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I have developed a screenshot application in VC++ 2005. It will take screenshots and save it in the server MYSQL database. The process is that, initially the file will be saving in C: drive, then after taking the blob data, the file will be removed. But it has been installed almost all system in my office. The problem is that, it takes more than 65% CPU usage. How to avoid this. Please help me. AFX_ODBC_CALL(::SQLExecute(m hstmt) takes too long......
void gdiscreen()
{
	using namespace Gdiplus;
	GdiplusStartupInput gdiplusStartupInput;
	ULONG_PTR gdiplusToken;
	GdiplusStartup(&gdiplusToken, &gdiplusStartupInput, NULL);
	int c=0;
	HDC scrdc, memdc;
	HBITMAP membit;
	HBITMAP hOldBitmap;
	CString lpfilename;
	char buffer[1000];	   
	
	for(;;)
	{		
		scrdc = ::GetDC(0);
		int Height = GetSystemMetrics(SM_CYSCREEN);
		int Width = GetSystemMetrics(SM_CXSCREEN);
		memdc = CreateCompatibleDC(scrdc);
		membit = CreateCompatibleBitmap(scrdc, Width, Height);
		hOldBitmap=(HBITMAP) SelectObject(memdc, membit);
		BitBlt(memdc, 0, 0, Width, Height, scrdc, 0, 0, SRCCOPY);
		//Gdiplus::Bitmap bitmap(membit, NULL);
		Gdiplus::Bitmap* bitmap =  ::new Bitmap(membit, NULL );

		CLSID clsid;
		GetEncoderClsid(L"image/jpeg", &clsid);
		sprintf_s(buffer,"C:\\Program Files\\image%u.jpeg",c);		
		lpfilename=buffer;				
		bitmap->Save(lpfilename, &clsid); 
		IStream* tmpbuf = NULL;
		CreateStreamOnHGlobal(NULL, true, &tmpbuf);
		bitmap->Save(tmpbuf, &clsid);
		HGLOBAL hg = NULL;
		HRESULT  hr = GetHGlobalFromStream(tmpbuf, &hg);
		SIZE_T uSize = GlobalSize(hg);
		//GlobalUnlock(hg);
		

		int len=(int)uSize;  
		CFile file;
		BYTE buf[150];
		CStringA charstr(lpfilename);
		CString strblob;
	   const char *szSingle;
       szSingle=((const char *) charstr);	

		CString strDateTime;
	   SYSTEMTIME datetimenew;
			::GetLocalTime(&datetimenew);
			strDateTime.Format(_T("%02i-%02i-%02i %d:%d:%d"),
								datetimenew.wYear,
								datetimenew.wMonth,     
								datetimenew.wDay,       
								datetimenew.wHour,
								datetimenew.wMinute,
								datetimenew.wSecond);
		
		CdbImages       dbImages(&theApp.m_DB);

		dbImages.Open();
        dbImages.AddNew();

        CFile		fileImage;
        CFileStatus	fileStatus;

        fileImage.Open(lpfilename, CFile::modeRead);
        fileImage.GetStatus(fileStatus);

		dbImages.m_dateTime = strDateTime;
        //dbImages.m_BLOBName = fileImage.GetFileTitle();		
		dbImages.m_BLOBName = SqlStr3;
		
        dbImages.m_BLOBImage.m_dwDataLength = fileStatus.m_size;

        HGLOBAL hGlobal		= GlobalAlloc(GPTR,fileStatus.m_size);
        dbImages.m_BLOBImage.m_hData = GlobalLock(hGlobal);
		
        fileImage.Read(dbImages.m_BLOBImage.m_hData,fileStatus.m_size);
		dbImages.SetFieldDirty(&dbImages.m_BLOBImage);
        dbImages.SetFieldNull(&dbImages.m_BLOBImage,FALSE);
		dbImages.m_log_user = loguser;
        dbImages.Update();
		fileImage.Close();		
		 dbImages.Close();
		 GlobalUnlock(hGlobal);
		
		::delete bitmap;
		bitmap = NULL;
		DeleteObject(memdc);
		DeleteObject(membit);
		::ReleaseDC(0,scrdc);
		CFile::Remove(lpfilename);    		
			
		
		 //Sleep(10000);			 
		 int iSecret, iRandom;  
		 iSecret = rand() % 20 + 1;
		iRandom=iSecret*60000;
		Sleep(iRandom);
	    c++;	    
		}		
		
		GdiplusShutdown(gdiplusToken); 
}

int GetEncoderClsid(const WCHAR* format, CLSID* pClsid)
{
	using namespace Gdiplus;
	UINT  num = 0;          // number of image encoders
	UINT  size = 0;         // size of the image encoder array in bytes

	ImageCodecInfo* pImageCodecInfo = NULL;
	GetImageEncodersSize(&num, &size);
	if(size == 0)
		return -1;  // Failure

	pImageCodecInfo = (ImageCodecInfo*)(malloc(size));
	if(pImageCodecInfo == NULL)
		return -1;  // Failure

	GetImageEncoders(num, size, pImageCodecInfo);

	for(UINT j = 0; j < num; ++j)
	{
		if( wcscmp(pImageCodecInfo[j].MimeType, format) == 0 )
		{
			*pClsid = pImageCodecInfo[j].Clsid;
			free(pImageCodecInfo);
			return j;  // Success
		}    
	}

	free(pImageCodecInfo);
	return 0;
}
Posted
Updated 26-Jul-11 20:59pm
v5
Comments
[no name] 14-Jul-11 8:40am    
Network traffic and CPU usage are two different things, please do not confuse. You may want to rephase your question and change the title too.
CPallini 14-Jul-11 9:18am    
Are you spying your mates?
Jamesmeng 14-Jul-11 20:05pm    
I think so.
Joan M 14-Jul-11 9:47am    
Probably you would finish before if you would use a keylogger software :( anyway... could you tell us which part of the code is taking so much CPU and show us the program?
ThatsAlok 27-Jul-11 3:30am    
just a small comment, save your codec, instead of calling function again and again

You probably have a loop running as fast as it can, you can avoid this by adding some sort of pacing. For example, if you're taking screen shots and sending them out to a database as fast as possible, its possible that your loop is taking up a large amount of CPU time. For efficiency, you'd want to have a settable time interval that would pace this time of operation. Of course, without any code, its just a guess as to what's using so much CPU time.
 
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Sergey Alexandrovich Kryukov 14-Jul-11 22:58pm    
My 5. Some notes. It can be anything. In particular, high CPU load is a sign of polling; anything polling by timer is evil, no matter what the time interval is. Right approach is in version control; a service part gets subscription from clients and notifies only if changes comes. Client should be listening (and thus wasting no CPU time) when nothing happens. Client-server is a dead schema, not suitable for data acquisition at all. Dominance if client-server is a sorrow fact.
--SA
Sergey Chepurin 15-Jul-11 5:06am    
I hope you are kidding. Every technological process is periodical by definition (i.e. organized somehow). You need data not when it is changed but only when you can handle new portion of it, i.e. after predefined time period (and even if nothing changes).
Albert Holguin 15-Jul-11 8:37am    
Have you ever used VNC? Guess not, you set a sample rate. Have you ever done DSP? Guess not, because you've never heard of a sample rate.
Gokulnath007 18-Jul-11 6:02am    
If I execute this in my local system database, it is working fine. But while using the server database, it takes much CPU usage and the system hangs because of this.
Albert Holguin 18-Jul-11 10:43am    
In your local system there's probably absolutely no network lag in moving data to/from the database... over a server, you introduce a new variable, accessing a remote database. Reduce the amount of interactions with the database as much as possible.
Stop writing programs, especially those spying on your colleagues. It will free up a good deal of CPU.

—SA
 
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Albert Holguin 15-Jul-11 8:38am    
lol, good point!
Sergey Alexandrovich Kryukov 19-Jul-11 0:27am    
Thank you, Albert. But some comrades do not understand the point :-)
--SA
From your short explanation, it is really hard to figure out what you are doing. How often do you capture those screenshots ?

Have you considered compressing the image before archival, using the JPEG format for instance ?
 
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Gokulnath007 15-Jul-11 1:06am    
I have updated the question with the code I am using to take the screenshots and saving it to the database.
YDaoust 15-Jul-11 2:33am    
From what I understand of the code, screen capture takes place less than every minute. Complete capture and archival of the screenshots should take a fraction of a second. So what is the problem ?

If processing takes longer, you must profile your code to know what is slowing it abnormally.
Gokulnath007 15-Jul-11 5:40am    
I have checked it in all possible ways, the process and the CPU usage gets on increasing and after sometime it becomes very low. Gradual increase and decrease of CPU Usage which decreases the machine performance.
YDaoust 15-Jul-11 5:55am    
"I have checked it in all possible ways": what do you mean ?

I am confused by your explanation with increases and decreases. How long does a capture last ?

What about memory usage ?
Gokulnath007 15-Jul-11 6:14am    
It takes the screenshots randomly, because i have used rand() function to get a number from 1 to 20 and then convert it into milliseconds and used sleep to wait the thread. Initially it takes the screenshots and save the file in path, after taking the binary data and saving it to the blob field of the database used CFile:: Remove() to delete the file saved in hard disk.

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