I agree the OS scheduler is likely to contribute to our different observations. I'll try to test with ghc-7.4-rc1 tonight to see if I get similar results to 7.2.1.
If you want to see some code I'll post it, although I doubt it's necessary. I would appreciate it if you (or someone else in the know) could answer a question for me: does the GHC runtime handle scheduling of code from Haskell threads (forkIO) and foreign callbacks (via FunPtr's) in the same way, or are there restrictions on which capability may handle one or the other (ignoring bound threads and the like)? Thank you, John L. On Mon, Jan 23, 2012 at 1:26 PM, Simon Marlow <marlo...@gmail.com> wrote: > I'll need to analyse the program to see what's going on. There was a small > change to the scheduler between 7.2.1 and 7.2.2 that could conceivably have > made a difference in this scenario, but it was aimed at fixing a bug rather > than improvement performance. > > Another possibility is a difference in OS scheduling behaviour between yours > and Daniel Fischer's setup. In microbenchmarks like this, it's easy for a > difference in OS scheduling behaviour to make a large difference in > performance if it happens consistently. > > Cheers, > Simon _______________________________________________ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
