Load Sharing in Soft Real-Time Distributed Computer Systems

Abstract
in soft real-time distributed computer stems, a job submitted at a node in the network must complete execution within a specified time constraint, otherwise it is considered lost. When a single node occasionally experiences an overload of jobs, it may still be possible to execute some of the otherwise lost jobs by invoking a load sharingnode algorithm to distribute the local overload to other system nodes. We examine several relatively simple approaches to load sharing and show that these simple real-time load sharing algorithms may often perform as well as their more complex counterparts. Approximate analytic performance models are developed and validated through simulation. The performance results suggest that, over a relatively wide range of system parameters, the performance of these simple approaches is substantially better than the case of no load sharing and often close to that of a theoretically optimum algorithm.