An Implementation and Evaluation of Thread Subteam for OpenMP Extensions

OpenMP provides a portable programming interface on shared memory multiprocessors (SMPs). The set of features in the current OpenMP specification provides essential functionality that was selected mostly from existing shared-memory parallel application programming interfaces (APIs). Although this interface has proven successful for small SMPs, it requires greater flexibility in light of the steadily growing size of individual SMPs and the recent advent of multithreaded chips. In this paper, we introduce the syntax and semantics of a proposed OpenMP extension for facilitating the expression of worksharing on the emerging chip multithreading architectures. We also describe our implementation in the OpenUH reference OpenMP compiler and the runtime library. We then evaluate the new feature using a kernel of seismic data processing application.