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COM+ Call Timers: the unofficial way

Not satisfied with the official way, I went looking for a simpler way. The Component Services Console displays the data so the information must be there somewhere. It is a waste of time and resources me to collect the data and calculate the call times when the information I want is already available.

As it turns out the unofficial way is a lot simpler to implement than the official way.

Step 1: include the comsvc.dll library
// ComSvcs library for internal com+ method call tracking
#import "c:\windows\system32\comsvcs.dll" exclude("IAppDomainHelper")

Step 2: get the statistics

• Get an instance of the internal com+ tracker:  COMSVCSLib::IGetAppDataPtr ptrAppData(_T("{ecabafb9-7f19-11d2-978e-0000f8757e2a}"));
  
• Get a list of applications and lop through them:  ptrAppData->GetApps(&nAppData, &appData);
  
  
  
  • Get the application data you are interested in: calls per second, total calls, etc
    
  • Get a list of classes in the application and loop on them, extracting the information you want: ptrAppData->GetAppData(oneApp.m_idApp, &nClsIDs, &aClsidData);

Example
This simple routine builds a XML string the brutal way with the com+ performance information (most error handling code removed for clarity)

/*

 Get the statistics from the hidden COM+ interface

 */

void CTracker::getStatistics(BSTR *output)

{

      const unsigned long MAX_APP_DATA = 500;

      const unsigned long PUSH_RATE = 1000;

 

      unsigned long nAppData = MAX_APP_DATA;

      LPSTR lpString;

      LPWSTR lpwString;

 

      COMSVCSLib::appData *aAppData;

 

      CString csStatistics = "";

 

      // Get an instance of the internal com+ tracker objet

      COMSVCSLib::IGetAppDataPtr ptrAppData(_T("{ecabafb9-7f19-11d2-978e-0000f8757e2a}"));

      csStatistics.Append("\r\n");

 

      // Step through the list of running application

      ptrAppData->GetApps(&nAppData, &aAppData);

      for (unsigned long idxApp=0; idxApp < nAppData; idxApp++)

      {

            unsigned long nClsIDs;

            COMSVCSLib::CLSIDDATA *aClsidData;

            COMSVCSLib::appData oneApp = aAppData[idxApp];

 

            csStatistics.Append(_T("\r\n"));

            UnicodeToAnsi(oneApp.m_szAppGuid, &lpString);

            csStatistics.AppendFormat(_T("%s\r\n"), lpString);

            CoTaskMemFree(lpString);

 

            // Application information

            csStatistics.AppendFormat(_T("%ld\r\n"), oneApp.m_idApp);

            csStatistics.AppendFormat(_T("%ld\r\n"), oneApp.m_dwAppProcessId);

           

            COMSVCSLib::APPSTATISTICS appStatistics = oneApp.m_AppStatistics;

            csStatistics.AppendFormat(_T("\r\n"));

            csStatistics.AppendFormat(_T("\t%ld\r\n"), appStatistics.m_cCallsPerSecond);

            csStatistics.AppendFormat(_T("\t%ld\r\n"), appStatistics.m_cTotalCalls);

            csStatistics.AppendFormat(_T("\t%ld\r\n"), appStatistics.m_cTotalClasses);

            csStatistics.AppendFormat(_T("\t%ld\r\n"), appStatistics.m_cTotalInstances);

            csStatistics.AppendFormat(_T("\r\n"));

 

            // Get class information for this application

            ptrAppData->GetAppData(oneApp.m_idApp, &nClsIDs, &aClsidData);

            csStatistics.AppendFormat(_T("\r\n"));

            for (unsigned long idxClass = 0 ; idxClass < nClsIDs; idxClass++)

            {

                  COMSVCSLib::CLSIDDATA oneClass = aClsidData[idxClass];

                  csStatistics.AppendFormat(_T("\r\n"));

                 

                  // Get the progID for the guid.

                  // This FAILS during recyling on Win2k3

                  if (!FAILED((ProgIDFromCLSID(oneClass.m_clsid,&lpwString))))

                  {                 

                        UnicodeToAnsi(lpwString, &lpString);

                        csStatistics.AppendFormat(_T("\t%s\r\n"), lpString);

                        CoTaskMemFree(lpString);

                  }

 

                  // Performance information

                  csStatistics.AppendFormat(_T("\t%ld\r\n"), oneClass.m_cBound);

                  csStatistics.AppendFormat(_T("\t%ld\r\n"), oneClass.m_cInCall);

                  csStatistics.AppendFormat(_T("\t%ld\r\n"), oneClass.m_cPooled);

                  csStatistics.AppendFormat(_T("\t%ld\r\n"), oneClass.m_cReferences);

                  csStatistics.AppendFormat(_T("\t%ld\r\n"), oneClass.m_dwRespTime);

                  csStatistics.AppendFormat(_T("\t%ld\r\n"), oneClass.m_cInCall);

                  csStatistics.AppendFormat(_T("\t%ld\r\n"), oneClass.m_cInCall);

                 

                  csStatistics.AppendFormat(_T("\r\n"));

            }

            CoTaskMemFree(aClsidData);

            csStatistics.AppendFormat(_T("\r\n"));

            csStatistics.AppendFormat(_T("\r\n"));

      }

      csStatistics.Append("\r\n");

      CoTaskMemFree(aAppData);

 

      *output = csStatistics.AllocSysString(); 

}

 
That's it!
Less than a 100 lines of code to build a XML document with the call times for the running COM+ applications on the system.

This approach as several benefits over the official way:

• It is a lot simpler to implement and maintain (100 lines of C++ vs 1.500)
  
• I have found no memory leaks after 9 months in production
  
• Less resource usage. COM+ already maintains the counters, I just get them when I need them.

Keep in mind that this is an undocumented API so it may change one day in the future (Longhorn?).