Evaluating the impact of OpenMP 4.0 extensions on relevant parallel workloads

OpenMP has been for many years the most widely used programming model for shared memory architectures. Periodically, new features are proposed and some of them are finally selected for inclusion in the OpenMP standard. The OmpSs programming model developed at the Barcelona Supercomputing Center (BSC) aims to be an OpenMP forerunner that handles the main OpenMP constructs plus some extra features not included in the OpenMP standard. In this paper we show the usefulness of three OmpSs features not currently handled by OpenMP 4.0 by deploying them over three applications of the PARSEC benchmark suite and showing the performance benefits. This paper also shows performance trade-offs between the OmpSs/OpenMP tasking and loop parallelism constructs and shows how a hybrid implementation that combines both approaches is sometimes the best option.This work has been partially supported by the European Research Council under the European Union's 7th FP, ERC Grant Agreement number 321253, by the Spanish Ministry of Science and Innovation under grant TIN2012-34557 and by the HiPEAC Network of Excellence. It has been also supported by the Severo Ochoa Program awarded by the Spanish Government (grant SEV-2011-00067) M. Moreto has been partially supported by the Ministry of Economy and Competitiveness under Juan de la Cierva postdoctoral fellowship number JCI- 2012-15047. M. Casas is supported by the Secretary for Universities and Research of the Ministry of Economy and Knowledge of the Government of Catalonia and the Co- fund programme of the Marie Curie Actions of the 7th R&D Framework Programme of the European Union (Contract 2013 BP_B 00243).Peer ReviewedPostprint (author's final draft