VPP Fortran and the design of HPF/JA extensions

Abstract

SUMMARYVPP Fortran is a data parallel language that has been designed for the VPP series of supercomputers. In addition to pure data parallelism, it contains certain low-level features that were designed to extract high performance from user programs. A comparison of VPP Fortran and High-Performance Fortran (HPF) 2.0 shows that these low-level features are not available in HPF 2.0. The features include asynchronous interprocessor communication, explicit shadow, and the LOCAL directive. They were shown in VPP Fortran to be very useful in handling real-world applications, and they have been included in the HPF/JA extensions. They are described in the paper. The HPF/JA Language Specification Version 1.0 is an extension of HPF 2.0 to achieve practical performance for real-world applications and is a result of collaboration in the Japan Association for HPF (JAHPF). Some practical programming and tuning procedures with the HPF/JA Language Specification are described, using the NAS Parallel Benchmark BT as an example.

Towards a Lightweight HPF Compiler

“…This section estimates how the replacement of SPMD converter and RTS affects the peak performance of an HPF program for the high-end implementation. We have tuned the NAS Parallel BT benchmark code [18] on VPP5000 with HPF/JA language extensions and vector optimization [2]. In order to compare with this result, we estimated the performance of the generated code of the new compiler for high-end machines shown in Fig.…”

“…We have developed UXP/V HPF, the HPF compiler for VPP800 and VPP5000 [1] series vector-parallel computers [2]. This compiler offers valuable results, which include the world record of performance in HPF applications [3].…”