Decomposing the queue length distribution of processor-sharing models into queue lengths of permanent customer queues

Research output: Book/ReportReportProfessional

11 Citations (Scopus)

Abstract

We obtain a decomposition result for the steady state queue length distribution in egalitarian processor-sharing (PS) models. In particular, for an egalitarian PS queue with $K$ customer classes, we show that the marginal queue length distribution for class $k$ factorizes over the number of other customer types. The factorizing coefficients equal the queue length probabilities of a PS queue for type $k$ in isolation, in which the customers of the other types reside \textit{ permanently} in the system. Similarly, the (conditional) mean sojourn time for class $k$ can be obtained by conditioning on the number of permanent customers of the other types. The decomposition result implies linear relations between the marginal queue length probabilities, which also hold for other PS models such as the egalitarian processor-sharing models with state-dependent system capacity that only depends on the total number of customers in the system. Based on the exact decomposition result for egalitarian PS queues, we propose a similar decomposition for discriminatory processor-sharing (DPS) models, and numerically show that the approximation is accurate for moderate differences in service weights.
Original language Undefined Enschede University of Twente, Department of Applied Mathematics 16 Published - 2005

Publication series

Name Memorandum Faculty of Mathematical Sciences University of Twente, Department of Applied Mathematics 1753 0169-2690

• MSC-90B22
• EWI-3573
• METIS-248082
• MSC-60K37
• IR-65937
• MSC-60K25