A New Approach for Investigation on Closed Type Network with Combination of HOL and Multi-Level RR Priorities Scheduling Strategies

W. Oniszczuk


In this document, I propose a new algorithm for computation of main measures of effectiveness in a closed type, two-centre network. A novel priority scheduling strategy for this type of networks is presented. In such model, first priority tasks, tasks that need only one phase to get processed, coming from separate sources are served with head-of-line (HOL) priority algorithms. Ali lower priority tasks, incoming from different sources, get served according to a HOL round robin scheduling strategy. Any tasks that require multiple phases of processing arę moved to the back of the task queue and they are re-executed with a lower priority. Presented here algorithm belongs to a Mean Value Analysis (MVA) group and the model, that is being discussed, can be treated as M/G/l/N finite source (closed type) priority queue with multi-phase scrvicing based on round robin strategies. A constant or random length of time, called quantum, is set for each task and then processed by the server. If it takes lortger to process a given task than its assigned value, the task gets movcd to the end of the queue with a lower priority and then re-executed. Although, the paper primarily studies two-centre network performance, l also address performance issues of other computer systems where round robin priority scheduling strategies are used. Described above algorilhm is proved in diverse settings and then, numerous numerical results that show its efficiency are given.

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ISSN: 1896-5334 (print), 2300-889X (online)

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