Constraint-Driven Dynamic Adaptation of Mobile Applications for Quality of Service

Abstract. Modern mobile applications are executed in a variety of ex-ecution environments by users with different preferences for energy sav-ings, performance efficiency, reliability, and privacy. Offloading a mobile application’s functionality to execute at a remote server has become an important energy and performance optimization technique. Mobile appli-cations, however, executed over networks with divergent latency/band-width characteristics, access cloud-based servers that offer different levels of performance, availability, and privacy. An effective offloading mecha-nism must consider all these factors when determining which function-ality should be offloaded to which server. In addition, offloading can be used to save energy, improve performance, or both. Implementing an adaptive offloading mechanism driven by both runtime conditions and user preferences is non-trivial. In this paper, we present a novel approach to configurable, adaptive offloading for mobile applications that is driven by constraint solving. The programmer annotates energy intensive func-tionality at the method boundary. The end user, via a configuration menu, specifies how to prioritize energy savings, performance efficiency, server availability, and privacy. The specified priorities are then auto-matically translated into constraints used at runtime by a third-party constraint solver to drive an adaptive offloading runtime system. Key words: mobile applications, cloud offloading, energy optimization, constraint-solving, adaptation, software reengineering