Title : Evaluation of Scheduling Heuristics for Non-Identical Parallel Processors

Approved: Sabah Randhawa An evaluation of scheduling heuristics for nonidentical parallel processors was performed. There has been limited research that has focused on scheduling of parallel processors. This research generalizes the results from prior work in this area and examines complex scheduling rules in terms of flow time, tardiness, and proportion of tardy jobs. Several factors affecting the system were examined and scheduling heuristics were developed. These heuristics combine job allocation and job sequencing functions. A number of system features were considered in developing these heuristics, including setup times and processor utilization spread. The heuristics used different sequencing rules for job sequencing including random, Shortest Process Time (SPT), Earlier Due Date (EDD), and Smaller Slack (SS). A simulation model was developed and executed to study the system. The results of the study show that the effect Redacted for Privacy of the number of machines, the number of products, system loading, and setup times were significant for all performance measures. The effect of number of machines was also found to be significant on flow time and tardiness. Several two-factor interactions were identified as significant for flow time and tardiness. The SPT-based heuristic resulted in minimum job flow times. For tardiness and proportion of tardy jobs, the EDDbased heuristic gave the best results. Based on these conclusions, a "Hybrid" heuristic that combined SPT and EDD considerations was developed to provide tradeoff between flow time and due date based measures. ©Copyright by Chun-Ho Kuo September 29, 1994 All Rights Reserved EVALUATION OF SCHEDULING HEURISTICS FOR NON-IDENTICAL PARALLEL PROCESSORS