language: en

Proportional-Share Scheduling: Implementation and Evaluation in a Widely-Deployed Operating System

David Petrou and John Milford
dpetrou@cs.cmu.edu, jwm@csua.berkeley.edu

[Draft 12/20/1997. Send feedback to the authors.]

Abstract This paper explores the feasibility of using lottery scheduling, a proportional-share resource management algorithm, to schedule processes under the FreeBSD operating system. Proportional-share scheduling enables flexible control over relative process execution rates and processor load insulation among groups of processes. We show that a straight implementation of lottery scheduling performs worse than the standard FreeBSD scheduler. This initial result prompted us to extend lottery scheduling. Except for one test we run, our resulting system performs within one percent of the FreeBSD scheduler. We describe our design, evaluate our implementation, and relate our experience in deploying our lottery scheduler on production machines.

1 Introduction