一种针对闪存的高效缓冲区置换算法

Efficient Replacement Algorithm for Flash Memory

随着闪存容量的不断增长和闪存应用的日益广泛,针对闪存的缓冲区管理已成为一个迫切需要解决的问题.针对闪存的写代价显著高于读代价的特性,提出一种针对闪存的页面置换算法LEAC.LEAC根据页面的读写负载和闪存的读写代价差异对换出页面引起的预期闪存访问开销进行评估,优先换出预期访问开销最低的页.实验表明,LEAC可以显著降低闪存访问开销.

With rapid increase of the density of flash memory and the emergence of new flash-based applications,it becomes a critical issue to provide efficient buffer management for flash memory.Different from magnetic disk,flash memory has several distinct characteristics.Therefore,it will result in poor performance to directly apply traditional magnetic-disk-based page replacement algorithms on flash.This paper focuses on the distinct characteristics of flash memory,such as asymmetric read/write speed,and presents a novel efficient flash-based buffer page replacement algorithm,called LEAC.LEAC evaluates the expected flash access costs of pages according to their read/write loads and read/write speed of flash memory,and replaces the page with least expected access cost first.The experimental results showed that LEAC could significantly reduce flash access cost.