基于PCI+Express 2.0的高速网卡中DMA的设计

The Design of DMA In High Speed NIC Based on PCI Express 2.0

PCIE总线已经成为高带宽网卡与计算机通信的主流总线。而DMA控制器是实现PCIE总线高带宽应用的关键因素。本文详细阐述了基于PCIE接口的网卡中DMA引擎的接收和发送数据过程,介绍了描述符机制。本文提出了基于PCIE接口的网卡DMA的设计方案,并详细说明了其中的实现难点和各子模块的功能。本文还提出了影响DMA性能的主要因素和改进方向。

PCI Express bus has become the mainstream bus applied communication between high-bandwidth NIC and computer.DMA controllor is a key element to achieve high bandwidth utilization for a PCI Express application.This paper describes the descriptor mechanism and the processes of receiving and sending data packets of the DMA.This paper proposes a design architecture to implement DMA in NIC based on PCI Express.The paper also raises the main factors and the direction of the DMA improving performance.