On Tue, Oct 28, 2008 at 5:43 PM, Don Stewart <[EMAIL PROTECTED]> wrote: > jwlato: >> Hello, >> >> I was experimenting with using ghc-6.10.0.20081007 on a project, and >> it seems that binary-0.4.3.1 has markedly worse performance in certain >> cases. With the following simple test: >> >> > import qualified Data.ByteString.Lazy as L >> > import Data.Binary >> > import Data.Binary.Get >> > import Control.Monad >> > >> > main :: IO () >> > main = do >> > b <- L.readFile "some_binary_file" >> > putStrLn $ show $ runGet getter b >> >> > getter :: Get [Word16] >> > getter = replicateM 1000000 getWord16le >> >> running this program compiled with ghc-6.10 takes about 4 times as >> long (and consumes much more memory) as when compiled with ghc-6.8.3. >> The extra time appears to be proportional to the number of elements >> processed in the Get. Running the programs with -hT shows a clear >> memory difference, which I think is the source of the problem. I've >> placed pdfs of that output at https://webspace.utexas.edu/latojw/data/ >> >> The difference seems to manifest itself only when the elements are >> actually processed; changing "show $ runGet " to "show $ length $ >> runGet " is slightly faster in 6.10. >> >> I was working on an Intel Mac with OS 10.4, binary-0.4.3.1, and >> bytestring-0.9.1.4. Can anyone confirm this, or suggest what might be >> the difference? >> > > Is this the sole test case? > > I can investigate. Though perhaps using a newer GHC release candidate is > also a good idea. > > -- Don >
I'll try a newer release candidate, although at the time I first ran this it was the latest. Last night I tried creating the bytestring using "repeat 1" to remove the file I/O, and the result was the same. There are a few other things I want to try as well (removing replicateM, folding the list to force values rather than printing them all), but my time is extremely limited at the moment. John _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
