AUTOMATIC CODE GENERATION OF OVERLAPPED COMMUNICATIONS IN A PARALLELIZATION TOOL

This paper addresses the exploitation of overlapping communication wit h calculation within parallel FORTRAN 77 codes for computational fluid dynamics (CFD) and computational structured dynamics (CSD). The obvio us objective is to overlap interprocessor communication with calculati on on each processor in a distributed memory parallel system and so im prove the efficiency of the parallel implementation. A general strateg y for converting synchronous to overlapped communication is presented together with tools to enable its automatic implementation in FORTRAN 77 codes. This strategy is then implemented within the parallelisation toolkit, CAPTools, to facilitate the automatic generation of parallel code with overlapped communications. The success of these tools are d emonstrated on two codes from the NAS-PAR and PERFECT benchmark suites . In each case, the tools produce parallel code with overlapped commun ications which is as good as that which could be generated manually. T he parallel performance of the codes also improve in line with expecta tion. (C) 1997 Elsevier Science B.V.