Efficient Personalized Communication on Wormhole Networks

Bridging models, as the BSP, tend to abstract the characteristics of the interconnection networks using a small set of parameters, by dividing the computation in supersteps and organizing the communication in global patterns called h-relations. In this paper we evaluate, through experimental results conducted on a wormhole-routed bi-dimensional torus and a quaternary fat-tree with 256 processing nodes, the execution time of three families of h-relations with variable degree of imbalance. We also prove a strong result that links the communication performance of the fat-tree with the BSP abstraction of the interconnection network. Given a generic h-relation, we can provide a value of g that, in the worst case, slightly overestimates the completion time and is very close to optimality