POWSER: A novel user-experience based power management metric

With the rapid increase in deployment of a variety of applications on mobile devices, and an increasing amount of activity and time spent on the devices, battery life continues to be a major source of concern. At the same time, hardware and software advances in mobile computing have enabled multiple usage functions to be integrated into one device, making energy consumption of the device more critical. Some approximations in computing can be made without noticeable degradation in quality to achieve savings in power. We explain the concept of user-experience based power management (UEPM) and propose a novel simple to use user-perceived-quality-energy metric called POWSER to build a UEPM-based system with a holistic objective. POWSER can also provide optimal operating points for the applications to perform fast dynamic online optimizations of applications such as video. Quality-energy tradeoffs have been carried out at various levels before. However, existing approaches do not take the final user-experience into account. POWSER is an easy to compute and easy to use weighted metric based on the nature of quality-energy tradeoffs. POWSER models QoS parameters in software that can be propagated down to hardware to implement further power savings across the system stack. Keeping acceptable user experience, POWSER provides an optimal set of operating points for each application by exploiting power savings of up to 34% in image applications.