Compiler optimizations for red-black HPF codes

Abstract

A case study is presented of the compiler optimizations that have been used to generate efficient code for a red-black relaxation problem coded in HPF and targeted at distributed memory. High Performance Fortran (HPF) gives the programmer the ability to express the parallelism at a high level without entering into the low-level details of message-passing and synchronization thereby reducing the time and effort required for parallel program development. Because the HPF compiler is responsible for scheduling the parallel operations on the physical machines, HPF opens up a vast area of optimizations which the compiler must perform in order to generate efficient code. These are optimizations which would otherwise have been performed by the programmer at a lower level (using explicit message passing). Some timings from the Digital Fortran 90 compiler showing the effect of these optimizations are presented.