50% datagram drop with Indy

Thread View: borland.public.cppbuilder.internet.socket

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2 total messages Started by syncopator Tue, 29 Jan 2008 21:29

#587

Author: syncopator
Date: Tue, 29 Jan 2008 21:29

39 lines
2383 bytes

I'm reading UDP datagrams from my camera over a closed network.  The camera 
is connected directly to my network card with a crossover cable and is on a 
static IP.  It sends 1000 datagrams per second, each one is 1.3 KB.  So it's 
roughly 13% of the 100T.
I'm using the UDP server from Indy 8, and receiving 50% of the packets.  The 
data is of the correct size and is valid.  I'm running the server in a high 
priority thread and have stripped away all the processing.
I originally implemented the code with FastNet, and I was getting 2% drops.
Any help would be greatly appreciated.

DWORD WINAPI ThreadFunc(LPVOID Param) {
   HANDLE MainWnd (Param);
   char Buffer[8192];
   int i,j, port, Len;
   while (true){
      Len=Form1->Server->ReceiveBuffer(Buffer,8192) ;
      dcnt++;
      pcnt+=Len;


__fastcall TForm1::TForm1(TComponent* Owner)
        : TForm(Owner)
{
   DWORD Id;
   Thread= CreateThread(0,0,ThreadFunc,
      Form1->Handle,CREATE_SUSPENDED,&Id);
   if(!Thread){
      ShowMessage("Error Creating Thread");
   }

}
//---------------------------------------------------------------------------

void __fastcall TForm1::Button1Click(TObject *Sender)
{
    SetPriorityClass( Thread,REALTIME_PRIORITY_CLASS );
    ResumeThread(Thread);
    Timer1->Enabled = true;
}

Re: 50% datagram drop with Indy

#402

Author: Remy Lebeau (TeamB)
Date: Wed, 30 Jan 2008 06:45

24 lines
1849 bytes

"syncopator" <bobback@inbox.com> wrote in message
news:479f9abe$1@newsgroups.borland.com...

> I'm using the UDP server from Indy 8, and receiving 50% of the packets.

That is because you are not taking into account that TIdUDPServer runs its
own threads internally for receiving packets.  So you are reading from the
same socket in multiple threads simultaneously.  Some data is going to be
received in your thread, and some data in TIdUDPServer's threads.

> I'm running the server in a high priority thread

Whatever you do to the thread that owns the TIdUDPServer instance will not
apply to the threads that TIdUDPServer creates internally.

>       Len=Form1->Server->ReceiveBuffer(Buffer,8192) ;

If you are going to do that in your own thread, then TIdUDPServer is the
wrong component to use.  Otherwise, you should let TIdUDPServer handle the
threading for you, and you can simply adjust its priority as needed.


Gambit

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