Computer Science Department
School of Computer Science, Carnegie Mellon University


Analysis of Cycle Stealing with Switching Cost

Takayuki Osogami, Mor Harchol-Balter, Alan Scheller-Wolf

November 2002

Keywords: Cycle stealing, switching cost, queueing theory, task assignment, server farm, distributed system, unfairness, starvation, load sharing, supercomputing, Matrix-Analytic.

We consider the scenario of two independent processors, each serving its own workload, where one of the processors (known as the "donor") can help the other processor (known as the "beneficiary") with its jobs, during times when the donor processor is idle. That is the beneficiary processor "steals idle cycles" from the donor processor. We assume that both donor jobs and beneficiary jobs may have generally-distributed service requirements. We assume that there is a switching cost required for the donor processor to start working on the beneficiary jobs, as well as a switching cost required for the donor processor to return to working on its own jobs. We also allow for threshold constraints, whereby the donor processor only initiates helping the beneficiary if both the donor is idle and the number of jobs at the beneficiary exceeds a certain threshold.

We analyze the mean response time for the donor and beneficiary processors. Our analysis is approximate, but can be made as close to exact as desired. Analysis is validated via simulation. Results of the analysis illuminate several interesting principles with respect to the general benefits of cycle stealing and the design of cycle stealing policies.

31 pages

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