RE: [Haskell-cafe] x86 code generation going wrong?

From: Chris Kuklewicz To: haskell-cafe@haskell.org Subject: [Haskell-cafe] x86 code generation going wrong? Date: Sat, 07 Jan 2006 16:18:59 +0000

Hello,

I need to ask for some help to test x86 code generation.

There is a factor of two runtime difference between the code I am benchmarking on my OS X powerbook G4 (ghc 6.4.1) and shootout's speed on a linux x86 machine (ghc 6.4.1).

Could someone else running on x86 test the three versions pasted below before I think about submitting another one to the shootout?

Here are the tests on P4 2.4 ghz and athlon 64 3000 linux test1-3 in respective order of appearance (note:OPTIONS didn't do anything I have to compile -O2 -fglasgow-exts explicitely, because I've got compile error for test3.hs ) [bmaxa@maxa ~/haskell/myhaskell] $ time ./test1 < sum-file-test-input 4000000 real 0m3.550s user 0m3.440s sys 0m0.080s [bmaxa@maxa ~/haskell/myhaskell] $ time ./test2 < sum-file-test-input 4000000 real 0m3.708s user 0m3.660s sys 0m0.060s [bmaxa@maxa ~/haskell/myhaskell] $ time ./test3 < sum-file-test-input 4000000 real 0m3.678s user 0m3.620s sys 0m0.050s This is on athlon64 3000 , linux : [bmaxa@devel64 ~]$ time ./test1 < sum-file-test-input 4000000 real 0m5.782s user 0m5.724s sys 0m0.056s [bmaxa@devel64 ~]$ time ./test2 < sum-file-test-input 4000000 real 0m5.953s user 0m5.900s sys 0m0.052s [bmaxa@devel64 ~]$ time ./test3 < sum-file-test-input 4000000 real 0m5.403s user 0m5.332s sys 0m0.072s Greetings, Bane.

To compile "ghc --make filename.hs -o program"

To run "cat input-file | time ./program"

where to save space, the gzip'd input file is at

http://paradosso.mit.edu/~ckuklewicz/sum-file-test-input.gz

------------------------------------------------------------------------- -- Original version {-# OPTIONS -O2 #-} import Char( ord )

main :: IO () main = getContents >>= print . accP 0 0

accP :: Int -> Int -> String -> Int accP before this [] = before+this accP before this ('\n':xs) = accP (before+this) 0 xs accP before this ('-' :xs) = accN before this xs accP before this (x :xs) = accP before (this*10+ord(x)-ord('0')) xs

accN :: Int -> Int -> String -> Int accN before this [] = before-this accN before this ('\n':xs) = accP (before-this) 0 xs accN before this (x :xs) = accN before (this*10+ord(x)-ord('0')) xs

------------------------------------------------------------------------- -- Faster on G4, 2x slower on x86 {-# OPTIONS -O2 -funbox-strict-fields #-} import GHC.Base

data I = I !Int

main = print . new (I 0) =<< getContents

new (I i) [] = i new (I i) ('-':xs) = neg (I 0) xs where neg (I n) ('\n':xs) = new (I (i - n)) xs neg (I n) (x :xs) = neg (I (parse x + (10 * n))) xs new (I i) (x:xs) = pos (I (parse x)) xs where pos (I n) ('\n':xs) = new (I (i + n)) xs pos (I n) (x :xs) = pos (I (parse x + (10 * n))) xs

parse c = ord c - ord '0'

------------------------------------------------------------------------- -- Explicitly unboxed proposal, faster on G4 {-# OPTIONS -fglasgow-exts -O2 #-}

import GHC.Base

main = print . sumFile =<< getContents where sumFile = (\rest -> newLine rest 0#)

newLine [] rt = (I# rt) newLine ('-':rest) rt = negLine rest 0# where negLine ('\n':rest) soFar = newLine rest (rt -# soFar) negLine ( x :rest) soFar = negLine rest (d2i x +# (10# *# soFar)) newLine (x:rest) rt = posLine rest (d2i x) where posLine ('\n':rest) soFar = newLine rest (rt +# soFar) posLine ( x :rest) soFar = posLine rest (d2i x +# (10# *# soFar))

d2i (C# c) = (ord# c) -# z where z = ord# '0'# -------------------------------------------------------------------------

Thanks, Chris

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