Abstract: Linux operating system is playing a more and more important role in the high-performance computing environment, computer-cluster system, and the high-performance security gateway. Therefore understanding and mastering the network software’s performance of Linux operating is an important thing. Using Netslice, which is a tool for automated analysis of network software latency, thorough and comprehensive measurement and analysis of the network software latency of Linux operating system are presented in this paper. The results show that the processing latency of receiving a packet is more expensive than that of sending the same one. Further study indicates that the primary bottlenecks are misaligned data copying and context switching operations. Meanwhile, it is also found that Linux and FreeBSD have the same network software performance.