Competitive Parallel Disk Prefetching and Buffer Management

We provide a competitive analysis framework for online prefetching and buffer management algorithms in parallel I/O systems, using a read-once model of block references. This has widespread applicability to key I/O-bound applications such as external merging and concurrent playback of multiple video streams. Two realistic lookahead models, global lookahead and local lookahead, are defined. Algorithms NOM and GREED based on these two forms of lookahead are analyzed for shared buffer and distributed buffer configurations, both of which occur frequently in existing systems. An important aspect of our work is that we show how to implement both the models of lookahead in practice using the simple techniques of forecasting and flushing. Given a ¤ -disk parallel I/O system and a globally shared I/O buffer that can hold upto ¥ disk blocks, we derive a lower bound of ¦¨§© ¤ on the competitive ratio of any deterministic online prefetching algorithm with §¥ lookahead. NOM is ...

• Type: Conference
• Year: 1997
• Where: IOPADS
• Authors: Rakesh D. Barve, Mahesh Kallahalla, Peter J. Varman, Jeffrey Scott Vitter
• Keywords: Global Lookahead, IOPADS 1997, Local Lookahead, Lookahead