Superlinear speedup can occur due to the increased cache size.
24.12.2011, в 19:49, Burak Ekici <ekcbu...@hotmail.com> написал(а): > Dear List, > > I am trying to parallelize Karatsuba multiplication with Haskell's > second generation strategies. Although, I am running the code on an > Intel quad-core CPU, I abnormally have a speedup much greater > than 4, around 10, which means a weird parallelization or something > occurs. > > I would be appreciated, if anyone make some comments on the issue > explaining the possible reasons why this weird incident occurs? > > Here is the basic parallel portion of the code: > > karatsuba :: Int -> [Bool] -> [Bool] -> [Bool] > karatsuba _ [] _ = [] > karatsuba _ _ [] = [] > karatsuba currentDepth xs ys > | (l < 32 || currentDepth >= limit) = mul xs ys > | otherwise = (x `add` (replicate l False ++ (z `add` (replicate l False ++ > y)))) `Main.using` strategy > where > l = (min (length xs) (length ys)) `div` 2 > (xs0, xs1) = splitAt l xs > (ys0, ys1) = splitAt l ys > x = (normalize (karatsuba (currentDepth+1) xs0 ys0)) > y = (normalize (karatsuba (currentDepth+1) xs1 ys1)) > z = ((karatsuba (currentDepth+1) (add xs0 xs1) (add ys0 ys1)) `sub` > (normalize (karatsuba (currentDepth+1) xs0 ys0)) `sub` (normalize (karatsuba > (currentDepth+1) xs1 ys1))) > strategy res = do (Main.rpar) (x) > (Main.rpar) (y) > (Main.rpar) (z) > Main.rdeepseq res > > Many thanks in advance and kind regards. > > Saluti, > Burak. > > > > > _______________________________________________ > Haskell-Cafe mailing list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe
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