ARC-H: uniform CPU scheduling for heterogeneous services

Extending our work on adaptive rate-controlled scheduling, we present a novel CPU scheduler for heterogeneous applications running on general purpose computers. Our scheduler can effectively support diverse application requirements without resorting to scheduling algorithms of diverse types. Rather it employs uniform rate-based sharing, and application heterogeneity is satisfied by partitioning CPU capacity into service classes, each with a different criterion for admission control. As a result, we are able to provide at once guaranteed performance, flexible allocation of rates with excellent scalability, as well as intermediate service classes offering tradeoffs between reserved rate utilization and the strength of guarantees. Our scheduler has been implemented in Solaris 2.5.1. It runs existing applications without modifications. We present extensive experimental results showing the scalability, efficiency guaranteed performance, and overload performance aspects of our scheduler. We also demonstrate the importance of priority inheritance implemented in our scheduler for stable system performance.