Re: Enormous FFI speedup observed

On 27/02/2012 10:46, Joachim Breitner wrote:

Hi,

as I wrote on http://www.joachim-breitner.de/blog/archives/546-GHC-7.4.1-speeds-up-arbtt-b... I observe an enormous speed up (22×) in arbtt, and it seems to be related to FFI function calls. The release notes do not give a hint what has changed to result in this speed up, so I’m curious whether someone here knows the reason, or can make a good guess?

A couple of guesses: Avoiding slop in pinned objects: http://hackage.haskell.org/trac/ghc/changeset/cc2ea98ac4a15e40a15e89de9e47f3... Stack chunks: http://hackage.haskell.org/trac/ghc/changeset/f30d527344db528618f64a25250a3b... but it's hard to know for sure without investigating more closely. Cheers, Simon