Importance of selecting data layouts in the tsunami simulation code

Exploiting the memory performance is one of the keys to accelerate the memory-intensive applications. A way for improving the memory performance is to make memory accesses efficient. Since the memory access pattern changes depending on data layouts, it is necessary for effective memory access to choose the appropriate data layout. This paper focuses on the tsunami simulation as one of the high performance computing applications that require the high memory performance. To examine the performance variance due to the data layouts, several data layouts are applied to the tsunami simulation. From the evaluation results, this paper clarifies that the performance of the tsunami simulation is sensitive to the input data, the computing systems, and the data layouts. The execution time of the tsunami simulation with an array of structures is much longer than those with a discrete array and a structure of arrays. The performances of the discrete array and the structure of arrays are not high in specific cases but changed according to the computing systems and the input data. Based on these observations, this paper indicates the importance of the data layout selection to exploit the memory performance.