On Wed, Aug 5, 2009 at 6:59 PM, Thomas Witzel
<witzel.thomas@gmail.com> wrote:
2. I started with the very simple nfib example given in the manual for
Control.Parallel (Section 7.18). On my systems using multiple cores
makes the code actually slower than just using a single core. While
the manual cautions that this could be the case for certain
algorithms, I'm wondering whether this is the desired behaviour for
this example.
I'm using ghc 6.10.4 right now.
IIRC the development version of GHC has some major work to optimize concurrency, so it may be worth trying that. In particular I believe it executes sparks in batches, to reduce the overhead (which hopefully fixes your issue).