Fairness and Efficiency in Processor Sharing Protocols to Minimize Sojourn Times

We consider the problem of designing a preemptive protocol that is both fair and efficient when one is only concerned with the sojourn time of the job and not intermediate results. Our Fair Sojourn Protocol (FSP) is both efficient, in a strong sense (similar to the shortest remaining processing time protocol – SRPT), and fair, in the sense of guaranteeing that it outperforms processor sharing (PS) for every nonterminal job in every busy period for any sample path while providing the same performance for the terminal job. Our primary motivation is web serving in which the standard protocol is PS, while recent work proposes using SRPT or variants. Our work suggests both a framework in which to evaluate proposed protocols and an attractive new protocol, FSP. ∗Work supported in part by National Science Foundation Grant No. ANI–9730162. Email:[email protected], www:http://www.orie.cornell.edu/∼friedman †Work supported in part by National Science Foundation Grant No. DMI–0085165. Email: [email protected], www:http://www.orie.cornell.edu/∼shane