Re: [Haskell-cafe] Is Haskell IO inherently slower than C?

4 May 2016


      I also tried the more standard forM_ [0..100000] idiom and got similar
times. I hoped loop might be faster, but apparently not.

On Wed, May 4, 2016 at 9:05 PM Jake  wrote:
...
I'm trying to write a program in Haskell that writes a large file at the
end, and it seems like that output alone is taking way longer than it
should. I don't understand why Haskell shouldn't be able to write data as
quickly as C, so I wrote two test files:
-- Test.hs
import Control.Loop
import Data.ByteString.Builder
import System.IO
main :: IO ()
main =
  numLoop 0 1000000 $ \_ ->
    hPutBuilder stdout $ char7 ' '
// test.c
#include 
int main() {
  int i;
  for (i = 0; i < 1000000; i++) {
    fprintf(stdout, " ");
  }
  return 0;
}
I compiled them both with -O2, and ran them redirecting their outputs to
/dev/null. For the Haskell version I got times aroudn 0.3 seconds, while
the C version was around 0.03. Is there any reason why in simple IO the
Haskell version would be slower by an order of magnitude?