What are the differences between mutex and spinlock?

What are the differences between mutex and spinlock?

Mutex and spinlock are both synchronization primitives used in concurrent programming. A mutex allows only one thread to access a resource at a time, putting other threads to sleep until the mutex is released. In contrast, a spinlock keeps checking the lock in a loop (spinning) until it becomes available, which can be more efficient for short wait times but can waste CPU cycles.

When should I use a mutex instead of a spinlock?

You should use a mutex when you expect threads to be blocked for a longer time, as it puts them to sleep, conserving CPU resources. Use a spinlock for short critical sections where the wait time is minimal, as it can be faster due to less overhead.

Are there any downsides to using spinlocks?

Yes, spinlocks can lead to wasted CPU cycles if the wait time is long, as they keep the CPU busy checking the lock. This can degrade performance, especially in a multi-core system where other threads could be executing.

Can you give an example of when to use each?

Sure! Use a mutex for file access where the operation might take time, like reading or writing large files. Use a spinlock for a quick operation, like incrementing a counter, where the lock is held for a very short duration.