownership.

So is this behavior normal? Contrary to what my colleague thought? Is there a different way to give thread priority that I might be missing? Or am I looking at a more complicated problem to solve?

Answer 1

Thread priority says how much time the thread gets on the CPU as determined by the scheduler, which will preferentially schedule higher priority threads - it doesn't affect the behaviour of mutexes, and I'm not aware of any means of making it do so.