Research and Implementation of Zero-Copy Technology in Linux

Zero-copy means during message transmission, there is no data copy among memory segments on any network node. When message is sent out, the data packets in user application space go through network interface directly and reach outside of network; and when message is receiving, the same way is used, means the data packets are transmitted into user application space directly. In order to implement the zero-copy, the main technology we used here is DMA data transmission technology and memory mapping technology. In this paper, we based on Linux (kernel version 2.6.11), by modifying its network device driver snull.c and improving on COW technology, we implement the zero-copy technology. The main method we used is the combination of MMAP and PROC procedures, and at the end, we also introduce the implementation of test program and the test strategies.