Profiterole

Script for reading and restructring a GHC profile script.

The Goal

Given profile data, different ways of looking at it reveal different insights. This tool provides one of those insights - in addition to reading the standard profile output and using other tools such as Profiteur.

Profiterole aims to make the profile shorter by combining common subtrees and lifting them to the root - e.g. if you call parseFile from 7 places in the code, instead of having 7 pieces of parseFile profiling, Profiterole will give you one.

As an example compare HLint profile input to HLint Profiterole output.

Usage

To run, first install (cabal update && cabal install profiterole), generate a GHC profile the normal way, then run:

profiterole myprogram.prof

Profiterole will generate myprogram.profiterole.txt and myprogram.profiterole.html - both contain the same information, but the HTML has hyperlinks. There are three columns of numbers:

• TOT is the total time spent in any item under this code, what GHC calls inherited time.
• INH is the total time spent in the items that Profiterole did not move out to the top level.
• IND is the individual time, just like GHC profiles.

For large programs, using +RTS -P (instead of the common -p) will give more accurate results.