What is a Thread-pool?

Question

What is the concept of implementing Thread-pool (in C with help from pthreads)? how can a thread be assigned to execute from the thread pool ?

Answer 1

A thread-pool is a collection of a fixed number of threads which are created on application startup. The threads then sit waiting for requests to come to them, typically via a queue controlled by a semaphore. When a request is made, and there is at least one thread waiting, the thread is woken up, services the request, and goes back to waiting on the semaphore. If no threads are available, requests queue up until one is.

Thread-pools are a generally more efficient way of managing resources than simply starting a new thread for every request. However, some architectures allow new threads to be created and added to the pool as the application runs, depending on request loading.