Acta Numerica (2012), pp. 001– c Cambridge University Press, 2012 doi:10.1017/S09624929 Printed in the United Kingdom High Performance Computing Systems: Status and Outlook J.J. Dongarra University of Tennessee and Oak Ridge National Laboratory and University of Manchester
[email protected] A.J. van der Steen NCF/HPC Research L.J. Costerstraat 5 6827 AR Arnhem The Netherlands
[email protected] CONTENTS 1 Introduction 1 2 The main architectural classes 2 3 Shared-memory SIMD machines 6 4 Distributed-memory SIMD machines 8 5 Shared-memory MIMD machines 10 6 Distributed-memory MIMD machines 13 7 ccNUMA machines 17 8 Clusters 18 9 Processors 20 10 Computational accelerators 38 11 Networks 53 12 Recent Trends in High Performance Computing 59 13 HPC Challenges 72 References 91 1. Introduction High Performance computer systems can be regarded as the most power- ful and flexible research instruments today. They are employed to model phenomena in fields so various as climatology, quantum chemistry, compu- tational medicine, High-Energy Physics and many, many other areas. In 2 J.J. Dongarra & A.J. van der Steen this article we present some of the architectural properties and computer components that make up the present HPC computers and also give an out- look on the systems to come. For even though the speed of computers has increased tremendously over the years (often a doubling in speed every 2 or 3 years), the need for ever faster computers is still there and will not disappear in the forseeable future. Before going on to the descriptions of the machines themselves, it is use- ful to consider some mechanisms that are or have been used to increase the performance.