2011/9/24 Burak Ekici
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.
Thanks a lot, Burak.
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