If a point-to-point message-passing routine is called repeatedly with the same arguments, persistent communication can be used to avoid redundancy in setting up the message each time it is sent. Persistent communication reduces the overhead of communication between the parallel task and the network adapter, but not the overhead between network adapters on different nodes.

One class of program that is appropriate for persistent communication is data decomposition problems in which points are updated based on the values of neighboring points. In this case, for many iterations, tasks send points that border their neighbor's domain, and receive points that border theirs. At each iteration, the location, amount, and type of message data, the destination or source task, and the communicator stay the same. The same message tags can be used, because persistent communication requires the communication to be completed within each loop iteration.

Persistent communication is non-blocking. You can choose to have both sides of the communication use persistent communication, or only one side.