Recent experiences in using MPI-3 RMA in the DASH PGAS runtime

Abstract

The Partitioned Global Address Space (PGAS) programming model has become a viable alternative to traditional message passing using MPI. The DASH project provides a PGAS abstraction entirely based on C++11. The underlying DASH RunTime, DART, provides communication and management functionality transparently to the user. In order to facilitate incremental transitions of existing MPI-parallel codes, the development of DART has focused on creating a PGAS runtime based on the MPI-3 RMA standard. From an MPI-RMA user perspective, this paper outlines our recent experiences in the development of DART and presents insights into issues that we faced and how we attempted to solve them, including issues surrounding memory allocation and memory consistency as well as communication latencies. We implemented a set of benchmarks for global memory allocation latency in the framework of the OSU micro-benchmark suite and present results for allocation and communication latency measurements of different global memory allocation strategies under three different MPI implementations.