Communication Pre-evaluation in HPF

Pierre Boulet *   Xavier Redon #

Abstract: Parallel computers are difficult to program efficiently. We believe that a good way to help programmers write efficient programs is to provide them with tools that show them how their programs behave on a parallel computer. Data distribution is the major performance factor of data-parallel programs and so automatic data layout for High Performance Fortran programs has been studied by many researchers recently. The communication volume induced by a data distribution is a good estimator of the efficiency of this data distribution.

We present here a symbolic method to compute the communication volume generated by a given data distribution during the program writing phase (before compilation). We stay machine-independent to assure portability. Our goal is to help the programmer understand the data movements its program generates and thus find a good data distribution. Our method is based on parametric polyhedral computations. It can be applied to a large class of regular codes.

This document was translated from LATEX by HEVEA and HACHA.