From Molecular Dynamics to Oceanography - Ookami Graduate Students Porting and Tuning Science Codes for A64FX.

To build a cohort of computationally educated young researchers and to deepen community expertise, the Ookami project is actively integrating graduate students into the project team. They learn how to get started on a novel architecture and what to take care of when porting applications. This experience enables them to do production research on A64FX as well as grow their general knowledge in HPC, benefiting not just them but also the codes they are working on. Embedding them within the project team greatly facilitates the transfer of skills, builds a common vocabulary and culture, provides experience in large project execution, and builds confidence and a can-do attitude. In this paper, we report the student’s preliminary efforts in porting several science applications to Fujitsu A64FX. The Arm-based Fujitsu A64FX processor developed by Fujitsu and RIKEN is used in Fugaku, which until June 2022 has been the fastest machine worldwide for two years. Its main features of SVE, HBM, and being power efficient makes it unique in the world of HPC. The studied applications (SIESTA, MOM6, Amber, ROMS) are from various disciplines and give a good overview of the A64FX porting process.