[Shootout-list] Re: ring of processes

[Tomasz Zielonka]

On Sun, Oct 03, 2004 at 03:08:49AM +0000, Aaron Denney wrote:
> Another possibility given the large heap usage is garbage-generation &
> collection.  Not quite sure what to do about that, though there's a
> chance strictness annotations could help.

Using a different implementation of 'for' allows to decrease the number
of allocations and improves time by a factor of about 2.

    for :: Int -> IO () -> IO ()
    for n x = sequence_ [x | i <- [1..n]]

( Thanks to Carsten Schultz for pointing a 'for' implementation that GHC
  handles so well )

Adding these RTS options also improves time

    +RTS -A8m -k256

BTW, -k128 makes things worse, probably bacause the initial thread stack
is too small and has to be resized.

Best regards,
Tom

-- 
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