LOAD SHARING IN SOFT REAL-TIME DISTRIBUTED COMPUTER-SYSTEMS

In soft realtime distributed computer systems, 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 sharing algorithm to distribute the local overload to other system nodes. We examine several relatively simple approaches to load sharing and show that these simple realtime 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. Copyright © 1987 by The Institute of Electrical and Electronics Engineers, Inc.