On Balancing Energy Consumption, Rendering Speed, and Image Quality on Mobile Devices

Mobile games and other mobile graphics applications have become popular because untethered computing is convenient and ubiquitous entertainment is compelling. However, rendering graphics on mobile devices faces challenges due to limited system resources, such as battery energy, low memory and disk space. Real time frame rates, low energy consumption and high image quality are all desirable attributes of interactive mobile graphics. However, in many cases, achieving these objectives conflicts with each other. For instance, increasing mesh resolutions improves rendered image quality but consumes more battery energy (degrades energy efficiency). Heuristics that intelligently trade off these competing objectives are necessary. We propose a mobile graphics heuristic to minimize energy consumption while maintaining acceptable image quality and interactive frame rates. Over the lifetime of a mobile graphics application, scene complexity, animation paths, user interactivity and other elements all change its CPU and resource demands. We propose a heuristic that dynamically changes scene mesh LoDs and amount of CPU timeslices alloted to the mobile graphics application in order to select optimal operating conditions that balance rendering speed, energy conservation and image quality. We propose a workload predict model so that our heuristic can monitor both application workload and the availability of resources of mobile devices periodically, and adaptively determine how much resources will be allocated to applications. Our experiments show that our heuristic can reduce energy consumption by up to 60% while maintaining interactive frame rates and acceptable image quality.