Evaluating the Hyperbolic Model on a Variety of Architectures

We illustrate the application of the hyperbolic model, which generalizes standard two-parameter dedicated-link models for communication costs in messagepassing environments, to four rather different distributed-memory architectures: Ethernet NOW, FDDI NOW, IBM SP2, and Intel Paragon. We first evaluate the parameters of the model from simple communication patterns. Then overall communication time estimates, which compare favorably with experimental measurements, are deduced for the message traffic in a scientific application code. For transformational computing on dedicated systems, for which message traffic is describable in terms of a finite number of regular patterns, the model offers a good compromise between the competing objectives of flexibility, tractability, and reliability of prediction. 1This author's work was supported in part by NSF grant ECS-9527169, and by NASA contract NAS119480 while the author was in residence at the Institute for Computer Applications in Science and Engineering (ICASE),NASA Langley Research Center, Hampton, VA 23681-0001.