The name probably gives it away, but httperf is a tool
that generates workloads to test HTTP servers. It works with
HTTP/1.0 and HTTP/1.1, as well as SSL if needed. It was written by
David Mosberger for HP, and it is released under the GPLv2.
The tool has moved around a bit; it was initially hosted on
SourceForge but now resides on Google Code. It's worth noting that
httperf is fairly mature and not changing a lot at this point. The
most recent release (0.9) is a few years old, but that shouldn't be
a problem. Most Linux distros have httperf packaged already, so if
you're on Debian, Ubuntu, Fedora, openSUSE and so on, you should
just be able to grab it from the distribution repositories. If not,
the tarball is on Google Code.