High performance implementation of nuclear fusion simulation code on GPU cluster

Matsumoto, Kazuya; Asahi, Yuichi*   ; Ina, Takuya; Idomura, Yasuhiro   

We present the implementation and performance evaluation results of the plasma physics simulation code called GT5D on a GPU cluster. In this study, an iterative matrix solver, which is identified as a performance bottleneck in the code, is tuned on the GPU. The measured performance is compared with attainable performance calculated by the roofline model. Additionally, we show the implementation with direction communications between GPUs for utilizing many GPUs.