【摘要】 针对龙芯2号原型系统中主要I/O数据通路上数据流的特点,设计并实现了一款适用于龙芯2号原型系统的北桥。在此北桥的设计中提出并实现了一种用于外部设备互连(PCI)主桥(PCI host bridge,PHB)的数据传输优化方法,这种方法通过自适应的写合并、PCI写数据及时收集重打包和采用固定开销的分阶段PCI读数据预取策略,提高了PCI主桥中数据传输的效率。实验结果表明,所设计的北桥可以充分的利用PCI总线带宽,并且在处理PCI总线上的直接内存访问(DMA)读数据流和处理器更新显卡显存的PCI写数据流时相对同类系统而言具有明显的性能优势。更多还原

【Abstract】 In order to meet the I/O requirement of the Godson-2 prototype system,a noah-bridge was designed and implemented according to the characteristics of the main I/O data flow in the system.This design introduced an optimized data streaming method,which was used for peripheral component interconnect (PCI) host bridge (PHB),to control PCI data stream between PCI bus and north-bridge.This method utilized self-suited write merging,in-time write data collecting and repackaging,two stage read data preloading with static resource consumption policies.The experiment results show that the implemented north-bridge performs well and fully utilizes PCI bus’s bandwidth.Compared with other similar sys- tems,this north-bridge performs better in processing direct memory access (DMA) read and renewing PCI graphic card’s memory.更多还原