Cello: A Disk Scheduling Framework for Next Generation Operating Systems

In this paper, we present the Cello disk scheduling framework for meeting the diverse service requirements of applications. Cello employs a two-level disk scheduling architecture, consisting of a class-independent scheduler and a set of class-specific schedulers. The two levels of the framework allocate disk bandwidth at two time-scales: the class-independent scheduler governs the coarse-grain allocation of bandwidth to application classes, while the class-specific schedulers control the fine-grain interleaving of requests. The two levels of the architecture separate application-independent mechanisms from applicationspecific scheduling policies, and thereby facilitate the co-existence of multiple class-specific schedulers. We demonstrate that Cello is suitable for next generation operating systems since: (i) it aligns the service provided with the application requirements, (ii) it protects application classes from one another, (iii) it is work-conserving and can adapt to changes in w...

• Type: Journal
• Year: 2002
• Where: RTS
• Authors: Prashant J. Shenoy, Harrick M. Vin
• Keywords: Cello, Class-independent Scheduler, Class-specific Schedulers, RTS 2002