计算PCIe的吞吐
PCIe吞吐依赖以下因素
>protocol overhead
>payload size
>completion latency
>flow control update latency
>characteristics of the devices that form the link
Protocol Overhead
如果是8B/10B的编码,那么需要25%的开销。
对于Gen2,每根lane 4Gbps(500MBps)