3 ms·

Thanks, why do you need to spin if there is no contention for the lock though? That sounds counterintuitive.

• slrz 9y ago
  Well, you don't. Just like when acquiring an unlocked spinlock. ;-) Should look something like this: for(;;){ if(atomic_swap(&thefutex, 1) == 0) break; // we own the lock now // slow path, go to sleep until awoken syscall(SYS_FUTEX, FUTEX_WAIT, ...); }