Measuring Congestion for Dynamic Task Allocation in Distributed Simulation

An important factor affecting the performance of distributed simulations running on parallel-processing computers is the allocation of logical processes to the available physical processors. An inefficient allocation can result in excessive communication times and unfavorable load conditions. This leads to long run times, possibly giving performance worse than that with a uniprocessor sequential event-list implementation. But the efficiency of any allocation strategy is dependent on the metric, or measure, it uses to characterize the load in the distributed system. This paper presents a simple and intuitive way of measuring and reallocating the load when the objective is to minimize simulation run time. The metric, based on estimating measures of message utilization at each processor, has been used in an adaptive scheme for load allocation, and experiments on an iPSC/2 Hypercube indicate that it successfully characterizes the load for purposes of reducing simulation run time. INFORMS Journal on Computing , ISSN 1091-9856, was published as ORSA Journal on Computing from 1989 to 1995 under ISSN 0899-1499.