[Haskell-cafe] why is haddock so slow

I have a larg-ish project (800 modules) and these ghc compilation times: cabal install : 19 min cabal install --disable-doc : 13 min the compilation includes the profiling build. That is, running haddock takes the same 6 minutes as running the compiler (with optimization) I also built with "optimization: False library-profiling: False" and this takes 3 min. I understand that haddockification goes via the compiler's front-end to resolve names and infer types. This takes 3 min (as the non-optimizing compiler run shows). What does haddock do in the other 3 min? What could I do to help analyze this? - J.W. (ghc-7.8.3, haddock 2.15.0, rotating disk (not SSD), Fedora 20, x86_64)