If you’ve ever needed to benchmark (or load test) a webserver, you’ll be familiar with Apache Benchmark (ab), a brilliant tool that will hammer your webserver with lots of concurrent requests and give you statistics, histograms and and graphs—everything apart from how hot the server got! This is useful to determine when things like the network and webserver processes hit some limit or other, but for a modern web application it is of limited use, because more than likely you’ll end up requesting a cached page over and over again.
Before I start, I should say this: I have nothing but admiration for good developers, and nothing in this article is meant to say otherwise. I started out as a C/C++ developer after I graduated, and after 15 months I figured out that I’m not very good at it. So I leave the code to the experts, and merely advise them as best I can. That is the spirit in which this article is written.