Kohichiro Hotta

Hybrid parallel programming on SMP clusters using XPFortran and OpenMP

Process-thread hybrid programming paradigm is commonly employed in SMP clusters. XPFortran, a parallel programming language that specifies a set of compiler directives and library routines, can be used to realize process-level parallelism in distributed memory systems. In this paper, we introduce hybrid parallel programming by XPFortran to SMP clusters, in which thread-level parallelism is realized by OpenMP. We present the language support and compiler implementation of OpenMP directives in XPFortran, and show some of our experiences in XPFortran-OpenMP hybrid programming. For nested loops parallelized by process-thread hybrid programming, it’s common sense to use process parallelization for outer loops and thread parallelization for inner ones. However, we have found that in some cases it’s possible to write XPFortran-OpenMP hybrid program in a reverse way, i.e., OpenMP outside, XPFortran inside. Our evaluation results show that this programming style sometimes delivers better performance than the traditional one. We therefore recommend using the hybrid parallelization flexibly.

Towards a Lightweight HPF Compiler

The UXP/V HPF compiler, that has been developed for the VPP series vector-parallel supercomputers, extracts the highest performance from the hardware. However, it is getting difficult for developers to concentrate on a specific hardware. This paper describes a method of developing an HPF compiler for multiple platforms without losing performance. Advantage is taken of existing technology. The code generator and runtime system of VPP Fortran are reused for high-end computers; MPI is employed for general distributed environments, such as a PC cluster. Following a performance estimation on different systems, we discuss effectiveness of the method and open issues.

On the Implementation of OpenMP 2.0 Extensions in the Fujitsu PRIMEPOWER Compiler

The OpenMP Architecture Review Board has released version 2.0 of the OpenMP Fortran language specification in November 2000, and version 2.0 of the OpenMP C/C++ language specification in March 2002. This paper discusses the implementation of the OpenMP Fortran 2.0 WORKSHARE construct, NUM_THREADS clause, COPYPRIVATE clause, and array REDUCTION clause in the Parallelnavi software package. We focus on the WORKSHARE construct and discuss how we attain parallelization with loop fusion.