In addition to profiling the time and allocation behaviour of your program, you can also generate a graph of its memory usage over time. This is useful for detecting the causes of space leaks, when your program holds on to more memory at run-time that it needs to. Space leaks lead to longer run-times due to heavy garbage collector ativity, and may even cause the program to run out of memory altogether.
To generate a heap profile from your program, compile it as before, but this time run it with the -h runtime option. This generates a file <prog>.hp file, which you then process with hp2ps to produce a Postscript file <prog>.ps. The Postscript file can be viewed with something like ghostview, or printed out on a Postscript-compatible printer.
For the RTS options that control the kind of heap profile generated, see the section called Runtime options for profiling. Details on the usage of the hp2ps program are given in the section called hp2ps--heap profile to PostScript