Question

I have a client/server application written in delphiXe2 using Indy TIdTCPServer and TIdTCPClient that communicates with each other on the same computer using TCP address 127.0.0.1

When i use about 1 megs per second(8 Megabit) of data everything works fine.

However when set my data at higher speed like 20megs/sec (160 Megabit), it slow down and start to behave weirdly.

Is that an usual behavior for that speed?
Also i can’t seem to find any benchmark or information of what is the maximum data transfer speed between 2 local application.

Regards

Answer 1

Perform a bandwidth test. This is what I use (I have attached the relevant server and client code). FWIW, I get around 500Mbps maximum, although there is no way I could process data that fast.

procedure TForm1.IdTCPServer1Execute(AContext: TIdContext);
var
  lData: TByteDynArray;
  lCaption: string;
  lMbps: Real;
  lLen: Integer;
begin
  AContext.Connection.IoHandler.CheckForDataOnSource;
  SetLength(lData, 0);
  AContext.Connection.IoHandler.InputBuffer.ExtractToBytes(TIdBytes(lData),
                                     AContext.Connection.IoHandler.InputBuffer.Size);
  lLen := Length(lData);
  if lLen > 0 then begin
    if FStartTime = 0 then begin
      Memo1.Lines.Add(FormatDateTime('dd/mm/yyyy hh:nn:ss.zzz', CsiNow) +': Started test');
      FStartTime := CsiNow;
    end;
    Inc(FBytesReceived, lLen);
    lCaption := 'MBits Received: ' + CsiPadFloat(FBytesReceived * 1.0 / 125000, 3, 1);
    if lCaption <> FLastCaption  then begin
      Label1.Caption := lCaption;
      FLastCaption := lCaption;
    end;
    if FBytesReceived >= 12500000 then begin
      FStopTime := CsiNow;
      lMbps := 100000 / MilliSecondsBetween(FStopTime, FStartTime);
      Memo1.Lines.Add(FormatDateTime('dd/mm/yyyy hh:nn:ss.zzz', CsiNow) +
                      ': Finished test (' + CsiPadFloat(lMbps, 3, 1) + ' Mbps)');
      FBytesReceived := 0;
      FStartTime := 0;
    end
  end;

  CsiSleep(0);
end;

procedure TForm1.Button1Click(Sender: TObject);
var
  lData: TByteDynArray;
  lIndex: Integer;
begin
  IdTCPClient1.Host := Edit1.Text;
  IdTCPClient1.Connect;
  try
    SetLength(lData, 125000);
    for lIndex := 1 to 125000 do
      lData[lIndex - 1] := Ord('a');
    for lIndex := 1 to 100 do
      IdTCPClient1.IoHandler.Write(TIdBytes(lData));
  finally
    IdTCPClient1.Disconnect;
  end;
end;