We present the third generation of the C++-based open-source skeleton programming framework SkePU. Its main new features include new skeletons, new data container types, support for returning multiple objects from skeleton instances and user functions, support for specifying alternative platform-specific user functions to exploit e.g. custom SIMD instructions, generalized scheduling variants for the multicore CPU backends, and a new cluster-backend targeting the custom MPI interface provided by the StarPU task-based runtime system. We have also revised the smart data containers’ memory consistency model for automatic data sharing between main and device memory. The new features are the result of a two-year co-design effort collecting feedback from HPC application partners in the EU H2020 project EXA2PRO, and target especially the HPC application domain and HPC platforms. We evaluate the performance effects of the new features on high-end multicore CPU and GPU systems and on HPC clusters.

The complexity of modern HPC systems requires the use of new tools that support advanced programming models and offer portability and programmability of parallel and heterogeneous architectures. In this work we evaluate the use of SkePU framework in an HPC application from the neural computing domain. We demonstrate the successful deployment of the application based on SkePU using multiple back-ends (OpenMP, OpenCL and MPI) and present lessons-learned towards future extensions of the SkePU framework.

Programming upcoming exascale computing systems is expected to be a major challenge. New programming models are required to improve programmability, by hiding the complexity of these systems from application developers. The EXA2PRO programming framework aims at improving developers' productivity for applications that target heterogeneous computing systems. It is based on advanced programming models and abstractions that encapsulate low-level platform-specific optimizations and it is supported by a runtime that handles application deployment on heterogeneous nodes. It supports a wide variety of platforms and accelerators (CPU, GPU, FPGAbased Data-Flow Engines), allowing developers to efficiently exploit heterogeneous computing systems, thus enabling more HPC applications to reach exascale computing. The EXA2PRO framework was evaluated using four HPC applications from different domains. By applying the EXA2PRO framework, the applications were automatically deployed and evaluated on a variety of computing architectures, enabling developers to obtain performance results on accelerators, test scalability on MPI clusters and productively investigate the degree by which each application can efficiently use different types of hardware resources.