加权轮询策略的PCIExpress DMA控制器的设计与实现

Design and Implementation of PCI Express DMA Controller Based on Weighted Round Robin Policy

针对目前PCIExpress桥接芯片在全双工模式下不能很好地解决收发传输平衡的问题,提出了基于加权循环分时技术的DMA控制器。通过对Burst传输的分析,从体系结构和指令集两个层面阐述了片上DMA控制器设计的意义及价值,给出了加权循环分时技术的一种实现。对传输卡的测试实验显示,针对不同传输需求利用不同的轮询权重值对分时策略进行优化,最高能够获得37倍的加速比。

As the PCI Express bridge chips can not remain in sending and receiving balance under full-duplex mode, we develop a DMA controller based on Weighted Round Robin technology.Through the analysis of Burst transmission, the significance of the on-chip DMA controller design is described.Moreover, we propose an implementation of Weighted Round Robin technology in data transfer.The experiments show that carefully tuned Round Robin weight can make our DMA controller up to 37times faster than its original version.