System effects of interprocessor communication latency in multicomputers

A series of experiments and analyses on five types of hypercube and grid-topology multicomputers, carried out to evaluate interprocessor communication performance, is described. The effects on the system of communication speed, message routing, interprocessor connectivity, and message-passing software/hardware protocols were studied. The experimental results clearly show the difference in interprocessor communication performance between the first-generation multicomputer systems and the second-generation distributed multiprocessor systems. The traditional store-and-forward technique for interprocessor communication greatly limits the communication speed among the processors. In addition, the processors of the first-generation systems are not very powerful, which is another major reason communication proceeds slowly in these systems. It is seen that the wormhole routing model greatly reduces communication latency and is not sensitive to the distance involved in passing messages.<>