Using Intrinsic Performance Counters to Assess Efficiency in Task-based Parallel Applications

摘要

The ability to measure performance characteristics of an application at runtime is essential for monitoring the behavior of the application and the runtime system on the underlying architecture. Traditional performance measurement tools do not adequately provide measurements of asynchronous task-based parallel applications, either in real-time or for postmortem analysis. We propose that this capability is best performed directly by the runtime system for ease in use and to minimize conflicts and overheads potentially caused by traditional measurement tools. In this paper, we describe and illustrate the use of the performance monitoring capabilities in the HPX [13] runtime system. We describe and detail existing performance counters made available through HPX's performance counter framework and demonstrate how they are useful to understanding application efficiency and resource usage at runtime. This extensive framework provides the ability to asynchronously query software and hardware counters and could potentially be used as the basis for runtime adaptive resource decisions. We demonstrate the ease of porting the Inncabs benchmark suite to the HPX runtime system, the improved performance of benchmarks that employ fine-grained task parallelism when ported to HPX, and the capabilities and advantages of using the in-situ performance monitoring system in HPX to give detailed insight to the performance and behavior of the benchmarks and the runtime system.