Event-Based Scheduling for Energy-Efficient QoS (eQoS) in Mobile Web Applications

Mobile Web applications have become an integral part of our society. They pose a high demand for application quality of service (QoS). However, the energy-constrained nature of mobile devices makes optimizing for QoS difficult. Prior art on energy efficiency optimizations has only focused on the trade-off between raw performance and energy consumption, ignoring the application QoS characteristics. In this paper, we propose the concept of energy-efficient QoS (eQoS) to capture the trade-off between QoS and energy consumption. Given the fundamental event-driven nature of mobile Web ap-plications, we further propose event-based scheduling as an optimization framework for eQoS. The event-based scheduling automatically reasons about users ’ QoS requirements, and accurately slacks the events ’ execution time to save energy without violating end users ’ experience. We demonstrate a working prototype using the Google Chromium and V8 frame-work on the Samsung Exynos 5410 SoC (used in the Galaxy S4 smartphone). Based on real hardware and software mea-surements, we achieve 41.2 % energy saving with only 0.4 % of QoS violations perceptible to end users. 1