Question

Question as stated above .. from the stand point of Operating System, which one is easier to create, a thread or a process?

Answer 1

A new thread should be faster to create than a new process.

A process is a heavy weight system structure. It has it’s own virtual memory space, owns all handles (mutexes, semaphores, open files), and has protection from other processes. Cross-process communication has to go through the OS.

A thread is a “child” to a process. A thread is simply an execution context (registers, stack, and thread-local state) that can run on another hardware core or be co-scheduled on the same core as other threads within a process. Multiple threads share the resources of a single process including the address space and OS handles owned by the process.

There are structures even faster than dynamically creating threads for achieving multitasking during a programs runtime.

Some systems or code libraries support have thread pools (light-weight threads). In this case, you tell the system how many threads you want to run and it creates them up front. Then instead of creating and destroying threads (which is still a relatively slow process), you can allocate and free threads from this pool.

Job Tasking is another similar lighter weight multicore structure where you have several threads with a job queues of tasks to execute. They run the tasks in their job queues and then sleep when the queues are empty.

For both thread pools and job tasking, there is no need for thread startup / shutdown cost aside from upon creation and destruction of the global pools and queues.