Question

查看使用*.prof生成的+RTS -p文件并启用了分析编译，我看到很多名为\的子例程：

COST CENTRE           MODULE                         %time %alloc

main.\.\.\            Main                            74.1   85.8
unstreamChunks/inner  Data.Text.Internal.Lazy.Fusion  11.9    8.6 
inverseLetters.\      Main                             4.5    1.7 
main.\.\.\.(...)      Main                             2.9    1.0 
main.\.\.\.(...)      Main                             2.8    1.0 
unstreamChunks/resize Data.Text.Internal.Lazy.Fusion   1.2    0.8 
unstreamChunks/outer  Data.Text.Internal.Lazy.Fusion   1.1    0.5

对我来说看起来很神秘。这些代表什么？

Answer 1

让

public message getDetailedMessage(int message_id)
{
    message msg = new message();

    if(context.messages.Any(mesg => (mesg.C_From == CurrentUser.Id &&  mesg.id == message_id) || (mesg.Receivers.Any(receiver => receiver.ReceiverId == CurrentUser.Id && receiver.MessageId == message_id))))
    {
        msg = context.messages.Where(mesg => mesg.id == message_id).FirstOrDefault();
        msg.Status = "R";
        context.SaveChanges();
    }
    else
    {
        msg.MDTO.HasError = true;
        msg.MDTO.Error = "You do not have the permission to read this inbox";
    }

    return msg;
}

并使用

运行

import Control.Monad

main = do
    forM_ [1..1000] $ \i ->
        if mod i 2 == 0 then putStrLn "Foo"
                        else print i

然后，在rules to set cost centres

之后

ghc -rtsopts -prof -fprof-auto z.hs && ./z +RTS -p && cat z.prof

反斜杠显示堆栈级别you can set names for each one

COST CENTRE MODULE           %time %alloc
main.\      Main              80.0   84.4
main        Main              20.0   13.2
CAF         GHC.IO.Handle.FD   0.0    2.1

现在

forM_ [1..1000] $ \i ->
    {-# SCC "myBranch" #-}
    if mod i 2 == 0 then putStrLn "Foo"
                    else print i

（添加@trVoldemort评论）

此外，COST CENTRE MODULE %time %alloc myBranch Main 90.0 84.4 main Main 10.0 13.2 CAF GHC.IO.Handle.FD 0.0 2.1似乎用于涉及计算的(...)作业

let

带有配置文件输出

data T = T Int (IO ()) (IO ())
main =
   forM_ [T (mod i 2) (putStrLn "Foo") (print i) | i <- [1..1000]] $ \q ->
        let T a b c = q -- Will be `(...)`
        in  if a == 0 then b else c

使用SCC编译指示

main.\        Main
 main.\.b     Main
 main.\.c     Main
 main.\.(...) Main
 main.\.a     Main

和输出

forM_ [T (mod i 2) (putStrLn "Foo") (print i) | i <- [1..1000]] $ \q ->
     let T a b c = {-# SCC "myBind" #-} q
     in  if a == 0 then b else c

为什么* .prof文件中有这么多反斜杠（\）？

1 个答案: