Donald Bren School of Information and Computer Sciences

We introduce a technique for lowering the communication cost in a certain type of distributed application, in which processors perform computation in each time step and must obtain boundary data from their neighbors before they can perform the next time step. A typical example of such an application is solving differential equations using the finite difference method. Our method, which we call SuperBoundary Exchange, consists of sending a larger boundary less often. This results in less frequent data exchange, trading off against larger messages and some redundant computation. We present experimental data showing that our method consistently results in significant speedup in communication-intensive applications, under varying assumption about the balance of computation load among the processors.