On the Performance of the Shallow Water Model on Distributed Memory Architectures

Abstract

This paper, is a study of the impact of memory architectures, distributed memory (DM) and virtual shared memory (VSM), in the solution of parallel numerical algorithms on a multi-processor cluster. A parallel implementation of the shallow water equations to model a Tsunami is chosen as the case study. Data are partitioned into sub-domains, namely a four by three (4X3) Grid scheme and an eight by six (8X6) Grid scheme which are used for the parallel implementation of this model. There are four versions of the parallel algorithm for each Grid scheme: distributed memory without threads, distributed memory with threads, virtual shared memory without threads, and virtual shared memory with threads. These four parallel versions have been implemented on a high performance cluster, connected to the "Nordugrid". Experiments are realized using the Message Passing Interface (MPI) library, the C/Linda, and the Linux pthreads. Subject to the availability of memory, the virtual shared memory version without threads performs best, and as the task is scaled up, the threaded version becomes efficient in both DM and VSM implementations.