Proportional-share resource management is becoming increasingly important in today’s computing environments. In particular, the growing use of the computational resources of central service providers argues for a proportional-share approach that allows clients to obtain resource shares that reflect their relative importance. In such environments, clients must be isolated from one another to prevent the activities of one client from impinging on the resource rights of others. However, such isolation limits the flexibility with which resource allocations can be modified to reflect the actual needs of clients. We present extensions to the lottery-scheduling resource-management framework that increase its flexibility while preserving its ability to provide secure isolation. To demonstrate how this extended framework safely overcomes the limits imposed by existing proportional-share schemes, we have implemented a prototype system that uses the framework to manage CPU time, physical memory, and disk bandwidth. We present the results of experiments that evaluate the prototype, and we show that our framework enables clients of central servers to achieve significant improvements in performance.
