Trace-Driven Modeling and Analysis of CPU Scheduling in Multiprogramming System Microscopic level job stream data obtained in a production environment by an event-driven software probe is used to drive a model of a multiprogramming computer system. The CPU scheduling algorithm of the model is systematically varied. This technique, called trace-driven modeling, provides an accurate replica of a production environment for the testing of variations in the system. At the same time alterations in scheduling methods can be easily carried out in a controlled way with cause and effects relationships being isolated. The scheduling methods tested included the best possible and worst possible methods, the traditional methods of multiprogramming theory, round-robin, first-come-first-served, etc., and dynamic predictors. The relative and absolute performances of these scheduling methods are given. It is concluded that a successful CPU scheduling method must be preemptive and must prevent a given job from holding the CPU for too long a period. CACM December, 1972 Sherman, S. Baskett III, F. Browne, J. C. scheduling, CPU scheduling,multiprogramming, performance measurement, trace driven models 4.10 4.20 4.31 4.32 CA721210 JB January 27, 1978 10:57 AM 2245 5 2245 2245 5 2245 2245 5 2245 2571 5 2245 3072 5 2245 3119 5 2245 1713 6 2245 2219 6 2245 2245 6 2245 2245 6 2245 2245 6 2245 2375 6 2245 2798 6 2245 2849 6 2245 2859 6 2245