Performance of the direct binary n-cube network for multiprocessors

A mathematical model for predicting the performance of the direct binary n-cube interconnection scheme is presented. These predictions are checked against simulations of a comparable system. The results for the network are compared to known results for indirect interconnection schemes like the crossbar and indirect n-cube networks. Special operation conditions such as broadcasts and hot spots are considered. The following main inferences can be drawn from the study. Indirect networks need to use switches of size significantly larger than 2×2 to equal or better the performance of the hypercube system, under equiprobable distribution of message destinations. Sources attached to nodes in the direct network must be capable of generating multiple messages in a cycle to exploit the available bandwidth fully which is a key difference from the indirect networks. A variant of the standard broadcast algorithm introduced achieves a balanced distribution of network traffic, permitting the hypercube to support significant amounts of broadcast messages. These studies indicate that the transient effects of potential hot spot nodes on the background messages are small in the case of the hypercube