Re: Floating point performance
"Julian Seward (Intl Vendor)" wrote: I tried this, with ghc-4.08.1 -O both with and without profiling, on a Sparc box of I believe around 300 MHz, and I can't reproduce it at all. Without profiling, it allocates about 505 k of heap and runs in 0.02 seconds. Ummm ? J I didn't use any optimizations, but I am sure that passing -O to ghc will make it see that 1*1*... is a constant expression. I guess turning all optimizations off is not the right way to test stuff either. Jan ___ Glasgow-haskell-users mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: Floating point performance
Mon, 29 Jan 2001 18:15:02 +0100, Jan Kort [EMAIL PROTECTED] pisze:
I didn't use any optimizations, but I am sure that
passing -O to ghc will make it see that 1*1*... is a
constant expression.
It does not, because it's n*1*1*1*... where n is not a constant.
Major advantages seem to be from the strictness analysis.
--
__(" Marcin Kowalczyk * [EMAIL PROTECTED] http://qrczak.ids.net.pl/
\__/
^^ SYGNATURA ZASTPCZA
QRCZAK
___
Glasgow-haskell-users mailing list
[EMAIL PROTECTED]
http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
RE: Floating point performance
Fri, 26 Jan 2001 17:40:17 +0100, Jan Kort [EMAIL PROTECTED] pisze: I made a profile and it says most of the time (93%) is spent in the function bar. Did you compile with optimization turned on (option -O)? I see similar results without -O but quite different with -O. Without optimisation, you get the native code generator which produces particularly brain-dead code for floating point on x86 (mainly due to Intel's brain-dead design of the x86 floating point unit). With optimisation, you get gcc. Cheers, Simon ___ Glasgow-haskell-users mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Floating point performance
Hi, I noticed ghc (version 4.08.1) floating point performance is really slow on my computer: a 270Mhz sun ultra5. The program below does 1 milion floating point multiplications and takes 2 seconds to run. I made a profile and it says most of the time (93%) is spent in the function bar. Any idea what is going on ? Regards, Jan module Main where foo :: Double - [Double] foo 0 = [1] foo n = bar n:foo (n-1) bar :: Double - Double bar n = n*1*1*1*1*1*1*1*1*1*1 *1*1*1*1*1*1*1*1*1*1 *1*1*1*1*1*1*1*1*1*1 *1*1*1*1*1*1*1*1*1*1 *1*1*1*1*1*1*1*1*1*1 *1*1*1*1*1*1*1*1*1*1 *1*1*1*1*1*1*1*1*1*1 *1*1*1*1*1*1*1*1*1*1 *1*1*1*1*1*1*1*1*1*1 *1*1*1*1*1*1*1*1*1*1 foldl' :: (a - b - a) - a - [b] - a foldl' _ a [] = a foldl' f a (x:xs) = (foldl' f $! f a x) xs main :: IO() main = putStrLn (show (foldl' (+) 0 (foo 1))) --- Profile: total time =2.60 secs (130 ticks @ 20 ms) total alloc = 24,845,828 bytes (excludes profiling overheads) COST CENTRE MODULE %time %alloc bar Main93.1 96.1 foo Main 3.12.4 foldl' Main 3.11.4 individual inherited COST CENTRE MODULE entries %time %alloc %time %alloc MAIN MAIN 00.0 0.0100.0 100.0 mainMain 00.0 0.0 0.0 0.0 CAF PrelShow 10.0 0.0 0.0 0.0 CAF PrelFloat30.0 0.0 0.0 0.0 CAF PrelHandle 30.0 0.0 0.0 0.0 CAF Main 90.0 0.0100.0 100.0 main Main 10.8 0.0100.0 100.0 foo Main 100013.1 2.4 96.2 98.5 bar Main 1 93.1 96.1 93.1 96.1 foldl'Main 100023.1 1.4 3.1 1.4 ___ Glasgow-haskell-users mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: Floating point performance
Fri, 26 Jan 2001 17:40:17 +0100, Jan Kort [EMAIL PROTECTED] pisze:
I made a profile and it says most of the time (93%) is spent in
the function bar.
Did you compile with optimization turned on (option -O)?
I see similar results without -O but quite different with -O.
--
__(" Marcin Kowalczyk * [EMAIL PROTECTED] http://qrczak.ids.net.pl/
\__/
^^ SYGNATURA ZASTPCZA
QRCZAK
___
Glasgow-haskell-users mailing list
[EMAIL PROTECTED]
http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
