STEP: A Distributed OpenMP for Coarse-Grain Parallelism Tool

Abstract. To benefit from distributed architectures, many applications need a coarse grain paral-lelisation of their programs. In order to help a non-expert parallel programmer to take advantage of this possibility, we have carried out a tool called STEP (Système de Transformation pour l’Exécution Parallèle). From a code decorated with OpenMP directives, this source-to-source transformation tool produces another code based on the message-passing programming model automatically. Thus, the programs of the legacy application can easily and reliably evolve without the burden of re-structuring the code so as to insert calls to message passing API primitives. This tool deals with difficulties inherent in coarse grain parallelisation such as inter-procedural analyses and irregular code.