About cookies on this site Our websites require some cookies to function properly (required). In addition, other cookies may be used with your consent to analyze site usage, improve the user experience and for advertising. For more information, please review your options. By visiting our website, you agree to our processing of information as described in IBM’sprivacy statement. To provide a smooth navigation, your cookie preferences will be shared across the IBM web domains listed here.
Abstract
Adaptive Fast Path Architecture (AFPA) is a software architecture that dramatically improves the efficiency, and therefore the capacity, of Web and other network servers. The architecture includes a RAM-based cache that serves static content and a reverse proxy that can distribute requests for dynamic content to multiple servers. These two mechanisms are combined using a flexible layer-7 (content-based) routing facility. The architecture defines interfaces that allow these generic mechanisms to be exploited to accelerate a variety of application protocols, including HTTP. Efficiency is derived from maximizing the number of requests that are handled entirely within the kernel, using a deferred-interrupt context instead of threads wherever possible. AFPA has been implemented on several server platforms including Microsoft Windows NT® and Windows® 2000, OS/390®, AIX®, and most recently Linux. By conservative estimates, AFPA more than doubles capacity for serving static content compared to conventional server architectures, and has allowed IBM to establish a leadership position in Web server performance. A prototype implementation of AFPA on Linux delivers more than 10000 SPECweb96 operations per second on a single processor.