A adaptive scheduler for QoS support in Compose|Q

In this paper, we present the design and implementation. details of a flexible reflective scheduling framework, that. supports conjunctive scheduling of both tasks and messages within a distributed message based environment. In future, distributed environments will need to fine tune their systems to provide diverse services, oftentimes implementing dissimilar policies and functionality. We understand that future distributed systems would require their schedulers to be tailor-made or customizable to suit the. diverse workloads at different times. The framework is therefore fashioned to provide both coarse and fine grained scheduling, for better tunability and improved performance. Though this model is designed to work with any thread based system, we have investigated the applicability of these concepts on actors (active objects) within the Compose|Q framework. Scheduling of soft real time tasks are handled by the framework to conform to guarantees, even in the presence of normal time-sharing tasks. We expect that the proposed solution would be scalable while providing higher flexibility than simple task based scheduling.