Cost-aware Programming on Page-based Distributed Shared Memory

Abstract

Page-based distributed shared memory (PDSM) is a programming environment on distributed-memory computers that allows to freely allocate shared regions in the virtual address space accessible from any computer. It hides distributed physical memory from programmers and enables shared-memory programming over the uniform virtual address space. PDSM systems are typically equipped with coherent cache to improve performance while hiding communication, but the management cost is considered implementation details and is complex and implicit. Conse-quently, it is easy to fail in gaining speedup, and it is difficult to perform cost-aware programming to solve it. In this study, we explore cost-aware programming for ArgoDSM, a state-of-the-art PDSM. Particularly, based on the ob-servation that there are three effective measures for reducing PDSM-derived costs: 1) informing PDSM of changes in access patterns to shared regions, 2) inspecting the data to be placed in shared regions, and 3) performing writes with an awareness of the original owner of the shared region, we extend the ArgoDSM with APIs to help in these measures. We performed cost-aware programming on the extended ArgoDSM for benchmark programs, and experimentally showed that PDSM-derived costs can be significantly reduced. The proposed programming measures significantly improve the situation, where the performance is below the sequential performance, and allows to benefit from the scalability of distributed-memory computers under the high-level abstraction of PDSM.