HPSM: a programming framework to exploit multi-CPU and multi-GPU systems simultaneously

This paper presents a high-level C++ framework to explore multi-CPU and multi-GPU systems called HPSM. HPSM enables execution of parallel loops and reductions simultaneously over CPUs and GPUs using three parallel backends: Serial, OpenMP, and StarPU. We analysed HPSM development effort with AXPY program through two standard metrics (NCLOC and ES). In addition, we evaluated performance and energy with three parallel benchmarks: N-Body, Hotspot, and CFD solver. HPSM reduced code effort by up to 56.9% compared to StarPU C interface, although it resulted in 2.5x more lines of code compared to OpenMP. The CPU-GPU combination attained speedup results with Hotspot of up to 92.7x on a X86-based system with four GPUs and up to 108.2x on an IBM POWER8+ system with two GPUs. On both systems, the addition of GPUs improved energy efficiency.