A Comparison of MPI and OpenMP Implementations of a Finite Element Analysis Code

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Table of Contents

A Comparison of MPI and OpenMP Implementations of a Finite Element Analysis Code

Authors

Acknowledgements

Overview

Contents

Introduction

The Problems

Element-by-Element Approach

CERN Tunnels

The Codes

Fortran 90 for PCG

Element Level Approach

System Used

System Used

Reproducible Timings?

Implementation with MPI

Parallelism in Code

Data Distribution

MPI Results

MPI results

Implementation with OpenMP

OpenMP

Compiler Options of particular interest

Using BLAS Routines

Matrix Multiplication Section

Matrix Multiplication

Dgemm versus OpenMP

Data placement - note

Gather — no problem

scatter

Parallelising scatter

Other parts of the code

OpenMP Results

OpenMP — comments

Comparison between MPI and OpenMP Implementations

Performance

Unfair Comparison?

For MPI

For OpenMP

Conclusions

Conclusions

Author: Michael Bane

Presenter: Terry Hewitt