An examination of the conversion of software to multiprocessors

Abstract This paper examines the process of and problems involved in converting an application to make use of parallel processor machines. We mapped a Fortran software package for solving ordinary differential equations using the Cray multitasking primitives onto a Cray X-MP/48 supercomputer. An interesting aspect of this study is the conversion of a library rather than stand-alone code, and we must deal with uncertainties from the calling routines. Two conversions are performed: the first allows multiple problems to execute concurrently, and the second exploits parallelism within each individual problem. The issues involved in each of these conversions are presented with the solutions considered. Performance measurements are presented for each conversion performed.