The Parallel Runtime

Message Passing

•Message passing is provided by a machine-specific library, but there are standard APIs

–MPI -- Message passing interface

–PVM -- Parallel Virtual Machine

•Example operations

•Blocking send … send msg, wait until it is acked

•Non-blocking send … send msg, continue execution

•Wait_for_ACK … wait for ack of non-blocking send

•Receive … get msg that has arrived

•Programmers insert the library calls in-line in C or Fortran programs