haskell网络性能差

绳子慢了。真的,真的,真的很慢。这是一个单独链接的cons单元格列表,每个单元格包含一个unicode字符。将一个字符写入套接字需要将每个字符转换为字节,将这些字节复制到一个数组中,并将该数组传递给系统调用。你想做什么?:)

您想独占使用ByteString。ByteString IO函数实际上尽可能使用零拷贝IO。尤其是看看 network-bytestring 关于黑客的包裹。它包含所有网络库的版本,这些网络库经过优化,可以有效地使用ByteString。

下面是两个示例程序:客户机和服务器。使用GHC 7.0.1和network-2.3,我在我全新的双核笔记本电脑上通过环回获得了超过7500 Mbps的速度(约占总CPU使用率的90%)。我不知道UDP引入了多少开销,但这是一个相当大的数字。

--------------------
-- Client program --
--------------------
module Main where

import qualified Data.ByteString as C
import Network.Socket hiding (recv)
import Network.Socket.ByteString (recv)

import System.IO
import Control.Monad

main :: IO ()
main = withSocketsDo $
    do devNull <- openFile "/dev/null" WriteMode
       addrinfos <- getAddrInfo Nothing (Just "localhost") (Just "3000")
       let serveraddr = head addrinfos
       sock <- socket (addrFamily serveraddr) Stream defaultProtocol
       connect sock (addrAddress serveraddr)
       forever $ do
         msg <- recv sock (256 * 1024) -- tuning recv size is important!
         C.hPutStr devNull msg
       sClose sock


--------------------
-- Server program --
--------------------
module Main where

-- import Control.Monad (unless)
import Network.Socket hiding (recv)
import qualified Data.ByteString.Lazy as S
import Network.Socket.ByteString.Lazy (
                                       --recv, 
                                       sendAll)

main :: IO ()
main = withSocketsDo $
       do addrinfos <- getAddrInfo
                        (Just (defaultHints {addrFlags = [AI_PASSIVE]}))
                        Nothing (Just "3000")
          let serveraddr = head addrinfos
          sock <- socket (addrFamily serveraddr) Stream defaultProtocol
          bindSocket sock (addrAddress serveraddr)
          listen sock 1
          (conn, _) <- accept sock
          talk conn
          sClose conn
          sClose sock

     where
       talk :: Socket -> IO ()
       talk conn = sendAll conn $ S.repeat 7

卡尔对你的前两个问题是对的。关于你的上一个,考虑使用 the strict concurrency package .