What is Atomic instruction?

Atomic instruction in the explanations

• An atomic instruction performs a read, compute and write sequence such that no other core's access can come in between.

  Which describes an atomic instruction?

• An atomic instruction involves a write, so waiting threads that keep executing it fight to own the line in the M state and keep invalidating others' copies.

  Why does a spinlock usually wait with ordinary reads and us…

• A spinlock tries to acquire the lock with an atomic instruction and, if that fails, immediately tries again, over and over.

  Which describes a spinlock?

Questions that mention Atomic instruction (3)

1. Which describes an atomic instruction?
2. Why does a spinlock usually wait with ordinary reads and use an atomic instruction only when the lock looks free (test-and-test-and-set), instead of retrying the atomic write directly?
3. Which describes a spinlock?

Related terms

Spinlock Compare-and-swap Load-reserved/store-conditional (LR/SC) Interrupt ABA problem Acquire-release semantics Barrier synchronization Bus snooping Condition variable Critical section