A communication scheme for the distributed execution of loop nests withwhile loops

Abstract

The mathematical model for the parallelization, or “space-time mapping,” of loop nests is the polyhedron model. The presence ofwhile loops in the nest complicates matters for two reasons: (1) the parallelized loop nest does not correspond to a polyhedron but instead to a subset that resembles a (multidimensional) comb and (2) it is not clear when the entire loop nest has terminated. We describe a communication scheme which can deal with both problems and which can be added to the parallel target loop nest by a compiler.