Queuing Network Model for Analyzing Influence of Exclusively Used Resource on Performance of Computer Systems

摘要

Job conflicts occur when accessing exclusively used resources in computer systems. A typical example is conflicts when accessing a group of updat-able files. When a job uses a part of these files, others are not allowed to access any of them. These conflicts affect the performance of the system significantly. In this paper, a queuing network model is introduced to analyze the influence conflicts have on the performance of computer systems. It is formed from an ordinary central server model by adding a resource and a resource waiting queue. To analyze how the number of visits of a job to the resource waiting queue affects its response time, the conditional expectation of the response time for the job conditioned by the number of visits to the resource waiting queue is approximately calculate by introducing an approximate Markov chain. The results reveal that the number of conflicts significantly affects the response time of the job. Numerical experiments show that the approximate results are very close to those for simulation.