Spidermine: Low Overhead User-Level Prefetching

Abstract

Spidermine monitors the rate at which read requests are issued by an application, and thus detects bursts of disk reads. It then determines an address at which to insert a breakpoint into the application code or a library before each burst, and logs each breakpoint, together with the data required for the subsequent burst. When the application is subsequently run, Spidermine inserts breakpoints at each logged address by temporarily replacing the instruction. Spidermine is then invoked at each breakpoint, and prefetches the corresponding data blocks into the page cache. This use of breakpoints as triggers for prefetching eliminates the need for monitoring to determine when to prefetch data during program execution. Also, by operating at the user level, Spidermine avoids interference with other applications. Experiments on 11 benchmark applications demonstrated that Spidermine can reduce the time for launch by up to 54.1%, and for run-time data-loading by up to 70.1% on a hard disk drive, 13.3% and 47.0% respectively, on a solid-disk drive.