<br><br><div class="gmail_quote">On Wed, Aug 5, 2009 at 6:59 PM, Thomas Witzel <span dir="ltr"><<a href="mailto:witzel.thomas@gmail.com">witzel.thomas@gmail.com</a>></span> wrote:<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
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2. I started with the very simple nfib example given in the manual for<br>
Control.Parallel (Section 7.18). On my systems using multiple cores<br>
makes the code actually slower than just using a single core. While<br>
the manual cautions that this could be the case for certain<br>
algorithms, I'm wondering whether this is the desired behaviour for<br>
this example.<br>
<br>
I'm using ghc 6.10.4 right now.<br></blockquote><div><br></div><div>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). </div>
</div><br clear="all"><br>-- <br>Sebastian Sylvan<br>