Ok, so I am reading about synchronization, and I read through various algorithms such as spinlocks, semaphores, and mutex to avoid race condition.
However, these algorithms can't prevent race condition in SMP when multiple proceses access the data exactly at the same time.
For example, suppose thread 1 in processor A runs lock(mutex1); withdraw(1000); unlock(mutex1);
and thread 2 in processor B runs lock(mutex1); deposit(1000); deposit(1000); unlock(mutex1);
When both threads run EXACTLY AT THE SAME TIME, both threads will be in critical section simultaneously.
The only solution (should be in hardware level) would be making each processors run slightly off to each other, but it defeats the purpose of parallelism.
Is there any hardware level support to avoid these situation where multiple processors try to acquire the lock at the exactly same time?
(this is not a problem of atomicity, but rather problem of exact parallelism, and I wonder how SMP deals with it).
