Optimizing irregular HPF applications using halos
Siegfried Benkner · Concurrency Practice and Experience · 2000
This paper presents extensions of High Performance Fortran (HPF) for specifying non-local access patterns of distributed arrays, called halos, and for controlling communication associated with these non-local accesses. Using these features, crucial optimization techniques required for an efficient parallelization of irregular applications may be applied. The information provided by halos is utilized by the compiler and the runtime system for optimizing the management of distributed arrays and the computation of communication schedules. High-level communication primitives for halos enable the programmer to avoid redundant communication, to reuse communication schedules, and to hide communication overheads by overlapping communication with computation. Performance results of a kernel from a crash simulation application on the NEC Cenju-4, the IBM SP2, and on the NEC SX-4 demonstrate that by using the proposed extensions, a performance close to handwritten message-passing codes can be achieved for irregular problems. Copyright © 2000 John Wiley & Sons, Ltd.