面向高密度闪存的内存页大小探索

Exploration of memory page size for high-density flash memory

近年来,固态硬盘SSD向高带宽、大容量的方向飞速发展。为了扩大SSD的容量,闪存页面从4 KB增长到了16 KB。然而,操作系统依然以4 KB内存页为粒度向SSD下发读写请求,导致应用难以充分利用SSD的高带宽。增加内存页面的大小,以使操作系统下发的I/O请求和SSD读写闪存的粒度统一是可能可行的解决方案。将首次深入探索内存页大小对系统I/O性能与SSD寿命的影响。具体来说,将内存页大小设置为16 KB,运行测试程序并将实验结果与4 KB内存页进行比较。得出以下结论:(1)16 KB内存页具有更好的读性能;(2)应用的写粒度决定了16 KB内存页的性能;(3)16 KB内存页放大了页内无效数据对SSD寿命的影响。

In recent years,solid state drives(SSDs)have witnessed rapid development towards higher bandwidth and larger capacity.To expand SSD capacity,the size of flash memory pages has increased from 4 KB to 16 KB.However,operating systems still issue read/write requests to SSDs with a 4 KB memory page granularity,making it difficult for applications to fully utilize the high bandwidth of SSDs.Increasing the size of memory pages to align the granularity of I/O requests issued by the operating system with the SSD's flash memory read/write operations could be a potential solution.This paper delves into the effects of memory page size on system I/O performance and SSD lifetime for the first time,including setting the memory page size to 16 KB,running benchmark tests,and comparing the results with those obtained using 4 KB memory pages.The key findings are as follows:(1)16 KB memory pages exhibit better read performance;(2)the write granularity of applications determines the performance of 16 KB memory pages;(3)16 KB memory pages amplify the impact of invalid data within pages on SSD lifetime.