Scalable Multi-node Fast Fourier Transform on GPUs

Abstract

In this paper, we present the details of our multi-node GPU-FFT library, as well its scaling on Selene HPC system. Our library employs slab decomposition for data division and MPI for communication among GPUs. We performed GPU-FFT on 1024 3 , 2048 3 , and 4096 3 grids using a maximum of 512 A100 GPUs. We observed good scaling for 4096 3 grid with 64 to 512 GPUs. We report that the timings of multicore FFT of 1536 3 grid with 196608 cores of Cray XC40 is comparable to that of GPU-FFT of 2048 3 grid with 128 GPUs. The efficiency of GPU-FFT is due to the fast computation capabilities of A100 card and efficient communication via NVlink.