[Haskell-cafe] Unable to get parallelism using `par`

Daniel Fischer daniel.is.fischer at googlemail.com
Thu Feb 17 17:32:43 CET 2011

On Thursday 17 February 2011 17:02:55, C K Kashyap wrote:
> Hi,
> I tried the first example from "A tutorial on Parallel and Concurrent
> programming in Haskell" but I cant seem to get sparks to get converted
> to OS threads.
> Below is the program I am using.
> I did ghc --make -threaded program.hs
> then
> ./program +RTS -N2
> I don't see any speed gain compared to N1.
> Am I missing something?

Hmm, using parSumFibEuler instead of sumFibEuler, I get > 100% CPU usage 
(close to 200% if I adjust parameters so both computations take 
approximately the same time).
Works for me, then.

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