- A barrier is an instruction given to the CPU or a compiler that requires that tasks performed in the computer memory are executed in the proper order (specified by the programmer). For example, this can avoid issues in computers with more than one CPU where memory instructions could be received by one or more of the processors in a different order than they were originally intended. The memory barrier instruction prevents this by ensuring that a particular order is maintained for each CPU.
- A method used for synchronization in parallel computing that keeps a particular number of threads from running any further until the barrier is reached by one or more specified threads.
Also see: Memory definitions