A Top-to-Bottom View: Energy Analysis for Mobile Application Source Code

Energy efficiency significantly influences user experience of battery-driven devices such as smartphones and tablets. The goal of an energy model of source code is to lay a foundation for energy-saving techniques from architecture to software development. The challenge is linking hardware energy consumption to the high-level application source code, considering the complex run-time context, such as thread scheduling, user inputs and the abstraction of the virtual machine. Traditional energy modeling is bottom-to-top, but this approach faces obstacles when software consists of a number of abstract layers. In this paper, we propose a top-to-bottom view. We focus on identifying valuable information from the source code, which results in the idea of utilizing an intermediate representation, "energy operation", to capture the energy characteristics. The experiment results show that the energy model at such a high-level can reduce the error margin to within 10% and enable energy breakdown at function-level, which helps developers understand the energy-related features of the code.