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

[Don Stewart]

yrn001:
> 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,

    http://www.haskell.org/pipermail/haskell-cafe/2008-November/050974.html

    "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."