Communication Performance of Gigabit LAN Workstation Cluster RWC/WSC

Using workstation clusters (WSCs) is a practical and cost-e ective means of parallel computing. Fast workstations, using the latest RISC technology, can be assigned as computation nodes, however, communication between nodes is rather slow when using Ethernet. Recently, fast communication adaptors[2] have been developed, and the speed problem is being solved. We have developed a WSC called the RWC/WSC. It consists of 36 nodes (SparcStation 20) connected by Myrinet. To use Myrinet e ciently, a communication library (PM) which can achieve a low latency and a high bandwidth has been designed. This paper reports on the communication performance of the RWC/WSC. It is then compared with massively parallel machines: the CM5 and the Paragon. For comparison, speci c collective communications primitives[4] such as broadcast and reduction are used, because they are commonly used in parallel programs, and are convenient for evaluating the performance of parallel systems. CG-kernel benchmark from NAS parallel benchmarks is also used to compare the RWC/WSC with the Paragon. The next section introduces the Myrinet, PM and the RWC/WSC brie y. In the third section, the performance of collective communications and the benchmark program of the RWC/WSC is compared with the CM-5 and the Paragon. We found that the performance of our PM is comparable to the MPP's in a 32 processor system.