A Communication Model for Optimizing Hierarchical Multiprocessor Systems

Experimental hierarchial multiprocessor systems have been built, notably the Cm* and the EGPA machine and the construction of the Cedar is in progress. As an examination of these three systems shows, hierarchical systems encompass a range of processor configurations and interprocessor communication links. The development of cost and performance models together with a knowledge of the eventual workload enables us to choose an appropriate processor configuration. This in turn permits us to examine the suitability of particular systems for solving problems with different patterns of interprocessor communication and to emulate other multiprocessor interconnection schemes. Since our primary objective is to compare various processor configurations in large systems, the models we have developed ignore factors which tend to have a similar effect on a wide range of configurations.