Question

I have a block of code that needs to run fast, right now I’m using pthread_mutex_lock/pthread_mutex_unlock to sync the threads but I saw that it has a certain impact on performance. I was wondering, if anyone ever benchmarked this, is sem_post/sem_wait significantly faster than pthread_mutex_lock/pthread_mutex_unlock?

Thanks!

Answer 1

I’d say a semaphore is probably slower than a mutex because a semaphore has a superset of the mutex behavior. You can try something at user level such as spin lock that runs without kernel support, but it all depends on the rate of lock/unlocks and the contention.