Hydra is a high performance multi-threaded web server. Unlike traditional
multi-threaded web servers, Hydra uses a constant, but configurable, pool
of threads and each thread can handle several connections by multiplexing
the connections. This may remind you of a non-blocking server, and this is
true, but Hydra does not have the killing limitation of a non-blocking
server, the confinement to one CPU. Hydra will take advantage of every
available CPU in a system.

WWW: http://hydra.hellug.gr/