A Simulation Study Of The Effects Of Various Job-Scheduling Algorithms In Computer Systems*
S. R. Clark, T. A. Rourke · INFOR Information Systems and Operational Research · 1972
A simulation model of a computer with a finite non-contiguous store is used to assess the performance of various queue selection algorithms and various quantum allocation algorithms under conditions which are selected to accentuate their respective differences. Improvements in the measure of i)crformance of up to 76 per cent are observed.The measure of performance used is the mean elapsed time multiplication factor (ETMF) suggested by Stimler.The effect of variation of the size of the store is studied for two combinations of queue selection algorithm and quantum allocation algorithm. Under certain circumstances, the addition of more storage produces a deterioration in the measure of performance. One of the contributing effects appears to be increased system overheads, and another, inadequacies in certain combinations of queue selection algorithm and quantum allocation algorithm.A comparison is made with an analytical equation for a non-preemptive feedback system with infinite capacity and zero swap time. The agreement between this and results from the simulation model is found to be very satisfactory.