Calm energy accounting for multithreaded Java applications

Energy accounting is a fundamental problem in energy management, defined as attributing global energy consumption to individual components of interest. In this paper, we take on this problem at the application level, where the components for accounting are application logical units, such as methods, classes, and packages. Given a Java application, our novel runtime system Chappie produces an energy footprint, i.e., the relative energy consumption of all programming abstraction units within the application. The design of Chappie is unique in several dimensions. First, relative to targeted energy profiling where the profiler determines the energy consumption of a pre-defined application logical unit, e.g., a specific method, Chappie is total: the energy footprint encompasses all methods within an application. Second, Chappie is concurrency-aware: energy attribution is fully aware of the multi-threaded behavior of Java applications, including JVM bookkeeping threads. Third, Chappie is an embodiment of a novel philosophy for application-level energy accounting and profiling, which states that the accounting run should preserve the temporal phased power behavior of the application, and the spatial power distribution among the underlying hardware system. We term this important property as calmness. Against state-of-the-art DaCapo benchmarks, we show that the energy footprint generated by Chappie is precise while incurring negligible overhead. In addition, all results are produced with a high degree of calmness.