Experimental performance evaluation of the CM-5

In this paper, we present an extensive experimental performance evaluation of the communication capabilities of the CM-5. We first study the communication characteristics such as start-up time, sustainable bandwidth for simple messages as a function of message size and number of processors, and the effect of multiple messages and link contention on the communication time. We study the effect of dense communication patterns such as complete exchange and propose four algorithms for scheduling a complete exchange operation. We also consider the scheduling of irregular communication patterns and present four algorithms for the same. We have tested these algorithms on many synthetic irregular communication patterns as well as those arising in real problems such as the conjugate gradient solver and the Euler solver. Finally, we study the performance and communication aspects of scientific applications such as two-dimensional FFT and Gaussian Elimination on the CM-5.