主机和设备协作方式提升固态硬盘随机读取性能

IMPROVING RANDOM READ PERFORMANCE OF SSD BY HOST AND DEVICE COLLABORATION

对一些不带DRAM的固态存储设备,由于映射表(逻辑地址到物理地址的映射表)不能完全存储在片上SRAM,需要读取两次闪存才能获得用户数据,因此随机读取性能受限。而今主机端的DRAM资源充足,故提出把设备端的映射表存储到主机端的DRAM,通过主机和设备协作的方式,设计和实现一种快速提升随机读取性能的算法。除了付出主机端DRAM资源代价之外,该算法无需硬件改动,通过纯软件实现,可以在当前几乎所有的接口协议上定制实现,以改善无DRAM的固态存储设备的随机读取性能。实验结果表明,该算法几乎能使没有DRAM的存储设备随机读取性能翻倍。

For some DRAM-less solid-state storage devices,it normally takes 2 times to access the flash to get the user data as the limited SRAM on the device can only hold parts of the mapping table(logical address to physical address),therefore,the random read performance is limited.Noting that the DRAM resource on host side is abundant nowadays,this paper proposes to put the mapping table of the device to the host side DRAM.A fast-random read algorithm is designed and implemented through the cooperation between the host and the device.Expect the cost of host DRAM resources,it does not require hardware changes.This algorithm can be implemented on almost all current host interface and protocol via pure software change to improve the random read performance of DRAM-less SSD.The experimental results show the algorithm can almost double the random read performance of DRAM-less storage devices.