Evaluation of directive-based performance portable programming models. (24th July 2019)

• Record Type: Journal Article
• Authors: Lopez, M. Graham; Joubert, Wayne; Larrea, Veronica G. Vergara; Hernandez, Oscar; Haidar, Azzam; Tomov, Stanimire; Dongarra, Jack
• Is Part Of: International journal of high performance computing and networking. Volume 14:Number 2(2019)
• Page Start: 165
• Page End: 182
• Publication Date: 2019-07-24
• Subjects: OpenMP 4 -- OpenACC -- performance portability -- programming models; High performance computing -- Periodicals; Computer networks -- Periodicals; High performance computing; Periodicals; 004.05
• Languages: English
• ISSNs: 1740-0562

Abstract

We present an extended exploration of the performance portability of directives provided by OpenMP 4 and OpenACC to program various types of node architectures with attached accelerators. To do this, we use examples of algorithms with varying computational intensities for our evaluation, as both compute and data access efficiency are important considerations for overall application performance. We implement the kernels of interest using various methods provided by newer OpenACC and OpenMP implementations, and we evaluate their performance on various platforms including both x86\_64 and Power8 with attached NVIDIA GPUs, X86\_64 multicores, self-hosted Intel Xeon Phi KNL, as well as an X86\_64 host system with Intel Xeon Phi coprocessors. Furthermore, we present in detail what factors affected the performance portability, including how to pick the right programming model, its programming style, its availability on different platforms, and how well compilers can optimise and target multiple platforms.