Ddt: a Research Tool for Automatic Data Distribution in Hpf

This paper describes the features and implementation of our automatic data distribution research tool. The tool (DDT) accepts programs written in Fortran77 and generates HPF directives and executable statements. DDT works by identifying a set of computational phases (procedures and loops). The algorithm builds a search space of candidate solutions for these phases which is explored looking for their combination that minimize the overall cost; this cost includes movement cost and computation cost. The data movement cost includes the cost of executing each phase with a given mapping and the remapping costs that have to be paid in order to execute each phase with the mapping selected. The computation cost includes the cost of executing each phase in parallel according to the mapping selected and the owner computes rule. Control ow information is used to identify how phases are sequenced during the execution of the application.