How to Allow Poolmon.exe to Run by Setting GlobalFlag Value

• Microsoft Windows NT Workstation versions 3.5, 3.51, and 4.0
• Microsoft Windows NT Server versions 3.5, 3.51, and 4.0

IMPORTANT: This article contains information about editing the registry. Before you edit the registry, make sure you understand how to restore it if a problem occurs. For information about how to do this, view the "Restoring the Registry" Help topic in Regedit.exe or the "Restoring a Registry Key" Help topic in Regedt32.exe.

SYMPTOMS

The utility Poolmon.exe located on the Windows NT CD-ROM can be used to track memory usage in both paged and nonpaged pools of memory. When POOLMON is run from the command prompt of Windows NT, the following error is displayed:

   Query pooltags Failed c0000002

CAUSE

Poolmon.exe uses a global pooltag in the registry located at a value called GlobalFlag. The default value for GlobalFlag is 0, so Windows NT does not expend extra overhead in gathering pooltag information.

RESOLUTION

WARNING: Using Registry Editor incorrectly can cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk.

For information about how to edit the registry, view the "Changing Keys And Values" Help topic in Registry Editor (Regedit.exe) or the "Add and Delete Information in the Registry" and "Edit Registry Data" Help topics in Regedt32.exe. Not that you should back up the registry before you edit it.

To allow Windows NT to gather pooltag information, the GlobalFlag value must be changed using Registry Editor (Regedt32.exe). Before making changes, write down the current value of GlobalFlag so that it can be reset once running Poolmon.exe is no longer necessary.

The following hex values for GlobalFlag will set up memory tagging in Windows NT for the following versions:

Windows NT 3.5: 0x01000000 Windows NT 3.51: 0x00000400 Windows NT 4.0: 0x00000400

If you are running Windows NT version 3.51 or 4.0 but do not have the Windows NT 4.0 Resource Kit, follow these steps.

To change the value of the GlobalFlag, you need to modify its value in the registry.

1. Start Registry Editor (Regedt32.exe) and locate the following subkey:

   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager

2. Double-click on the GlobalFlag Value on the right pane.

3. In the Data Type field, select REG_DWORD and click OK.

4. In the Data Field, type in either 01000000 or 00000400, depending on the version of Windows NT. Select the Hex option and click OK.

         Range:   0 - 0xFFFFFFFF (not continuous)
         Default: 0
   
   

5. Quit Registry Editor, shutdown, and restart your computer.

To use this utility to enable Pool tagging:

1. Double-click on the Gflags.exe file in the resource kit directory or open a MS-DOS command prompt and type in GFLAGS and press Enter.

2. After the GFLAGS window opens, set the destination in the upper windows to System Registry.

3. In the lower portion of the window, click to select the "Enable Pool Tagging" check box.

4. The computer running Windows NT will have to be restarted for the change to take affect.

   gflags /?

MORE INFORMATION

GlobalFlag consists of 32 bits that are used as switches to enable or disable several different advanced internal system diagnostics and troubleshooting tests. For more information, see the definition of Ntexapi.h FLG_ in the Win32 Software Development Kit.

NOTE: In Windows NT versions 3.51 and earlier, changing the value of this entry to 0x20100000 disabled the OS/2 subsystem and caused OS/2-bound applications to run in a virtual DOS machine. This does not work in Windows NT 4.0.

Keywords          : ntconfig NTSrvWkst ntutil kbusage
Version           : WinNT:3.5,3.51,4.0
Platform          : winnt
Issue type        : kbprb