I've just created a web chat server with Tornado over Python. The communication mechanism is to use long-polling and I/O events.
I want to benchmark this web chat server at large scale, meaning I want to test this chat server (Tornado based) to see how many chatters it can withstand.
Because I'm using cookies to identify sessions, presently I can only test with maximum 5 (IE, Firefox, Chrome, Safari, Opera) sessions per computer (cookie path has no use coz everything goes thru' the same web page), but in my office we only have limited number of computers.
I want to test this Tornado app at the extreme, hopefully it can withstand few thousand concurrent users like Tornado is advertising, but having no clue how to do this!
I would run the server in a mode where you let the client tell which client they are. i.e. change the code so it can be run this way as required.  This is less secure, but makes testing easier. In production, don't use this option.  This will give you a realistic test from a small number of client machines.
How to benchmark web chat performance?