Performance Tests in Haskell
Andreas.Schroeder at gillardon.de
Andreas.Schroeder at gillardon.de
Thu Oct 16 12:26:11 EDT 2003
Hi all,
i have changed the compilation flags and the codes as you said.
It seems to me that it worked, since the runtime of my test stabilized at
2002ns. Before, i got sometimes 4004ns.
The bigger runtime part is now (as far as i can guess, see below why) the
screen output.
That brings me to two issues for performance tests in Haskell:
1. how can i do performance tests if the tests are small? In imperative
languages, you cycle through 1000 times and divide the runtime by 1000.
How can i do something similar in haskell?
2. How do i get haskell to do something _without_ printing anything on the
screen? For now, i do something like
main = do
startt <- getCPUTime
putStr $ (show testAIBD1) ++ ", " ++ (show testZins1)
endt <- getCPUTime
putStr $ "\tTook " ++ (show $ (endt - startt) `div` ((10^6) * 5)) ++ "
ns\n"
where testAIBD1 is a sum of 40 calculation results and also is testZins1.
Another issue: with foreign C calls i have the problem to link
automatically.
i type something like
> ghc --make Main.hs -fglasgow-exts -O2 -fliberate-case-threshold100
-funbox-strict-fields -fvia-C
while having compiled the external C HAIBDUtil.c with HAIBDUtil.h to
HAIBDUtil.o. As result, i get
Chasing modules from: Main.hs
Compiling AIBD ( AIBD.hs, ./AIBD.o )
Compiling Main ( Main.hs, ./Main.o )
Linking ...
AIBD.o(.text+0x11e0):ghc1052.hc: undefined reference to `caibd'
shure, "caibd" is the called C procedure from AIBD.
well then, i type
> ghc Main.o AIBD.o HAIBDUtil.o -o HAIBD.exe
then everything is fine, and i get my executable.
Now i wanted to profile, and added the options "-prof --auto-all" to the
first ghc command.
When trying to link, i get lot's of undefined references:
> ghc Main.o AIBD.o HAIBDUtil.o -o HAIBD.exe
AIBD.o(.text+0x425):ghc1364.hc: undefined reference to `CC_LIST'
AIBD.o(.text+0x430):ghc1364.hc: undefined reference to `CC_LIST'
AIBD.o(.text+0x439):ghc1364.hc: undefined reference to `CC_ID'
AIBD.o(.text+0x444):ghc1364.hc: undefined reference to `CC_ID'
(...)
AIBD.o(.text+0x5fc):ghc1364.hc: undefined reference to `CCCS'
AIBD.o(.text+0x605):ghc1364.hc: undefined reference to `CCCS'
AIBD.o(.text+0x626):ghc1364.hc: undefined reference to `PushCostCentre'
(...)
Obviously (see "PushCostCentre" as last misssing reference),
something for profiling is missing. What is it?
Regards,
Andreas Schroeder
|---------+----------------------------------------->
| | Andreas.Schroeder at gillardon.de|
| | Gesendet von: |
| | glasgow-haskell-users-bounces@|
| | haskell.org |
| | |
| | |
| | 16.10.2003 09:37 |
| | |
|---------+----------------------------------------->
>-------------------------------------------------------------------------------------------------------------------|
| |
| An: glasgow-haskell-users at haskell.org |
| Kopie: chak at cse.unsw.edu.au |
| Thema: Re: GHC with MS .Net 2003 C compiler |
>-------------------------------------------------------------------------------------------------------------------|
Hi all, hi Manuel,
thanks for the help. Yes, i read the user docs for "earlier, faster,
thriftier, smaller ..." or a permutation of this,
but i do not _really_ remember from my university time what strict
functions are. Is by strict meant as in Formal OO that
a function is trict iff its result is _|_ iff any of its arguments is _|_ ?
I will try to use
data Genauigkeit = Absolut {wert, intervall :: !Double}
| Intervall !Double
is that what you meant? I will read the strictness flag documentation.
Thanks for the hints.
Regards,
Andreas Schroeder
|---------+----------------------------------------->
| | Manuel M T Chakravarty |
| | <chak at cse.unsw.edu.au> |
| | Gesendet von: |
| | glasgow-haskell-users-bounces@|
| | haskell.org |
| | |
| | |
| | 16.10.2003 07:02 |
| | Bitte antworten an chak |
| | |
|---------+----------------------------------------->
>
-------------------------------------------------------------------------------------------------------------------|
|
|
| An: Andreas.Schroeder at gillardon.de
|
| Kopie: glasgow-haskell-users at haskell.org
|
| Thema: Re: GHC with MS .Net 2003 C compiler
|
>
-------------------------------------------------------------------------------------------------------------------|
Andreas.Schroeder at gillardon.de wrote,
Generally, did you look at
http://haskell.org/ghc/docs/latest/html/users_guide/faster.html
> module AIBD(aibd, rechneZins, rechneRate, rechneKapital) where
> import Foreign(unsafePerformIO)
>
> type Funktion = Double -> Double
>
> data Genauigkeit = Absolut {wert, intervall :: Double}
> | Intervall Double
See the paragraph under "Use strictness annotations" on the
above web page on how to use strictness annotations to speed
this data type up.
> istOk :: Genauigkeit -> Double -> Double -> Bool
> istOk (Absolut w i) x _ = abs (x-w) <= i
> istOk (Intervall i) _ dx = abs dx <= i
>
> sekantenVerfahren :: Funktion -> Genauigkeit -> Genauigkeit -> Int ->
> Double -> Double
> sekantenVerfahren f gx gy tiefe start = sekantenIter f tiefe gx gy x1 x2
y1
> y2 where
> x1 = start
> x2 = start + start * 0.1
> y1 = f x1
> y2 = f x2
> sekantenIter _ 0 _ _ _ x2 _ _ = x2
> sekantenIter f tiefe gx gy x1 x2 y1 y2 =
> let
> x3 = x2 - y2 * (x2 - x1) / (y2 - y1)
> y3 = f x3
> dy = y3 - y2
> dx = x3 - x2
> in
> if (istOk gx x3 dx) && (istOk gy y3 dy) then x3
> else sekantenIter f (tiefe-1) gx gy x2 x3 y2 y3
Code like this may benefit from using the option "-O2" and
possibly also "-fliberate-case-threshold100"
http://haskell.org/ghc/docs/latest/html/users_guide/flag-reference.html#AEN5918
> foreign import ccall "HAIBDUtil.h caibd" caibd :: Double -> Double ->
> Double -> Int -> IO Double
>
> aibd:: Double -> Double -> Double -> Int -> Double
> aibd kapital zins rate jahre = unsafePerformIO (caibd kapital zins rate
> jahre)
> {-
> does the same than
> aibd:: Double -> Double -> Double -> Int -> Double
> aibd kapital _ _ 0 = kapital
> aibd kapital zins rate jahre = aibd (kapital + kapital * zins - rate)
> zins rate (jahre-1)
> -}
Two comments with
-O2 -fliberate-case-threshold100
the Haskell version may be as fast as the C version. If
not, better foreign import as a pure functions
foreign import ccall "HAIBDUtil.h caibd" caibd :: Double -> Double ->
Double -> Int -> Double
and omit the unsafePerformIO.
Cheers,
Manuel
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