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Today's Topics:
1. Re: Diagnosing : Large memory usage + low CPU (Edward Z. Yang)
2. FFI export lazy list of string (Alexander.Vladislav.Popov )
3. Compiling shared (dll) library (Alexander.Vladislav.Popov )
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Message: 1
Date: Mon, 05 Dec 2011 01:29:17 -0500
From: "Edward Z. Yang" <[email protected]>
Subject: Re: [Haskell-beginners] Diagnosing : Large memory usage + low
CPU
To: Hugo Ferreira <[email protected]>
Cc: beginners <[email protected]>
Message-ID: <1323066469-sup-4667@ezyang>
Content-Type: text/plain; charset=UTF-8
Excerpts from Hugo Ferreira's message of Fri Dec 02 05:57:00 -0500 2011:
> I have attached a profiling session (showing types).
> I am surprised to see that the "[]" consumes so much data.
> Where is this coming from? Need to analyse this more closely.
For an -hT profile, what that actually means is your lists are using lots
of memory.
> Any idea how I can track what's generating all those "[]" ?
> Note that the (,,) seems to be the NGramTag. data which is basically
> used as a list (Zipper).
For that, I recommend rebuilding with profiling and use the RTS flag -hc.
For more details on how to profile programs like this, check out:
http://blog.ezyang.com/2011/06/pinpointing-space-leaks-in-big-programs/
Edward
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Message: 2
Date: Mon, 5 Dec 2011 14:08:59 +0600
From: "Alexander.Vladislav.Popov "
<[email protected]>
Subject: [Haskell-beginners] FFI export lazy list of string
To: [email protected]
Message-ID:
<calpbq9aylhmu4yh2wuda9-ykxyhw25czcbcovon8hn+-oqu...@mail.gmail.com>
Content-Type: text/plain; charset="utf-8"
Hi, Haskellers.
Advise me please, how I can export lazy and potentially infinite list of
string from Haskell program. I think I must call it iteratively: the first
call initiate some structure and other calls iterate over it, something
like pair of function `find_first' and `find_next'. And how to marshall
this structure between programs. Or think in a wrong way? Does any example
exist how I can make it?
Alexander Popov
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Message: 3
Date: Mon, 5 Dec 2011 16:39:06 +0600
From: "Alexander.Vladislav.Popov "
<[email protected]>
Subject: [Haskell-beginners] Compiling shared (dll) library
To: [email protected]
Message-ID:
<CALpbQ9biEiK4am0UyZQpuOgrqiWfNd4PRmme+BDabj_hqYLx=a...@mail.gmail.com>
Content-Type: text/plain; charset="utf-8"
Hi, Haskellers.
I'm trying to compile following program (where Regex.Genex is a package
what I need to produce all possible expresions by the given pattern and
`adder' is just FFI sample):
-- genexlib.hs
{-# LANGUAGE BangPatterns, ForeignFunctionInterface #-}
module GenexLib where
import Regex.Genex
import System.IO
import System.Environment
adder :: Int -> Int -> IO Int -- gratuitous use of IO
adder x y = return (x+y)
foreign export stdcall adder :: Int -> Int -> IO Int
-- genexlib.hs end
// start.c
#include <Rts.h>
void HsStart()
{
int argc = 1;
char* argv[] = {"ghcDll", NULL}; // argv must end with NULL
// Initialize Haskell runtime
char** args = argv;
hs_init(&argc, &args);
}
void HsEnd()
{
hs_exit();
}
// start.c end
I'm using ghc
>ghc --version
The Glorious Glasgow Haskell Compilation System, version 7.0.2
compiling:
>ghc -c genexlib.hs
>ghc -c start.c
>ghc -shared -o genexlib.dll genexlib.o genexlib_stub.o start.o
genexlib.o:fake:(.text+0xd1): undefined reference to
`__stginit_regexzmgenexzm0zi3zi2_RegexziGenex_'
Creating library file: genexlib.dll.a
collect2: ld returned 1 exit status
and get undefined reference.
But If I try to compile the executable from similar code:
-- genexlib.hs
{-# LANGUAGE BangPatterns, ForeignFunctionInterface #-}
-- module GenexLib where
import Regex.Genex
import System.IO
import System.Environment
defaultRegex :: String
defaultRegex = "a(b|c)d{2,3}e*"
main :: IO ()
main = do
hSetBuffering stdout NoBuffering
args <- getArgs
case args of
[] -> do
prog <- getProgName
if prog == "<interactive>" then run [defaultRegex] else do
fail $ "Usage: " ++ prog ++ " regex [regex...]"
rx -> run rx
run :: [String] -> IO ()
run regex = do
let s = genexPure regex
mapM_ print s
-- genexlib.hs end
>ghc --make genexlib.hs -O2
it's ok, no errors, and you can see in GHCi:
*Main> :main
"abdd"
"acdd"
"abddd"
"acddd"
"abddeee"
"acddeee"
"abdddeee"
"acdddeee"
"abddee"
"acddee"
"abdddee"
"acdddee"
"abdde"
"acdde"
"abddde"
"acddde"
Where is my mistake? What am I doing wrong?
In first case, when compiling shared dll, I tried to link libraries what
I've found in `cabal' directory (like `libHSregex-genex-0.3.2.a') to work
around errors but all in vain.
--
Alexander Popov
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