A Hybrid DVS Scheme for Interactive 3D Games

Interactive 3D games are now widely available on a variety of mobile devices for which battery-life is a major concern. Many of these devices support voltage/frequency-scalable processors and dynamic voltage scaling (DVS) has emerged as a powerful technique for energy management in such devices. Although DVS algorithms have been very successfully applied to video encoding/decoding applications, their use in interactive computer games has not been sufficiently explored so far. In this paper we propose a novel DVS scheme that is specifically directed towards interactive 3D game applications running on battery-operated portable devices. The key to this DVS scheme lies in an accurate prediction of the rendering workload of a current game scene. We have applied this scheme to first person shooter games (e.g. Quake II) and obtained significant power savings while maintaining high frame rates. Based on the observation that there exist two types of workload variations in such games, we compute the voltage/frequency setting for any game scene using a hybrid combination of two different techniques: (i) adjusting the workload prediction using a control-theoretical feedback mechanism, and (ii) analyzing the graphical objects in the current game scene by parsing the corresponding frame. Our scheme is significantly different from those commonly applied to video decoding applications (where only technique (i) is used) and has shown very encouraging results when evaluated with different setups (e.g. laptop running Windows, PDA running Windows Mobile and a configurable simulation platform).