Program affinity performance models for performance and utilization

Multithreaded applications have a wide variety of behavior, causing complex interactions with today´s chip multiprocessor machines. Application threads may have large private working sets, and may compete for cache space and memory bandwidth. These threads benefit from large private caches. Other threads may share data or communicate, and thus, execute more quickly if using shared caches. Many applications fall somewhere in between, requiring careful thread-to-core assignments to maximize performance. Yet because of the large number of thread-to-core assignments on today´s chip multiprocessors, it is time and energy prohibitive to exhaustively try and determine the best assignment. In this paper, we present and demonstrate application performance models that predict application performance given a proposed thread-to-core assignment. We show how these models can be quickly built and used to select thread-to-core assignments for multiple programs and to improve system utilization.