Acceleration of stencil-based fusion kernels

Asahi, Yuichi*   ; Latu, G.*; Ina, Takuya; Idomura, Yasuhiro   ; Grandgirard, V.*; Garbet, X.*

Computation kernels of fusion plasma turbulence codes based on the Semi-Lagrangian scheme and the Finite-Difference scheme are optimized on latest many core processors such as GPGPU, XeonPhi, and FX100, and 1.4x-8.1x speedup is achieved. Affinity between different memory access patterns in each numerical scheme and difference memory-cache architectures on each hardware is studied, and different optimization techniques are developed for each architecture. On Xeon Phi, thread load balance is improved, and an optimization technique for effective local cache usage is developed. On GPGPU, an optimization technique using a texture memory and an implementation to reuse registers are developed. On the other hand, on FX100, it is found that the conventional optimization techniques for CPU work.