Automatic configuration and run-time adaptation of distributed applications

Increased platform heterogeneity and varying resource availability in distributed systems motivates the design of resource-aware applications, which ensure a desired performance level by continuously adapting their behavior to changing resource characteristics. In this paper, we describe an application-independent adaptation framework that simplifies the design of resource-aware applications. This framework eliminates the need for adaptation decisions to be explicitly programmed into the application by relying on two novel components: (1) a tunability interface, which exposes adaptation choices in the form of alternate application configurations while encapsulating core application functionality, and (2) a virtual execution environment, which emulates application execution under diverse resource availability enabling off-line collection of information about the resulting behavior. Together, these components permit automatic run-time decisions on when to adapt by continuously monitoring resource conditions and application progress, and how to adapt by dynamically choosing the application configuration that is most appropriate for the prescribed user preference. We evaluate the framework using an interactive distributed image visualization application. The framework permits automatic adaptation to changes in CPU load and network bandwidth by choosing a different compression algorithm or by controlling the image transmission sequence so as to satisfy user preferences of visualization quality and timeliness.