Disruptor

Concurrent execution of code is about two thing:

• mutual exclusion
• visibility of change

• A CAS operation is a special machine-code instruction that allows a word in memory to be conditionally set as an atomic.
• This CAS approach is significantly more efficient than locks because it does not require a context switch to the kernel for arbitration.
• However CAS operations are not free of cost. The processor must lock its instruction pipeline to ensure atomicity and employ a memory barrier to make the changes visible to other threads.