User experience enhanced task scheduling and processor frequency scaling for energy-sensitive mobile devices

Mobile devices such as smartphones, tablets and various tiny smart equipment are widely subjected to the limit of energy consumption. Moreover, user experience has become an up-to-the-moment research topic in mobile devices. In most mobile devices, the processor is usually set in a higher frequency level to provide better performance, which would cause the increment of energy consumption. In order to address this issue, in this paper, we propose a novel task scheduling model to harvest the energy saving and user experience improvement in energy-sensitive mobile devices. In our task scheduling model, we introduce the concept of user-centric task, and present tow judgmental principles to determine user-centric tasks (i.e., foreground/interactive tasks). For enhancing user experience, we reduce slack time of the user-centric tasks properly to achieve a shorter response time. We then present two algorithms to calculate the optimal frequencies and allocate the CPU resources. The experimental evaluation results show that our task scheduling model can achieve a tradeoff between energy consumption and performance, and enhance user experience.