Kernel Support for System Call Performance Monitoring

[Yaoping Ruan]

We have been working on improving Web server performance on
FreeBSD, and think you may be interested in the results and
techniques we used. Specifically, we focus on the SpecWeb99
benchmark and the Flash Web Server, and have roughly quadrupled
its performance. We did this by adding support for a very
low-cost kernel performance monitoring system, which allowed
us to find and fix a number of bad interactions between the
server and the OS. We additionally augmented one of the system
calls, sendfile, to be more useful for this kind of server.
We think that our observations may be useful for other servers,
and may present opportunities for performance improvement in
FreeBSD.

A paper describing our system can be found at
http://www.cs.princeton.edu/~yruan/DeBox and we can provide the
patches we made if anyone's interested. We welcome any comments
and feedback that you have.

Sincerely

- Yaoping
yruan at cs.princeton.edu