Folks:

After our recent Slashdotting, I'm looking at our server performance :) 
  One thing I'm looking to do it run run a fastcgi version of rublog. 
Before I do that, though, I'd like to run some comparative numbers.

Can anyone recommend a decent, lightweight webserver load testing tool, 
something that'll send requests in parallel and measure response times 
and throughput?

Cheers

Dave