A Comparative Study of the ECMWF Weather Model on Several Multiprocessor Architectures

Abstract

The European Centre for Medium-Range Weather Forecasts (ECMWF) first begun using multiprocessors in the early 1980s for the production of their weather service products. In the past few years, with the increasing number of and variety of multiprocessor systems on the market, it has become necessary to broaden the evaluation of multiprocessing. Toward this end, ECMWF has developed a suite of four benchmarks for the evaluation of multiprocessing. It should be noted that this benchmark suite is strictly for the evaluation of multiprocessing and is not in itself a complete benchmark suite. Every effort was made to allow for the study of multiprocessing and not raw performance. As a result, this study focuses on the efficiency of the multiprocessing systems available. Of the machines available on the market, only four were chosen for detailed study, partially because of their performance characteristics and partially because of the availability of hardware. The study will focus on the Cray X/MP 4-processor system, the ETA 10 (only simulations were performed), the IBM 3090/400 with vector facility, and the Floating Point Systems T series. The four benchmarks developed at ECMWF are MANDEL, MATRIX, SPEC and MODEL. Each of these is described below in terms of their structure and what aspect of multiprocessing they address.