Solaris^TM Resource Management -- The Fair Share Scheduler

Peter Baer Galvin

The previous Solaris^TM Companion began coverage of the new Solaris 9 resource management features. This month continues the analysis by exploring the core of S9RM, the fair share scheduler. This scheduler provides precise control of CPU use, allowing optimum system resource use without conflict between applications and workloads.

The fair share scheduler (FSS) was available as an unbundled product before Solaris 9, and is included in the full Solaris 9 release at no charge. The Solaris 9 Resource Management package includes resource limits (discussed here previously), the FSS, resource pools, and the Internet protocol quality of service (IPQoS) facility (to be covered in the future). This suite is one of the key features of Solaris 9, along with the inclusion of SunScreen, new device support, and performance and reliability improvements. Solaris 9 is in the early adoption phase at most sites, and I hope this column will help Sun sites determine if and when to move to Solaris 9, and which features to adopt as part of the move or later in the Solaris 9 lifecycle.

Overview

Fair share scheduling is a concept dating from before 1988, when research into this scheduling concept resulted in a paper by J. Kay and P. Lauder being published in the Communications of the ACM. That paper and other information are available from http://citeseer.nj.nec.com/kay88fair.html. Publishing a research paper is a far cry from use in commercial operating systems and, in fact, few fair share schedulers have been implemented. They are not a general replacement for time-sharing schedulers, which are demand-based.