I'm happy to finally release unagi-chan, an implementation of high-performance concurrent FIFO queues that have an API very similar to Control.Concurrent.Chan. You can see benchmarks and documentation here: http://hackage.haskell.org/package/unagi-chan If you have a moment (especially if you're on a non-x86 architecture) please take 10 minutes and run the tests with: $ cabal configure --enable-tests $ cabal build $ time ./dist/build/test/test Thanks to Ryan Newton for helping answer some low-level questions about his atomic-primops package which provides the CAS and fetch-and-add implementations that are the core of unagi-chan. REQUEST FOR FEEDBACK: would anyone be interested in any functionality like the following: - concurrent builder for Text, something like: new :: IO (InTextChan , Lazy.Text) write :: String -> InTextChan -> IO () - something similar for ByteString (is there a class for types convertable to ByteString?) - concurrent Text and/or ByteString readers, something like: reader :: Text -> IO TextReader takeText :: Int -> TextReader -> IO Text That's very sketchy, but I ask because I'm very close to that already with Unagi.Unboxed, and should be able to implement something like any of the above without too much trouble if it would be useful. Brandon http://brandon.si