CPSA: A Coordinated Process Scheduling Algorithm for Coupled Earth System Model

Coupled climate system models are important tools for climatologists to predict and understand future climate. These models are usually resource-consuming due to the large number of processors required and long execution time. Although the performance and scalability of individual physical system model have been improved over the past years, coupled climate systems still suffer from low efficiency when sharing resource across models. This paper focuses on the process scheduling strategy of Coupled Earth System Model (CESM), a widely applied coupled system model. Instead of pursuing best speedup efficiency for individual component, the proposed resource allocation strategy allows components to execute on compromised sub-optimal setup and still maintains relatively high parallel speedup. With this flexible resource allocation strategy, we further propose a Coordinated Process Scheduling Algorithm (CPSA) to make efficient resource sharing configurations, including resource allocation and process layout of components. We integrate CPSA as a tool into CESM program, and deploy it on Huawei Kunpeng Platform. Speedup curves of CESM components are prepared in advance based on sampling tests. Experimental data show that our algorithm reduces up to 52.6% of execution time compared with CESM default strategy. We also present simulation data to show that our algorithm is efficient for the platforms with up to a million cores.