ghc and signal processing

[Simon Peyton-Jones]

I think the HEAD goes just as fast as 6.2 now.

Simon

| -----Original Message-----
| From: glasgow-haskell-users-bounces at haskell.org
[mailto:glasgow-haskell-users-
| bounces at haskell.org] On Behalf Of Jeremy Shaw
| Sent: 24 February 2004 04:04
| To: glasgow-haskell-users at haskell.org
| Subject: Re: ghc and signal processing
| 
| Hrm,
| 
| Okay, it seems that my problems maybe be due to using ghc 6.3.
| 
| Here are the results of running test under different compiler versions
| (see end of message for code):
| 
| 
| Athlon 600MHz + FreeBSD + GHC 6.0.1
| 
| real    0m0.414s
| user    0m0.361s
| sys     0m0.016s
| 
| Athlon 600MHz + FreeBSD + GHC 6.3 (built from CVS HEAD on Feb 15,
2004)
| 
| real    0m2.517s
| user    0m2.289s
| sys     0m0.069s
| 
| Pentium III 1.13GHz + Debian + GHC 6.2
| 
| real    0m0.305s
| user    0m0.196s
| sys     0m0.027s
| 
| Pentium III 1.13GHz + Debian + GHC 6.3 (built from CVS HEAD on Feb 1,
2004)
| 
| 
| real    0m1.302s
| user    0m1.196s
| sys     0m0.044s
| 
| 
| So it seems like maybe GHC 6.3's performance for this particular test
| is around 3-5 slower?
| 
| Jeremy Shaw.
| 
| 
| module Main where
| 
| import Data.Array
| import Data.Array.IO
| 
| import System.IO
| 
| main = do h <- openFile "test.b" WriteMode
| 	  a <- newArray_ (1,1800000)
| 	  b <- mapArray id a
| 	  c <- mapArray id b
| 	  hPutArray h c 1800000
| 
| 
| At Mon, 23 Feb 2004 13:37:45 -0800,
| Mike Gunter wrote:
| >
| >
| > Hmmm.  With -O2 on GHC 6.2, I get 0.177s, 0.217s, and 0.348s for
your
| > three Haskell examples and 0.187s (with gcc -O2) for your C example.
| > The output of -ddump-simpl for the looks perfect for the second
| > Haskell example.  My GHC seems to be doing a bang-up job here.
What's
| > wrong with yours?  (For the third example GHC's code could be
improved
| > by additional inlining or hoisting of a constant array outside of
the
| > loop.)
| >
| > 	mike
| >
| _______________________________________________
| Glasgow-haskell-users mailing list
| Glasgow-haskell-users at haskell.org
| http://www.haskell.org/mailman/listinfo/glasgow-haskell-users