What are the differences between mutex and spinlock in C++?

What are the differences between mutex and spinlock in C++?

Mutex and spinlock are both synchronization primitives used in C++. A mutex allows only one thread to access a resource at a time, blocking other threads until it's released. Spinlock, on the other hand, keeps checking (or 'spinning') until the lock is 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 longer wait times, as it puts the thread to sleep, freeing up CPU resources. Use a spinlock for short critical sections where the wait time is minimal, as it can be faster in those cases.

Are there any performance considerations I should be aware of?

Yes, performance can vary based on the use case. Mutexes can introduce context switching overhead, while spinlocks can lead to CPU contention if many threads are waiting. It's essential to analyze your specific scenario to choose the right one.

Can you give an example of when to use each?

Sure! Use a mutex for protecting access to a shared resource like a file or database connection. Use a spinlock for protecting a small, frequently accessed variable where the wait time is expected to be very short.