An approximate analysis of a UNIX macro process scheduler

A UNIX macro process scheduler, referred to as the Fair Share Scheduler (FSS), is a UNIX scheduling algorithm that allocates different shares of the processor capacity to different groups of processes. First, the scheduling algorithm is approximated by a generalized processor-sharing discipline. Then, a second approximation is made to derive the mean response times of the different groups and the optimal allocation of shares among the groups. Finally, an application is shown where substantial performance improvements are observed.