[Haskell] устранение утечек памяти, FastCGI

minoru-kun · Сообщение **minoru-kun** » 30.05.2010 17:37

Имею следующий кусок кода:

Код:


import Network.FastCGI
import Random
import Data.Maybe
import Control.Monad
import Control.Exception as E

handleRequest :: StdGen -> CGI (Int,StdGen)
handleRequest gen = do low <- getInput("low")
		       high <- getInput("high")
		       let rnd = randomR (read (fromJust low) :: Int,read (fromJust high) :: Int) gen
		       liftIO $ (runOneFastCGI . output) (show (fst rnd))
		       return rnd

main = do gen <- newStdGen
	  let cgi_handler x = x >>= \(_,gen) -> handleRequest gen
	      cgi_process x = x >>= \(result,_) -> output (show result)
	      error_handler x = E.catch x (\err -> (runOneFastCGI . output) ("Error: " ++ show (err :: ErrorCall)))
	  runFastCGI $ forever $ sequence_ $ iterate cgi_handler (return (1, gen))

Все бы хорошо, но течет оперативка (приблизительно 60мб за 100 000 обращений).
Я изменил код следующим образом:

Код:


import Network.FastCGI
import Random
import Data.Maybe
import Control.Monad
import Control.Exception as E

handleRequest :: StdGen -> CGI (Int,StdGen)
handleRequest gen = do low <- getInput("low")
		       high <- getInput("high")
		       let rnd = randomR (read (fromJust low) :: Int,read (fromJust high) :: Int) gen
		       liftIO $ (runOneFastCGI . output) (show (fst rnd))
		       return rnd
cgi_handler x = x >>= \(_,gen) -> handleRequest gen
cgi_process x = x >>= \(result,_) -> output (show result)
error_handler x = E.catch x (\err -> (runOneFastCGI . output) ("Error: " ++ show (err :: ErrorCall)))

main = do gen <- newStdGen
--	  runFastCGI $ forever $ sequence_ $ iterate cgi_handler (return (1, gen))
	  runFastCGI $ cgi_process $ last $ take 50000 $ iterate cgi_handler (return (1, gen))

и скормил профайлеру:

Код: Выделить всё

minoru@debian:~/src$ ghc --make -prof -auto-all simplefcgi3.hs
[1 of 1] Compiling Main             ( simplefcgi3.hs, simplefcgi3.o )
Linking simplefcgi3 ...

Код: Выделить всё

#!/bin/bash
./simplefcgi3 +RTS -p

В результате получил вот такой дамп:

Код:


	Fri May 14 11:22 2010 Time and Allocation Profiling Report  (Final)

	   simplefcgi3 +RTS -p -RTS

	total time  =        0.04 secs   (2 ticks @ 20 ms)
	total alloc =   5,894,808 bytes  (excludes profiling overheads)

COST CENTRE                    MODULE               %time %alloc

main                           Main                  50.0   61.4
cgi_handler                    Main                  50.0   37.3


                                                                                               individual    inherited
COST CENTRE              MODULE                                               no.    entries  %time %alloc   %time %alloc

MAIN                     MAIN                                                   1           0   0.0    0.0   100.0  100.0
 CAF                     Main                                                 440          10   0.0    0.0   100.0   98.8
  cgi_process            Main                                                 448           1   0.0    0.0     0.0    0.0
  main                   Main                                                 446           1  50.0   61.1   100.0   98.8
   cgi_handler           Main                                                 449       49999  50.0   37.3    50.0   37.7
    handleRequest        Main                                                 450           1   0.0    0.4     0.0    0.4
 CAF                     Data.Typeable                                        438           1   0.0    0.0     0.0    0.0
 CAF                     GHC.IO.Exception                                     432           9   0.0    0.1     0.0    0.1
 CAF                     GHC.Read                                             417           1   0.0    0.0     0.0    0.0
 CAF                     GHC.Exception                                        413           3   0.0    0.0     0.0    0.0
 CAF                     Data.Maybe                                           412           2   0.0    0.0     0.0    0.0
 CAF                     Text.Read.Lex                                        405           8   0.0    0.0     0.0    0.0
 CAF                     Data.HashTable                                       379           2   0.0    0.0     0.0    0.0
 CAF                     GHC.IO.Handle.FD                                     377           2   0.0    0.4     0.0    0.4
 CAF                     System.Posix.Internals                               376           1   0.0    0.0     0.0    0.0
 CAF                     GHC.Conc                                             360           4   0.0    0.0     0.0    0.0
 CAF                     GHC.IO.Handle.Internals                              351           1   0.0    0.0     0.0    0.0
 CAF                     GHC.IO.Encoding.Iconv                                345           3   0.0    0.0     0.0    0.0
 CAF                     System.Random                                        338           1   0.0    0.1     0.0    0.1
 CAF                     Data.Fixed                                           332           2   0.0    0.0     0.0    0.0
 CAF                     Data.Time.Clock.POSIX                                330           2   0.0    0.0     0.0    0.0
 CAF                     Data.Time.Clock.CTimeval                             329           1   0.0    0.0     0.0    0.0
 CAF                     Network.FastCGI                                      310           5   0.0    0.0     0.0    0.3
  main                   Main                                                 447           0   0.0    0.3     0.0    0.3
 CAF                     Network.CGI.Protocol                                 309           7   0.0    0.1     0.0    0.1
 CAF                     Control.Monad.Trans                                  287           1   0.0    0.0     0.0    0.0

Как видно, течет cgi_handler и main (очевидно, iterate, который его дергает. Как можно избавиться от течи? Использовать какой-нибудь MVar не хотелось бы.