Task scheduling in hard real-time distributed systems on a bus local area network

The authors propose a scheme for global scheduling in a distributed system using a bus network, which is shared by nodes in the system through a contention-free medium access protocol. Unlike existing solutions, the scheme does not require complete global state information to be collected for a node that has an unschedulable aperiodic task to find a node that can execute the task. The nodes are organized in the system in a logical ring fashion to synchronize the global scheduling process. To evaluate the performance of the scheme, two protocols are developed. Simulation results show that the performance of the scheme is close to an ideal distributed system, in which the centralized global scheduler takes care of aperiodic tasks without any communication and task migration overhead.<>