Excuse me, I read too quick.
It works for forkIO too, although I'm not sure about forkOS. I don't
have a demo around, but you can verify with the concurrency demos in
the wiki:
http://haskell.org/haskellwiki/Concurrency_demos/Zeta
If it doesn't work, perhaps you are in an unsupported platform.
Cheers
pepe
On 13/03/2007, at 18:10, Dusan Kolar wrote:
Yes, it works for operator /par/. That's what I've reported. But
should it work for forkIO and forkOS? Could anybody give more
detailed answer than yes, no? :-) (Link to the Web is OK.)
BTW, thanks for the link to the paper (moreover, I can see, that
googling over haskell.org is not sufficient ;-) ).
Regards,
Dusan
Pepe Iborra wrote:
On 13/03/2007, at 17:46, Jefferson Heard wrote:
Simon will probably chime in on it as well, but his paper on the
subject is
the best there is:
http://research.microsoft.com/~simonpj/Papers/strategies.ps.gz
It does work in GHC 6.6 very nicely.
You can try it with the following naive fib function, extracted
from the paper mentioned above:
\begin{code}
import Control.Parallel
import System.Environment
import Fib
main = do
(x:_) <- getArgs
print$ pfib (read x)
pfib 0 = 1
pfib 1 = 1
pfib n = n1 `par` n2 `seq` n1+n2+1
where (n1,n2) = (pfib(n-1), pfib(n-2))
\end{code}
pep:~/code/snippets/Parallelism$ ghc --make -O Main -threaded
pep:~/code/snippets/Parallelism$ time src/Main 33
11405773
real 0m1.444s
user 0m1.343s
sys 0m0.020s
pep:~/code/snippets/Parallelism$ time src/Main 33 +RTS -N2
11405773
real 0m0.764s
user 0m1.367s
sys 0m0.030s
Got a speedup of 100%, and didn't use threads at all. Yay!
pepe
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