The Parallel Communication and I/O Bandwidth Benchmarks: b eff and b eff io

We describe the design and MPI implementation of two benchmarks created to characterize the balanced system performance of high-performance clusters and supercomputers. We start with a communication-specific benchmark, called b eff that characterizes the message passing performance of a system. Following the same line of development, we extend this work to the design and implementation of the effective I/O bandwidth benchmark (beff io). Both of these benchmarks were developed on a Cray T3E-900 and have two goals: a) to get a detailed insight into the performance strengths and weaknesses of different parallel communication and I/O patterns, and b) to obtain a single bandwidth number that characterizes the average performance of the system namely processor communication for beff, and the I/O subsystem for b eff io. Both benchmarks use a timedriven approach and loop over a variety of communication and access patterns to characterize a system in a fairly automated fashion. Results of the two benchmarks are given for several systems including IBM SPs, Cray T3E, NEC SX5, and Hitachi SR 8000.