Load Management in Loosely Coupled Multiprocessor Systems

Scheduling is a typical technique used to distribute the load in multiprocessor systems. Usually, the manager(dispatcher or operating system)schedule the tasks so that the average finish time is minimized. Constraints related to the characteristics of the load such as precedence relation, deadline time, etc. must be taken into consideration. With ever increasing applications of a new paradigm of divisible tasks in image processing and parallel processing, one must concentrate on the characteristics of the system such as processor speed, link speed, and processor interconnection topology when distributing the load. By exploiting queuing theory, we managed to find different bounds on the arrival rate(load) as a function of link speed, processor speed and the size of tasks. A flow control mechanism for different multiprocessor systems with different topologies is embedded in our analysis. Moreover, our model indicates to the design engineers, depending on the traffic intensity, which element(s)of a parallel system has to be upgraded or replaced to meet the new load. This, of course, has to be justified by cost consideration.