In-kernel web server

An in-kernel web server is a (possibly limited) HTTP server that runs in kernel space or equivalent. Also called "accelerator".

Benefits

• more performant path taken by data from disk to network. Proper asynchronous zero-copy interfaces would make this available from user-space.
• higher scalability with respect to number of simultaneous clients. Event notification of comparable scalability seems impossible in user-spaceTemplate:Fn.

Drawbacks

• security
• portability. Every kernel needs a specific implementation.

Implementations

include:

• Solaris/NCAkmod
• HP-UX/NSAhttp
• Linux/khttpd
• Linux/TUX
• Windows NT/http.sys (part of IIS)
• SPIN/http
• OpenVMS/WASD.trap

See also

• comparison of web servers

References

• Template:FnbCITI_TR_00-4
• [http://www.sysinternals.com/files/webserver.pdf High-Performance Memory-Based Web Servers: Kernel and User-Space Performance. Philippe Joubert, Robert B. King, Rich Neves, Mark Russinovich, John M. Tracey.

IBM. T. J. Watson Research Center]