A Flexible and Dynamic Page Migration Infrastructure based on Hardware Counters
Performance counters, also known as hardware counters, are a powerful monitoring mechanism included in the Performance Monitoring Unit (PMU) of most of the modern microprocessors. Their use is gaining popularity as an analysis and validation tool for profiling, since their impact is virtually imperceptible and their precision has noticeably increased thanks to the new Precise Event-Based Sampling (PEBS) features. In this paper, we present and evaluate a novel user-level tool, based on hardware counters, for monitoring and migrating pages dynamically. This tool supports different migration strategies, being able to attach and monitor a target application without need to modify it whatsoever. The page migration process is performed timely and its overhead is overcome by the benefit of the data locality achieved. As a case study, an access-based migration algorithm was implemented and integrated into our tool. Performance results on a NUMA system show a noticeable reduction of remote accesses and execution time, achieving speedups of up to ∼21 % in a multiprogrammed environment.
keywords: Hardware counters, Page migration, NUMA