Designing Interconnection Networks for Multi-level Packaging

A central problem in building large scale parallel machines is the design of the interconnection network. Interconnectionnetwork design is largely constrained by packaging technology. We start with a generic set of packagingrestrictions and evaluate different network organizations under a random traffic model. Our results indicate thatcustomizing the network topology to the packaging constraints is useful. Some of the general principles that ariseout of this study are: 1) Making the networks denser at the lower levels of the packaging hierarchy has a significantpositive impact on global communication performance, 2) It is better to organize a fixed amount of communicationbandwidth as a smaller number of high bandwidth channels, 3) Providing the processors with the ability to toleratelatencies (by using multithreading) is very useful in improving performance