VPP Fortran and the design of HPF/JA extensions

VPP 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 HPF 2.0 shows that these low-level features are not available in HPF 2.0. The features include asynchronous inter-processor 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 speci cation 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 speci cation are described, using the NAS Parallel Benchmark BT as an example.