[Haskell-beginners] Performance of Idiomatic lazy Haskell
markus.boehm at googlemail.com
Mon Feb 1 09:22:45 EST 2010
Daniel, here another feedback:
F:\MeineUebungen>ghc -O2 -fexcess-precision -fvia-C -optc-O3 -o luaLoop --make p
[1 of 1] Compiling Main ( p085-pi_lualoop.hs, p085-pi_lualoop.o )
Linking luaLoop.exe ...
F:\MeineUebungen>echo '0.00000001' | time ./luaLoop
Eingegebene Zeit kann nicht übernommen werden.
Geben Sie die neue Zeit ein:
F:\MeineUebungen>luaLoop +RTS -sstderr -RTS
luaLoop +RTS -sstderr
61,428 bytes allocated in the heap
1,316 bytes copied during GC
4,564 bytes maximum residency (1 sample(s))
11,820 bytes maximum slop
1 MB total memory in use (0 MB lost due to fragmentation)
Generation 0: 0 collections, 0 parallel, 0.00s, 0.00s elapsed
Generation 1: 1 collections, 0 parallel, 0.00s, 0.00s elapsed
INIT time 0.02s ( 0.00s elapsed)
MUT time 8.06s ( 16.83s elapsed)
GC time 0.00s ( 0.00s elapsed)
EXIT time 0.00s ( 0.00s elapsed)
Total time 8.08s ( 16.83s elapsed)
%GC time 0.0% (0.0% elapsed)
Alloc rate 7,604 bytes per MUT second
Productivity 99.8% of total user, 47.9% of total elapsed
On Mon, Feb 1, 2010 at 3:08 PM, Markus Böhm <markus.boehm at googlemail.com> wrote:
> Daniel, I use GHC 6.12.1 and Windows XP. The time command doesn't seem
> to work. It says in German: specified time can't be read. Give a new
> -- Markus
> On Mon, Feb 1, 2010 at 2:52 PM, Daniel Fischer <daniel.is.fischer at web.de> wrote:
>> Am Montag 01 Februar 2010 14:31:40 schrieb Markus Böhm:
>>> Daniel, with LuaJIT it needs 1.45 sec cpu-time on my machine with
>>> attached variant.
>> That's pretty fast.
>>> I compiled all our Haskell variants with ghc --make -O2.
>> Well, GHC isn't as good at loop-optimising as gcc is. Depending on the
>> loop, the via-C compiled binaries are between 1.4 and 2.3 times faster than
>> the NCG compiled.
>>> I don't know about -fvia-C, have to find out. I hope I didn't
>>> distract You with my Lua variant.
>> No sweat.
>>> In any case thank You very much for
>>> your advice. Markus.
>> You're welcome.
>> Can you try the below with
>> ghc -O2 -fexcess-precision -fvia-C -optc-O3 -o luaLoop --make Whatever.hs
>> and run with
>> echo '0.00000001' | time ./luaLoop
>> It's a fairly direct translation of the Lua code, and it runs here more or
>> less equally fast as (gcc compiled) C-loops.
>> module Main (main) where
>> main :: IO ()
>> main = do
>> putStrLn "EPS:"
>> eps <- readLn :: IO Double
>> print $ 4*calcPi eps
>> calcPi :: Double -> Double
>> calcPi eps = go False 1 3
>> go bl p1 i
>> | 4*abs(p2-p1) < eps = p1
>> | otherwise = go (not bl) p2 (i+2)
>> p2 | bl = p1+1/i
>> | otherwise = p1-1/i
More information about the Beginners