Bulk Synchronous Parallel Computing - A Paradigm for Transportable Software

Abstract

A necessary condition for the establishment, on a substantial basis, of a parallel software industry would appear to be the availability of technology for generating transportable software, i.e. architecture independent software which delivers scalable performance for a wide variety of applications on a wide range of multiprocessor computers. This paper describes H-BSP - a general purpose parallel computing environment for developing transportable algorithms. H-BSP is based on the Bulk Synchronous Parallel Model (BSP), in which a computation involves a number of supersteps, each having several parallel computational threads that synchronize at the end of the superstep. The BSP Model deals explicitly with the notion of communication among computational threads and introduces parameters g and L that quantify the ratio of communication throughput to computation throughput, and the synchronization period, respectively. These two parameters, together with the number of processors and the problem size, are used to quantify the performance and, therefore, the transportability of given classes of algorithms across machines having different values for these parameters. This paper describes the role of unbundled compiler technology in facilitating the development of such a parallel computer environment.