A String is a [Char] and a Char is a heap object. So a file represented as a string takes a massive 20 bytes/char (12 for the cons cell, 8 for the Char cell). Then it's all sucked through several functions. It's entirely possible, though, that the biggest performance hit is in the I/O itself. We'd be happy if anyone wanted to invesigate and improve. Simon | -----Original Message----- | From: John Atwood [mailto:atwoodj@cs.orst.edu] | Sent: 02 March 2001 01:12 | To: Josef Svenningsson | Cc: glasgow-haskell-users@haskell.org | Subject: Bagley shootout. Was: Lightningspeed haskell | | | I notice that the reverse file program, while concise, is quite slow. | The program in its entirety is: | main = interact $ unlines . reverse . lines | | Any thoughts on why its time is 5.68 seconds, vs 3.56 for tcl, 2 for | perl, 0.19 for gcc, 0.18 for ocaml; and how it might be sped | up? Is the | lack of speed all in the stdio I/O? | | Is there a way to tell which benchmarks have no haskell entry? | | John Atwood | -- | | Josef Svenningsson wrote: | > | > Hi all. | > | > Some days ago someone posted this url: | > http://www.bagley.org/~doug/shootout/ | > | > which is a page benchmarking a number of different languages and | > compilers where ghc is one of them. Some benchmarks lacked a haskell | > versions (and some still do) and so I decided to fill in | some of the gaps. | > | > One benchmark turned out to give pretty remarkable results. It's the | > producer/consumer benchmark. I suggest you all take a look | at it. The | > haskell version is six (SIX!!!) times faster than the c | version. Hey, | > what's going on here? I would really like to hear some | comments from our | > dear implementors. | > | > It should be noted that synchronisation is achieved by using | > slightly different kinds of primitives. But still... six times... | > | > I lift my hat of for the ghc-implementors. | > | > /Josef | > | > | > _______________________________________________ | > Glasgow-haskell-users mailing list | > Glasgow-haskell-users@haskell.org | > http://www.haskell.org/mailman/listinfo/glasgow-haskell-users | > | | | _______________________________________________ | Glasgow-haskell-users mailing list | Glasgow-haskell-users@haskell.org | http://www.haskell.org/mailman/listinfo/glasgow-haskell-users |