On Thu, May 13, 2010 at 10:51 AM, wren ng thornton
Andrea Vezzosi wrote:
wren ng thornton wrote:
With this change [1] I can't notice any difference for your benchmark[2]. Then again, all the runTest calls take 0 msec and I've had no luck making the computation take much time; perhaps your computer can detect a difference.
On my machine, with ghc-6.12.1, yours and the original ErrCPS give quite similar results, both ~2x slower than Either. However it's important to note that these results are highly dependent on the monadic expressions being evaluated, with a different benchmark you can get an huge speedup with the CPS versions.
That's very curious. After installing Criterion, my machine (OSX 10.5.8 2.8GHz Intel Core2Duo, GHC 6.12.1 with -O2) shows only 1% difference between my ErrCPS and Either on this benchmark. Alas, I can't print kernel density graphs since Crieterion charts are broken on 6.12. It seems buggy that your platform would behave so much differently...
I got the measurements from the original code, could you share the code that uses criterion instead?
mkEMA is in fact quite peculiar, since there's no catchError and the throwError call is rarely (or never?) made, and thanks to foldM you get that (>>=) is only used in a right associated way, which is the ideal situation for Either.
Indeed, mkEMA is a sort of worst-case comparison that doesn't take advantage of the ability to short-circuit.
-- Live well, ~wren _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe