Task-based programming models for shared memory-such as Cilk Plus and OpenMP 3-are well established and documented. However, with the increase in parallel, many-core, and heterogeneous systems, a number of research-driven projects have developed more diversified task-based support, employing various programming and runtime features. Unfortunately, despite the fact that dozens of different task-based systems exist today and are actively used for parallel and high-performance computing (HPC), no comprehensive overview or classification of task-based technologies for HPC exists. In this paper, we provide an initial task-focused taxonomy for HPC technologies, which covers both programming interfaces and runtime mechanisms. We

No abstract

Optimization of MPI collective communication operations has been an active research topic since the advent of MPI in 1990s. Many general and architecturespecific collective algorithms have been proposed and implemented in the state-of-theart MPI implementations. Hierarchical topology-oblivious transformation of existing communication algorithms has been recently proposed as a new promising approach to optimization of MPI collective communication algorithms and MPI-based applications. This approach has been successfully applied to the most popular parallel matrix multiplication algorithm, SUMMA, and the state-of-the-art MPI broadcast algorithms, demonstrating significant multifold performance gains, especially for large-scale HPC systems. In this paper, we apply this approach to optimization of the MPI Reduce and Allreduce operations. Theoretical analysis and experimental results on a cluster of Grid'5000 platform are presented.

No abstract

No abstract