[Haskell-cafe] Need help - my haskell code is over 50 times slower than equivalent perl implementation

[Carter Schonwald]

use mapM

you've got

mapMI :: (a -> IO b) -> [a] -> IO [b]
mapMI _ [] 	= return []
mapMI f (x:xs) 	= do y <- SIU.unsafeInterleaveIO (f x) ; ys <-
SIU.unsafeInterleaveIO (mapMI f xs) ; return (y:ys)


in your code, and thats going to make you sad


On Tue, Jun 24, 2014 at 12:08 PM, C K Kashyap <ckkashyap at gmail.com> wrote:

> Dear cafe,
>
> I have created a reproducible app here -
> https://github.com/ckkashyap/haskell-perf-repro
>
> Essentially I am trying to open a number of files and printing out their
> sized by reading them in and computing it's length.
>
> I have the equivalent perl program also there. I'd appreciate it very much
> if someone could take a look at my Haskell implementation and point out
> what I am doing wrong. Since it's over 50 times slower than the perl code,
> I assume I am doing something obviously incorrect.
>
> Regards,
> Kashyap
>
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