Multiple-SPMD Programming Environment Based on PGAS and Workflow toward Post-petascale Computing

In this paper, we propose a new development and execution environment based on workflow and PGAS methodologies for parallel programmings in post-petascale systems. It is expected that post-petascale systems will have a huge and highly hierarchical architecture with nodes of many-core processors and accelerators. For current parallel programs, MPI, MPI/OpenMP hybrid, and so on, it would be sometimes difficult to exploit the post-petascale systems efficiently. The proposed environment, called FP2C (Framework for Post-Petascale Computing), supports multi-program methodologies across multi-architectural levels. It introduces a PGAS parallel programming language called XcalableMP (XMP) to describe tasks into a workflow environment called YML. FP2C is composed of three layers: (1) workflow programming, (2)distributed programming, and (3) shared-memory parallel programming/accelerator. Computational experiments suggest that effective use of cores and memories can be achieved by controlling the level of hierarchization using FP2C.