An open source server benchmarking tool commonly used when prototyping Web applications or when testing a Web server.
The httperf tool generates workloads to test HTTP servers, and it works with HTTP/1.0 and HTTP/1.1, as well as SSL. After you run httperf, it generates a report with information about the test, including the number of connections, rate of connections, request size, request rate, reply time/size and rate, and much more. It also provides a list of errors, if any.
Httperf resides on Google Code. It was written by David Mosberger, and it is released under the GPLv2. Many Linux distros, including Debian, Ubuntu, Fedora and openSUSE have httperf packaged already.
Learn more about server benchmarking with httperf in this ServerWatch article.