Hello, communion people! I have a little problem and ask for an advice. I'm trying to estimate the performance speed of one pure function, but get some strange results. ------------------------------------- import qualified module Data.ByteString.Lazy.Char8 as L8 import module Data.Digest.Pure.MD5 import module System.IO.Unsafe import module System.Time import module System.Random import module Data.Char clockTime2Tuple (TOD sec pic) = (sec, pic) getClockTimeTuple = getClockTime >>= (\ x -> return $ clockTime2Tuple x) subTimeTuples (s2,ps2) (s1,ps1) = let dps = ps2-ps1 in let (s,ps) = (s2-s1-(if dps<0 then 1 else 0), if dps<0 then dps+(10^12) else dps) in (s, (div) ps (10^6)) test_md5 test_input n = flip mapM test_input ( \ input_row -> do t1 <- getClockTimeTuple sequence_ (replicate n (return $ md5 input_row)) t2 <- getClockTimeTuple dt <- subTimeTuples t2 t1 return (dt) ) test_list = [ pack "Hello world!"] ++ [L8.replicate 1000000 ':'] ------------------------------------- The results are (iterations_count, microseconds): (1000, [105,105]) (+/- 10) (10000, [1000,950]) (+/- 50) (100000, [9050,9000]) (+/- 50) (1000000, [89200,89150]) (+/- 100) ------------------------------------- I suspect following problems, which make the results non-objective: 1. I cant get out of laziness 2. I don't turn off GHC internal optimizers So, perhaps, GHC evaluates the MD5 once, but cycles on something else?.. For now I can only guess. Could anybody, please clarify and maybe suggest configuration, which would allow objective speed estimation? Thanks in advance, Best regards, Belka -- View this message in context: http://www.nabble.com/estimating-the-speed-of-operation-tp22075843p22075843.... Sent from the Haskell - Haskell-Cafe mailing list archive at Nabble.com.