面向高性能应用的PCIe SSD的驱动设计

Driver design for PCIe SSD in high performance application

针对自主研制的PCIe SSD设备,设计实现了分层驱动程序。为减少传统设计中的设备驱动层次,降低协议开销,对高速并发的请求实现乱序处理以提高带宽,采用了2层驱动结构:上层驱动将设备注册为系统中的磁盘类设备,向应用层提供接口,并捕捉文件系统的请求转发给下层;下层驱动中采用了请求队列、中断聚合、请求TAG寄存器技术以处理并发乱序请求。通过2层驱动的配合,可正确将PCIe SSD挂载为系统中磁盘,有效提高系统并行度,降低输入输出请求产生的中断次数,提高了设备吞吐量。

In order to reduce the layers in traditional storage driver design, decrease the cost of protocol translating and implement out-of-order processing on high speed concurrent requests, we adopt a two-layer structure for the self-developed PCIe SSD （Solid State Drive）. The upper layer registers the device to the operating system as a disk device, provides an interface to the application layer and forwards the requests of the file system to the lower layer. The lower layer designs the request queue, interrupt aggregation and request TAG register to handle concurrent and out-of-order requests. Through the cooperation of the two layers, the PCIe SSD is mounted to the operating system as a disk device, achieves a high concurrency and reduces the average interrupt times while enhancing the throughput.