Whatâ€™s neat about DTrace is that this happens dynamically (hence the name). You donâ€™t have to do anything special to participate. Any function or method in your code can be traced.
DTrace has fascinated me for years. PostgreSQL added support in version 8.2 (add --enable-dtrace when installing via Homebrew) and it will be standard in Ruby 2.0, due in a few days. Sadly, I don’t think it will ever make it into Linux, so isn’t available for tracking down production issues in the most common UNIX server environment.