Choir: a real-time middleware architecture supporting benefit-based proactive resource allocation

Asynchronous real-time distributed systems are inherently non-deterministic. To deal with such non-determinism's, we have developed a family of proactive resource management algorithms that support benefit-function based, end-to-end QoS management. This paper describes a middleware implementation of these algorithms, called Choir. The Choir middleware allows the user express the task end-to-end timeliness requirements using Jensen's benefit functions. Furthermore, the middleware system can transparently replicate, and possibly migrate the computational subtasks to conquer uncertainties such as workload fluctuations, changes of system resources, so that the system aggregate benefit is maximized. Initial experimental results suggest the effectiveness the Choir middleware.