Effects of compiler optimizations in OpenMP to CUDA translation

Abstract

One thrust of the OpenMP standard development focuses on support for accelerators. An important question is whether or not OpenMP extensions are needed, and how much performance difference they would make. The same question is relevant for related efforts in support of accelerators, such as OpenACC. The present paper pursues this question. We analyze the effects of individual optimization techniques in a previously developed system that translates OpenMP programs into GPU codes, called OpenMPC. We also propose a new tuning strategy, called Modified IE (MIE), which overcomes some inefficiencies of the original OpenMPC tuning scheme. Furthermore, MIE addresses the challenge of tuning in the presence of runtime variations, owing to the memory transfers between the CPU and GPU. MIE, on average, performs 11% better than the previous tuning system while restricting the tuning system time complexity to a polynomial function. © 2012 Springer-Verlag.