TCP connection slows down after a while

[JohnNash]

I am connectin a autoit code on my machine with an autoit code on my virtual machine.  It works mainly by instructing eachother through TCPSend and receive. All well, all good. Runs like a train. We however notice on every occasion that a certain action that is triggered by such a message slows down in reaction time after an hour or so. 

We personally suspect is has something to do with the fact that we send a lot of messages both ways and some buffer might get full or something like that? We googled for TCP flush/buffer + autoit but found nothing conclusive ... any idea? Should we clear something?

[AutoBert]

Bad implementation of TCP in one or both of your scripts.

[JohnNash]

 Yes I also suspect that. 

Minimal example (hope I didnt delete too much)

 

 

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MINIMAL CLIENT.au3
;communication======================================================================
Global $MainSocket
Local $MaxLength = 512              ;Maximum Length Of Text
Local $Port = 8080                  ;Port Number
Local $Server = "xxx"


TCPStartup()                        ; Start the TCP service.
$MainSocket = TCPConnect($Server, $Port)
If $MainSocket = -1 Then Exit MsgBox(16, "Error", "Unable to connect.")



;MAINLOOP?**********************************************************************************************************************************************************************
While 1
Local $fDiff = TimerDiff($hTimer) ; What is difference between time now and
   $Data=0
   $Data = TCPRecv($MainSocket, $MaxLength)
 ; MsgBox(16,"MessageDebug",$Data)
   If $Data = "ByeBye" Then
   MsgBox($MB_SYSTEMMODAL, "Closing Down Client and Server", "Shutting Down", 1)
   Terminate()
   EndIf



If CountInstances() < $sAnswer And $fDiff > 15000 Then
      OpenNewInstance()

         sleep(500);safety loop

      EndIf

      WEnd
;*******************************************************************************************************************************************************************************






Func OpenANewInstance()
  $hTimer = TimerInit() ; Begin the timer and store the handle in a variable.
AcutalOpeningOfinstance(); here we open something on Client
;HERE we check whether it is opened (omitted)

TCPSend($MainSocket, "Server do your Thing")

While 1
    $Data = TCPRecv($MainSocket, $MaxLength)
    sleep(100)
    If $Data = "Client please Continue" Then
    
    ExitLoop
    EndIf
WEnd


EndFunc

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MINIMAL SERVER. au3



Global $MainSocket = -1
Global $ConnectedSocket = -1
Local $MaxConnection = 1; Maximum Amount Of Concurrent Connections
Local $MaxLength = 512; Maximum Length Of String
Local $Port = 8080; Port Number
Global $Server = InputBox("Question", "IP", "xxxx", "", _
             - 1, -1, 0, 0)

TCPStartup()
$MainSocket = TCPListen($Server, $Port)
If $MainSocket = -1 Then Exit MsgBox(16, "Error", "Unable to intialize socket.")

Global $switch = 0
While 1


 If $ConnectedSocket = -1 Then
$ConnectedSocket = TCPAccept($MainSocket)
endif
   
$Data = TCPRecv($ConnectedSocket, $MaxLength)
            If $Data = "ByeBye" Then
            Terminate()
            ;MsgBox(16, "Session Ended", "Connection Terminated.")
            ;Exit


            Elseif $Data = "Server do your Thing" Then
        
            ;Here We do Stuff and then
                        TCPSend($ConnectedSocket, "Client please Continue") 

            EndIf

 WEnd

 

[JohnNash]

I deleted some stuff, for example $sAnswer is a number of instances of a certain program we want to have opened. Note that the sending and receiving works well initially and the code runs as expected. But like i said, it will slow down after an hour, and becomes slower and slower.

 

[AutoBert]

35 minutes ago, JohnNash said:

$sAnswer is a number of instances of a certain program we want to have opened

each instance needs resources and so i am not wondering when pc slows down. 

[JohnNash]

Just now, AutoBert said:

each instance needs resources and so i am not wondering when pc slows down. 

Hmm but they are also closed after it served its purpose. So never are there more instances open than 3 for example. Plus, in the beginning everything runs smoothly. I really noticed it is the sending  + receiving of the command that gets delayed. But no clue why

[Dent]

Have you taken a look at Task Manager? Make sure you click 'Show processes from all users' and have a look and see if there is any high CPU/Memory loads from particular processes. You can then trace these back to particular services for instance is svchost.exe is using up a lot of resource, you can then break this down.

 

It does sound to me like some handle or other isn't being closed and freed up properly after use.

[JohnNash]

Thanks, yes in the mean time I checked, but saw nothing special. Does anyone see something peculiar about my code?

I googled some more and found some articles about bufferbloat, could that be relevant?