[Haskell-cafe] GHC 6.10.1 multi-threaded broken?

Don Stewart dons at galois.com
Sat Nov 29 14:42:51 EST 2008

> Hi,
> Since I upgraded from ghc 6.8.3 to 6.10.1, I noticed that my programs
> do not run multi-threaded anymore. I tried simplifying my code, till I just
> took one of the par/pseq demo's to verify if it wasn't my fault.

This sounds like the change to the scheduler where only 1 spark
won't trigger the other core to wake up.

See this mail from Simon Marlow,


    "I'll make sure it gets fixed for 6.10.2.  If you have more sparks then
    you shouldn't see this problem.  Also, GHC HEAD is quite a lot better
    with parallel programs than 6.10.1, I'll try to get around to posting
    some figures sometime."

More information about the Haskell-Cafe mailing list