Breakpoint-based Lightweight Prefetching to Improve Application Response

Abstract

Prefetching disk blocks reduces subsequent disk access times, allowing applications to load and run more quickly. Successful prefetching depends on the accuracy with which upcoming disk I/O can be predicted, and many techniques are not particularly accurate, while incurring significant memory and CPU overheads. A new lightweight prefetching technique for general applications performs off-line analysis of application source code, to identify disk access patterns, and then inserts breakpoints. At run time, these breakpoints trigger prefetching based on a log of disk accesses. Average reductions of 30% in launch times and 15% in loading times were observed in experiments.