2009/9/2 Steve
On Tue, 2009-09-01 at 08:45 +0400, Eugene Kirpichov wrote:
Hm, on my machine Don's code has exactly the same performance my code above. That's strange.
Also, replacing the 'test' and 'parse' functions with this one
add :: Int -> Int -> S.ByteString -> Int add k i s = fst $ S.foldl' f (i, 0) s where f (!i, !n) '\n' | n`divisibleBy`k = (i+1, 0) | otherwise = (i, 0) f (!i, !n) w = (i, 10*n+ord w-ord '0')
increases performance by another 15% (0.675s vs 0.790s)
On my system I get a 50% slowdown using this add function!
I guess is just shows that benchmarking code on one single CPU/memory/OS/ghc combination does not give results that apply widely. I'm using: AMD Athlon X2 4800 2GB memory Linux (Fedora 11, 64-bit version) ghc 6.10.3
I've got a Centrino Duo 2000 (I'm on a notebook), Ubuntu 9.04 and ghc 6.10.2. However, we have not set up on what exact input file we're using :) I'm using one where it is written "10000000 3" and then 10000000 lines of "999999999" follow. Also, I wonder what one'd get if one compiled this program with jhc, but I don't know whether jhc is able to compile Data.ByteString.
Steve
-- Eugene Kirpichov Web IR developer, market.yandex.ru