Thanks a lot for the quick answer. Accordingly, I have just changed the code into below one, however sparks are still being pruned. Do you have any other ideas? Bests, Burak. ------ split4ToEnc :: RSAPublicKey -> [Integer] -> [Integer] split4ToEnc (PUB n e) [] = [] split4ToEnc (PUB n e) (x:xs) = ((ersa (PUB n e) secondPart2) ++ (ersa (PUB n e) secondPart1) ++ (ersa (PUB n e) firstPart2) ++ (ersa (PUB n e) firstPart1)) `using` strategy where firstPart1 = fst (Main.splitAt((length (x:xs)) `div` 4) (fst(Main.splitAt ((length (x:xs)) `div` 2) (x:xs)))) firstPart2 = snd (Main.splitAt((length (x:xs)) `div` 4) (fst(Main.splitAt ((length (x:xs)) `div` 2) (x:xs)))) secondPart1 = fst (Main.splitAt((length (x:xs)) `div` 4) (snd(Main.splitAt ((length (x:xs)) `div` 2) (x:xs)))) secondPart2 = snd (Main.splitAt((length (x:xs)) `div` 4) (snd(Main.splitAt ((length (x:xs)) `div` 2) (x:xs)))) strategy res = do (rpar `dot` rdeepseq) (ersa (PUB n e) firstPart1) (rpar `dot` rdeepseq) (ersa (PUB n e) firstPart2) (rpar `dot` rdeepseq) (ersa (PUB n e) secondPart1) (rpar `dot` rdeepseq) (ersa (PUB n e) secondPart2) rdeepseq res -----

From: aslatter@gmail.com Date: Sat, 24 Sep 2011 11:19:49 -0500 Subject: Re: [Haskell-cafe] A Missing Issue on Second Generation Strategies To: ekcburak@hotmail.com CC: haskell-cafe@haskell.org

On Sat, Sep 24, 2011 at 11:14 AM, Antoine Latter wrote:

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2011/9/24 Burak Ekici :

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Dear List,

I am trying to parallelize RSA encryption and decryption by using below manner, but when I run executable output file with "+RTS -s -N2" command on Windows 7, output stats say 4 sparks are being created however none of them converted into real OS threads.

-- SPARKS :4 (0 converted, 4 pruned) --

I was thinking that the problem could occur due to lack of forcing parallelization but, as far as I know 'rdeepseq' works for that aim.

Briefly, I could not solve the issue why parallelization was not being implemented. I would be appreciated if any of you shed a light on the issue that I missed.

Here is the mentioned part of code:

split4ToEnc :: RSAPublicKey -> [Integer] -> [Integer] split4ToEnc (PUB n e) [] = [] split4ToEnc (PUB n e) (x:xs) = ((ersa (PUB n e) secondPart2) ++ (ersa (PUB n e) secondPart1) ++ (ersa (PUB n e) firstPart2) ++ (ersa (PUB n e) firstPart1)) `using` strategy where firstPart1 = fst (Main.splitAt((length (x:xs)) `div` 4) (fst(Main.splitAt ((length (x:xs)) `div` 2) (x:xs)))) firstPart2 = snd (Main.splitAt((length (x:xs)) `div` 4) (fst(Main.splitAt ((length (x:xs)) `div` 2) (x:xs)))) secondPart1 = fst (Main.splitAt((length (x:xs)) `div` 4) (snd(Main.splitAt ((length (x:xs)) `div` 2) (x:xs)))) secondPart2 = snd (Main.splitAt((length (x:xs)) `div` 4) (snd(Main.splitAt ((length (x:xs)) `div` 2) (x:xs)))) strategy res = do a <- rpar (ersa (PUB n e) (firstPart1) `using` rdeepseq) b <- rpar (ersa (PUB n e) (firstPart2) `using` rdeepseq) c <- rpar (ersa (PUB n e) (secondPart1) `using` rdeepseq) d <- rpar (ersa (PUB n e) (secondPart2) `using` rdeepseq) rdeepseq res

This isn't an area I'm expert in, but your strategy looks off to me - since you're not using 'a', 'b', 'c' and 'd' anywhere, it would make sense that you're not seeing much speedup. Also, the strategy doesn't seem to be doing anything with it's input, which looks different from most of the examples I've seen.

In summary, your strategy doesn't appear to have anything relating it to the computation you're doing with the `using`, if that makes any sense.

May a better way to phrase things is that your strategy never does anything to its input (like force any parts of it to evaluate), it merely sparks of computations that no one ever looks at. Which is why they get pruned.

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Thanks a lot, Burak.

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