Evaluation of the computational performance of the finite-volume atmospheric model of the IAP/LASG (FAMIL) on a high-performance computer

Abstract

High computational performance is extremely important for climate system models, especially in ultra-high-resolution model development. In this study, the computational performance of the Finite-volume Atmospheric Model of the IAP/LASG (FAMIL) was comprehensively evaluated on Tianhe-2, which was the world’s top-ranked supercomputer from June 2013 to May 2016. The standardized Atmospheric Model Inter-comparison Project (AMIP) type of experiment was carried out that focused on the computational performance of each node as well as the simulation year per day (SYPD), the running cost speedup, and the scalability of the FAMIL. The results indicated that (1) based on five indexes (CPU usage, percentage of CPU kernel mode that occupies CPU time and of message passing waiting time (CPU_SW), code vectorization (VEC), average of Gflops (Gflops_AVE), and peak of Gflops (Gflops_PK)), FAMIL shows excellent computational performance on every Tianhe-2 computing node; (2) considering SYPD and the cost speedup of FAMIL systematically, the optimal Message Passing Interface (MPI) numbers of processors (MNPs) choice appears when FAMIL use 384 and 1536 MNPs for C96 (100 km) and C384 (25 km), respectively; and (3) FAMIL shows positive scalability with increased threads to drive the model. Considering the fast network speed and acceleration card in the MIC architecture on Tianhe-2, there is still significant room to improve the computational performance of FAMIL.

Keywords

• FAMIL
• scalability
• computational performance
• Tianhe-2