Improving I/O Performance of Multimedia Servers
Pål Halvorsen · 2001
In the last years, there has been a tremendous growth in the use of Internet services. In particular, the world-wide web and applications like News- and Video-on-Demand have become very popular. Thus, the number of users, as well as the amount of data each user downloads from servers in the Internet, is rapidly increasing. The usage of multimedia data to represent information in a user-friendly way is one important reason for these two developments. Today, contemporary mid-price personal computers are capable of handling the load that such multimedia applications impose on the client system. However, the potentially (very) high number of concurrent users that download data from Media-on-Demand (MoD) servers represents a generic problem for this kind of client-server applications. In MoD servers, the data retrieval operations represent a severe bottleneck, because the clients concurrently retrieve data with high data rates. We have developed a new architecture for MoD servers that maximizes the number of concurrent clients that a single server can support. Traditional bottlenecks, like copy operations, multiple copies of the same data element in main memory, and checksum calculation in communication protocols are avoided by applying three orthogonal techniques: (1) the zero-copy-one-copy memory architecture removes all in-memory copy operations and shares a single