What are spinlocks?

What are spinlocks and how do they work?

Spinlocks are synchronization primitives used in concurrent programming to protect shared resources. They work by repeatedly checking if a lock is available and 'spinning' in a loop until it is.

When should I use spinlocks instead of other locking mechanisms?

Spinlocks are best used in scenarios where the wait time is expected to be very short, as they can be more efficient than traditional locks in such cases.

What are the downsides of using spinlocks?

The main downsides include wasting CPU cycles while waiting and potential priority inversion issues, which can affect system performance.

Can you give me an example of spinlock implementation?

Sure! Here's a simple example in C:

typedef struct {
    volatile int lock;
} spinlock;

void spinlock_init(spinlock *s) {
    s->lock = 0;
}

void spinlock_lock(spinlock *s) {
    while (__sync_lock_test_and_set(&s->lock, 1)) {
        while (s->lock);
    }
}

void spinlock_unlock(spinlock *s) {
    __sync_lock_release(&s->lock);
}