Important This article contains information about how to modify the registry. Make sure to back up the registry before you modify it. Make sure that you know how to restore the registry if a problem occurs. For more information about how to back up, restore, and modify the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986 Description of the Microsoft Windows registry

Symptoms

When you use a Microsoft Windows Server 2003 or Microsoft Windows Server 2008-based computer that has more than 32 processors, you may notice that many events are reported in the System log that resemble the following:

Event logged:
===============
PerfOS event ID: 2001 - "Unable to get interrupt information from system."

Cause

This problem occurs because one or more 32-bit applications have used the NtQuerySystemInformation function in order to determine the number of processors that are available for the computer. If more than 32 processors are available, the PerfOS event is logged every time that the NtQuerySystemInformation function is used.

Resolution

Windows Server 2003-based computers that are running Service Pack 2 (SP2)

Warning Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall your operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk.

This problem was addressed in Windows Server 2003 Service Pack 2 (SP2). You do not have to download a hotfix to resolve this problem. However, some Windows registry information is missing. To resolve this problem, you must modify the Windows registry. To do this, follow these steps:

  1. Click Start, click Run, type regedit, and then click
    OK.

  2. Locate and then click the following registry key:

    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\PerfOS\Performance

  3. In the Edit menu, point to
    New, click DWORD Value, type
    LogErrorToFile, and then press ENTER.

  4. Double-click LogErrorToFile, type
    0, and then click OK.

    Note When you set the LogErrorToFile value to 0, PerfOS events are no longer logged in the System log. You can enable logging again by setting this value to 1.

Hotfix information

Service pack information for Windows Server 2003

To resolve this problem, obtain the latest service pack for Windows Server 2003. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

889100 How to obtain the latest service pack for Windows Server 2003 A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site:

http://support.microsoft.com/contactus/?ws=supportNote The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.

Windows Server 2003-based computers that are running Service Pack 1 (SP1) or earlier versions

When you install this hotfix on computers that are running Service Pack 1 (SP1) or earlier versions, you do not have to modify the registry to resolve this problem.

Prerequisites

There are no prerequisites for installing this hotfix.

Restart requirement

You must restart your computer after you apply this hotfix.

Hotfix replacement information


This hotfix does not replace any other hotfixes.

File information

The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.

Windows Server 2003, Itanium-based computers that are running SP1 or earlier versions

File name

File version

File size

Date

Time

Platform

SP requirement

Service branch

Perfos.dll

5.2.3790.2794

57,344

16-Sep-2006

14:28

IA-64

SP1

SP1QFE

Wperfos.dll

5.2.3790.2794

27,136

16-Sep-2006

14:28

x86

SP1

WOW

Updspapi.dll

6.2.29.0

638,688

16-Sep-2006

14:39

IA-64

None

Not Applicable

Windows Server 2003, x64-based computers that are running SP1 or earlier versions

File name

File version

File size

Date

Time

Platform

SP requirement

Service branch

Perfos.dll

5.2.3790.2794

32,256

16-Sep-2006

14:28

x64

SP1

SP1QFE

Wperfos.dll

5.2.3790.2794

27,136

16-Sep-2006

14:28

x86

SP1

WOW

Updspapi.dll

6.2.29.0

462,048

16-Sep-2006

14:39

x64

None

Not Applicable

Windows Server 2003, x86-based computers that are running SP1 or earlier versions

File name

File version

File size

Date

Time

Platform

Perfos.dll

5.2.3790.2794

27,136

16-Sep-2006

12:50

x86

Updspapi.dll

6.2.29.0

371,424

12-Oct-2005

23:13

x86

Service pack information for Windows Server 2008

Note This bug is fixed when you install this hotfix on Windows Server 2008 or on Windows Server 2008 SP2. Therefore, you do not have to modify the registry entry on Windows Server 2008 or on Windows Server 2008 SP2.

Prerequisites

There are no prerequisites for installing this hotfix.

Restart requirement

You must restart your computer after you apply this hotfix.

Hotfix replacement information


This hotfix does not replace any other hotfixes.

File information

The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.

Windows Server 2008, Itanium-based computers

File name

File version

File size

Date

Time

Platform

Perfctrs.dll

6.0.6001.22467

84,992

10-Jul-2009

11:57

IA-64

Perfdisk.dll

6.0.6001.22467

72,704

10-Jul-2009

11:57

IA-64

Perfnet.dll

6.0.6001.22467

47,104

10-Jul-2009

11:57

IA-64

Perfos.dll

6.0.6001.22467

61,440

10-Jul-2009

11:57

IA-64

Perfproc.dll

6.0.6001.22467

77,824

10-Jul-2009

11:57

IA-64

Perfctrs.dll

6.0.6002.22169

84,992

10-Jul-2009

11:42

IA-64

Perfdisk.dll

6.0.6002.22169

72,704

10-Jul-2009

11:42

IA-64

Perfnet.dll

6.0.6002.22169

47,104

10-Jul-2009

11:42

IA-64

Perfos.dll

6.0.6002.22169

61,440

10-Jul-2009

11:42

IA-64

Perfproc.dll

6.0.6002.22169

77,824

10-Jul-2009

11:42

IA-64

Perfctrs.dll

6.0.6001.22467

39,424

10-Jul-2009

11:58

x86

Perfdisk.dll

6.0.6001.22467

31,744

10-Jul-2009

11:58

x86

Perfnet.dll

6.0.6001.22467

19,968

10-Jul-2009

11:58

x86

Perfos.dll

6.0.6001.22467

28,672

10-Jul-2009

11:58

x86

Perfproc.dll

6.0.6001.22467

35,840

10-Jul-2009

11:58

x86

Perfctrs.dll

6.0.6002.22169

39,424

10-Jul-2009

11:49

x86

Perfdisk.dll

6.0.6002.22169

31,744

10-Jul-2009

11:49

x86

Perfnet.dll

6.0.6002.22169

19,968

10-Jul-2009

11:49

x86

Perfos.dll

6.0.6002.22169

28,672

10-Jul-2009

11:49

x86

Perfproc.dll

6.0.6002.22169

35,840

10-Jul-2009

11:49

x86


Windows Server 2008, x64-based computers

File name

File version

File size

Date

Time

Platform

Perfctrs.dll

6.0.6001.22467

43,520

10-Jul-2009

12:26

x64

Perfdisk.dll

6.0.6001.22467

35,328

10-Jul-2009

12:26

x64

Perfnet.dll

6.0.6001.22467

23,040

10-Jul-2009

12:26

x64

Perfos.dll

6.0.6001.22467

29,696

10-Jul-2009

12:26

x64

Perfproc.dll

6.0.6001.22467

37,888

10-Jul-2009

12:26

x64

Perfctrs.dll

6.0.6002.22169

43,520

10-Jul-2009

11:55

x64

Perfdisk.dll

6.0.6002.22169

35,328

10-Jul-2009

11:55

x64

Perfnet.dll

6.0.6002.22169

23,040

10-Jul-2009

11:55

x64

Perfos.dll

6.0.6002.22169

29,696

10-Jul-2009

11:55

x64

Perfproc.dll

6.0.6002.22169

37,888

10-Jul-2009

11:55

x64

Perfctrs.dll

6.0.6001.22467

39,424

10-Jul-2009

11:58

x86

Perfdisk.dll

6.0.6001.22467

31,744

10-Jul-2009

11:58

x86

Perfnet.dll

6.0.6001.22467

19,968

10-Jul-2009

11:58

x86

Perfos.dll

6.0.6001.22467

28,672

10-Jul-2009

11:58

x86

Perfproc.dll

6.0.6001.22467

35,840

10-Jul-2009

11:58

x86

Perfctrs.dll

6.0.6002.22169

39,424

10-Jul-2009

11:49

x86

Perfdisk.dll

6.0.6002.22169

31,744

10-Jul-2009

11:49

x86

Perfnet.dll

6.0.6002.22169

19,968

10-Jul-2009

11:49

x86

Perfos.dll

6.0.6002.22169

28,672

10-Jul-2009

11:49

x86

Perfproc.dll

6.0.6002.22169

35,840

10-Jul-2009

11:49

x86


Windows Server 2008, x86-based computers

File name

File version

File size

Date

Time

Platform

Perfctrs.dll

6.0.6001.22467

39,424

10-Jul-2009

11:58

x86

Perfdisk.dll

6.0.6001.22467

31,744

10-Jul-2009

11:58

x86

Perfnet.dll

6.0.6001.22467

19,968

10-Jul-2009

11:58

x86

Perfos.dll

6.0.6001.22467

28,672

10-Jul-2009

11:58

x86

Perfproc.dll

6.0.6001.22467

35,840

10-Jul-2009

11:58

x86

Perfctrs.dll

6.0.6002.22169

39,424

10-Jul-2009

11:49

x86

Perfdisk.dll

6.0.6002.22169

31,744

10-Jul-2009

11:49

x86

Perfnet.dll

6.0.6002.22169

19,968

10-Jul-2009

11:49

x86

Perfos.dll

6.0.6002.22169

28,672

10-Jul-2009

11:49

x86

Perfproc.dll

6.0.6002.22169

35,840

10-Jul-2009

11:49

x86

Status

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section. This problem was first corrected in Windows Server 2003 Service Pack 2.

More Information

For more information, click the following article number to view the article in the Microsoft Knowledge Base:

824684 Description of the standard terminology that is used to describe Microsoft software updates

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