HPSF Conference 2025

SPECFEM++ is a suite of computational tools based on the spectral element method used to simulate wave propagation through heterogeneous media. The project aims to unify the legacy SPECFEM codes - three separate Fortran packages (SPECFEM2D, SPECFEM3D, and SPECFEM3D_globe) - into a single C++ package. This new package aims to deliver optimal performance across different architectures by leveraging the Kokkos library. In this presentation, I will outline our efforts to enhance CPU performance using explicit SIMD types (Kokkos::Experimental::simd). High vectorization throughput can be challenging, particularly because the data involved in spectral element assembly is not always organized cache-friendly. To address this, we have implemented a strategy that prefetches the data into cache-optimized scratch views of SIMD types before executing the SIMD operations. Additionally, we have optimized data layouts using custom-defined tiled layouts that improve cache locality. As a result of these optimizations, we have achieved approximately a 2.5x speed-up compared to auto-vectorized implementations.