Removable Storage White Papers
Systems Support for Preemptive Disk Scheduling
Overview Allowing higher-priority requests to preempt ongoing disk IOs is of particular benefit to delay-sensitive and real-time systems. This paper presents Semi-preemptible IO, which divides disk IO requests into small temporal units of disk commands improve the preemptibility of disk access. This paper first lay out main design strategies to allow preemption of each component of a disk access - seek, rotation, and data transfer, namely, seek-splitting, JIT-seek, and chunking. It then presents the preemption mechanisms for single and multidisk systems - JIT-preemption and JIT-migration. The evaluation of the prototype system showed Semi-preemptible IO substantially improved the preemptibility of disk access with little loss in disk throughput and that preemptive scheduling could improve the response time for high-priority interactive requests.
| Publisher | Institute of Electrical and Electronics Engineers | File Format | |
|---|---|---|---|
| Date Published | October 2005 | ||
| Format | White Papers | ||
| Topics | |||
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