Re: Loops per second of thread suddenly drops

Thanks for your reaction!
Well that's the strange thing about this all: The thread I start isn't
really doing anything with the GUI at all. It's just nicely doing it's
calculations on its own, minding its own business, unless I'm horribly
missing something here.

All that I do have is a timer set to 1 sec, and on the OnTimer() event I
read the counter that is being incremented by the worker thread every loop
and put it back to 0 again.
I then put the value I've read onto a static text object on the GUI. But
this is all happening only once a second.

Also, I forgot to mention, after the lps has dropped, it goes back up to
30-35 again as well after a while. I've used Process Explorer, and I do think
I see a slight increase in CPU usage when the lps drop, but mainly stuff like
svchost and opera using some CPU time, not much more.

Here is some code:

DWORD WINAPI Thread(LPVOID pParam) {
  CMyDlg * pMyDlg;
  pMyDlg = (CMyDlg *) pParam;
  return pMyDlg->MainLoopFunc();
}

BOOL CMyDlg::OnInitDialog() {
  HANDLE hThread = CreateThread(NULL, 0,
           Thread, this, 0, NULL);
  SetTimer(1, 1000, 0);
}

void CAmbloneDlg::OnTimer(UINT_PTR nIDEvent) {
  CString Text;
  Text.Format("Loops per second: %d lps", loopc);
  StaticLoops.SetWindowTextA(Text);
  loopc = 0;

  CDialog::OnTimer(nIDEvent);
}

And this is the main function:

UINT CAmbloneDlg::MainLoopFunc() {

//--------------------------------------------
// Get some information about the screen etc.
// -------------------------------------------

  ZeroMemory(&dd, sizeof(dd));
  dd.cb = sizeof(dd);

  do {
    if (EnumDisplayDevices(NULL, settings.GetDisplayDeviceNum(), &dd, NULL)) {
      // We found the monitor, now get the screen DC
      hScrDC = CreateDC(NULL,dd.DeviceName,NULL,NULL);

      // Get the screen resolution
      xScrn = GetDeviceCaps(hScrDC, HORZRES);
      yScrn = GetDeviceCaps(hScrDC, VERTRES);

      // Create a bitmap compatible with the screen DC
      hBitmap = CreateCompatibleBitmap(hScrDC, xScrn, yScrn);

      // Create a memory DC compatible to screen DC
      hMemDC = CreateCompatibleDC(hScrDC);

      // Create a rectangle
      GetClientRect(&rect);

      pDC = GetDC(); // Get the DC

      do {
        // ----------------------
        // This is the main loop
        // ----------------------

        // Calculate the average screen pixel colour
        GetAverageRGB();

        // Now output the colour
        OutputColour();

        if (counting) loopc++;

      } while (KeepRunning);
    }
    DeleteDC(hScrDC);
    DeleteDC(hMemDC);

  } while (restart);
  return 0;
}