PowerSpy: fine-grained software energy profiling for mobile devices

Battery power capacity has shown very little growth, especially when compared with the exponential growths of CPU power, memory and disk space. Hence, battery power is frequently the most constraining resource on a mobile device. As a foundation for optimizing application energy usage on mobile devices, it is increasingly important to profile system-wide energy usage in order to accurately determine where the energy is going. Previous work on profiling energy usage has either required external hardware multimeters, provided coarse grain results or required modifications to the operating system or/and profiled application. We present PowerSpy, which tracks and reports the battery energy consumed by the different threads of a monitored application, the operating system, other applications in a multi-threaded environment along with I/O devices. Using PowerSpy, we are able to measure the power consumption of five diverse applications including a Web browser, VRML graphics browser, compiler and video player, all without requiring modification to the application's source code.