Performance analysis and optimization of Gyrokinetic Torodial Code on TH-1A supercomputer

In this study, we test and analyze the performance of Gyrokinetic Torodial Code(GTC) program. According to the analysis results, we port GTC\´s compute-intensive subroutines to GPU and speed up them on the "CPU+GPU" heterogeneous architecture of TH-1A supercomputer. Some optimization strategies are developed in this process, for example, subroutines are integrated to reduce the data transfer between host and device, GPU memory access is optimized to reduce the access latency and static keyword is designed before arrays\´ declaration to avoid unnecessary address allocation and data copy. Experiment results show that the performance of the subroutines ported to GPU is improved evidently, which is between 6 and 8 times, and the total performance of GTC could be improved by 3 to 4 times.