Towards exascale with the ANR / JST japanese-french project FP3C (Framework and Programming for Post- Petascale Computing)

The Japanese-french project FP3C targets the post-petascale and the next generation of exascale systems. Its goal is to study the software technologies, languages and programming models to achieve the performance promised by post-petascale computing. The project consortium regroups some of the HPC key players in Japan and in France: * Universities of Kyoto, Tokyo and Tsukuba, Tokyo Institute of Technology, Japanese- French Laboratory on Informatics * CEA Saclay, CNRS (IRIT and PRISM), INRIA (Bordeaux, Rennes and Saclay), with a strong connection with RIKEN AICS at Kobe in Japan. The ability to efficiently program and exploit these future high performance systems is considered as a strategical issue by all research national agencies worldwide. The exascale computers are expected to a large-scale highly hierarchical architecture with many-core processsors possibly mixed with accelerators with up to millions of cores and threads. As a consequence, existing operating and runtime systems, languages, programming paradigms and parallel algorithms would have, at best, to be adapted, and may become often obsolete. Exploiting these ultra large-scale parallelsystems will require runtime systems allowing the management of huge amount of distributed data, minimizing the energy consumption, and exhibiting fault resilient properties. In addition to these features, accelerating technology, based on GPGPU and many-core processors, are also crucial issues for post-petascale computing systems. Efficient exploitation (programing, execution) of large scale systems is an important challenge. The hierarchical nature of these architecture and the scalability issues (parallelization at different level: intra / inter computational nodes composed of many core processors and/or accelerators) complexifies the algorithm design. Existing programming framework and runtime systems together with new approaches should be examined, experimented andevaluated. Benchmarks and libraries adapted to the post-petascale systems will have to be proposed. The FP3C project aims at defining a framework for high performance computing on the road to exascale. We cover most of the issues related to the emergence of post- petascale computing: from high level languages to efficient exploitation of the underlying architecture at the runtime level or using specific extensions for accelerators. Our approach is illustrated with experiments on a set of numerical codes (including numerical libraries) that can be seen as a benchmark. One of the goal of the project is to proceed to experiments on some of the most recent computers available in Europe (e.g. CURIE Computer at TGCC/France) and in Japan (e.g. K Computer at Kobe)