Evaluation of a zero-copy protocol implementation

Internet services like the world-wide web and multimedia applications like news- and video-on-demand have become very popular over the last years. Since a high and rapidly increasing number of users retrieve multimedia data with high data rates, the data servers can represent a severe bottleneck. Traditional time and resource consuming operations, like memory copy operations, limit the number of concurrent streams that can be transmitted from the server, because of two reasons: (1) memory space is wasted holding identical data copies in different address spaces; and (2) a lot of CPU resources are used on copy operations. To avoid this bottleneck and make memory and CPU resources available for other tasks, i.e. more concurrent clients, we have implemented a zero-copy data path through the communication protocols to support high-speed network communication, based on UVM. In this paper, we describe the implementation and evaluation of the zero-copy protocol mechanism, and we show the potential for substantial performance improvement when moving data through the communication system without any copy operations