In prior work on multiprocessor fairness, efficient techniques with provable properties for reallocating spare processing capacity have been elusive. In this paper, we address this shortcoming by proposing a new notion of multiprocessor fairness, called quick-release fair (QRfair) scheduling, which is a derivative of Pfair scheduling that allows efficient allocation of spare capacity. Under QRfair scheduling, each task is specified by giving both a minimum and a maximum weight (i.e., processor share). The goal is to schedule each task (as the available spare capacity changes) at a rate that is (i) at least that implied by its minimum weight and (ii) at most that implied by its maximum weight. Our contributions are fourfold. First, we present a quick-release variant of the PD2 Pfair scheduling algorithm called PDQ . Second, we formally prove that the allocations of PDQ always satisfy (i) and (ii). Third, we consider the problem of defining maximum weights in a way that encourages a f...
James H. Anderson, Aaron Block, Anand Srinivasan