If you need to do any sort of benchmarking for Haskell libraries, I can't recommend Criterion (and Neil Brown's package Progression[1]) enough. It handles all t

If you need to do any sort of benchmarking for Haskell libraries, I can't recommend Criterion (and Neil Brown's package Progression[1]) enough. It handles all the details for lazy evaluation (NF vs WHNF, pure vs IO, etc) quietly behind the scenes, and uses a well-designed statistics analysis library to calculate the final numbers. Don Stewart has written a short introduction, Modern Benchmarking in Haskell[2]. It's worth mentioning that Criterion can be used for anything that can be called via the FFI -- I'm using it for benchmarking Python libraries, for example. [1] http://hackage.haskell.org/package/progression http://hackage.haskell.org/package/progression [2] http://donsbot.wordpress.com/2010/02/23/modern-benchmarking-in-haskell/ http://donsbot.wordpress.com/2010/02/23/modern-benchmarking-...