Analysis and Optimization of Output Operations in the INM RAS Earth System Model

Abstract

The modern development of complex Earth system models forces developers to take into account not only the computational efficiency, but also the performance of the data input and output. This work evaluates the data output performance of the INM RAS Earth system model and optimizes its weak points. The output operations were found to be surprisingly slow on the Cray XC40-LC supercomputer compared to the results obtained on the INM RAS cluster. To identify the bottleneck, the computational time, the distributed data gathering time, and the file system output time were measured separately. The distributed data gathering time was the cause of the slowdown on the Cray XC40-LC, so optimizations were made to the gathering routines without any additional rework of the existing output code. The optimizations resulted in a significant reduction in the overall model running time on the Cray XC40-LC, while the gathering time itself was reduced by a factor of 10 2 -10 3 . The results highlight the importance of optimizing the output performance in Earth system models.