(ToDo: document properly.)
It is possible to compile Glasgow Haskell programs so that they will count lots and lots of interesting things, e.g., number of updates, number of data constructors entered, etc., etc. We call this "ticky-ticky" profiling, because that's the sound a Sun4 makes when it is running up all those counters (slowly).
Ticky-ticky profiling is mainly intended for implementors; it is quite separate from the main "cost-centre" profiling system, intended for all users everywhere.
To be able to use ticky-ticky profiling, you will need to have built appropriate libraries and things when you made the system. See "Customising what libraries to build," in the installation guide.
To get your compiled program to spit out the ticky-ticky numbers, use a `-r' RTS option.