UPMLIB: A Runtime System for Tuning the Memory Performance of OpenMP Programs on Scalable Shared-Memory Multiprocessors

Abstract

We present the design and implementation of UPMLIB, a runtime system that provides transparent facilities for dynamically tuning the memory performance of OpenMP programs on scalable shared-memory multiprocessors with hardware cache-coherence. UPMLIB integrates information from the compiler and the operating system, to implement algorithms that perform accurate and timely page migrations. The algorithms and the associated mechanisms correlate memory reference information with the semantics of parallel programs and scheduling events that break the association between threads and data for which threads have memory affinity at runtime. Our experimental evidence shows that UPMLIB makes OpenMP programs immune to the page placement strategy of the operating system, thus obviating the need for introducing data placement directives in OpenMP. Furthermore, UPMlib provides solid improvements of throughput in multiprogrammed execution environments.