SURF: Supervisory Control of User-Perceived Performance for Mobile Device Energy Savings

Two critical quality factors for mobile devices (e.g., smartphones, tablets) are battery life and apps' userperceived performance, e.g., responsiveness of user actions and frame rate of video playback. Sadly, state-of-the-art solutions have at least one of the following two limitations: 1) they cannot efficiently handle concurrent foreground apps and so may lead to performance imbalance and high energy consumption, 2) they try to regulate app performance periodically and thus may not efficiently handle the aperiodicity of user actions, which can result in poor responsiveness or high overheads. In this paper, we present SURF, Supervisory control of User-perceived peRFormance, which is designed to overcome the two limitations. First, it dynamically allocates resources to concurrent apps for balanced performance. Second, SURF uses supervisory control theory to handle the aperiodicity of user actions. SURF features a two-level architecture design that performs the two tasks at different time scales, according to their different overheads and timing requirements. We test SURF on several mobile device models with real-world opensource apps and show that it can reduce the CPU energy consumption by 30-90% compared to state-of-the-art solutions while causing no perceivable performance degradation.