[THIN] KB: Terminal Services Performance Problem Because of Contention on CmpRegistryLock
- From: Jim Kenzig <jimkenz@xxxxxxxxxxxxxx>
- To: thin@xxxxxxxxxxxxx
- Date: Tue, 3 Sep 2002 16:08:13 -0400
Knowledge Base
Terminal Services Performance Problem Because of Contention on
CmpRegistryLock
PSS ID Number: Q317357
Article Last Modified on 07-31-2002
The information in this article applies to:
* Microsoft Windows 2000, 2000 SP1, 2000 SP2 Server
* Microsoft Windows 2000, 2000 SP1, 2000 SP2 Advanced Server
IMPORTANT: This article contains information about modifying the registry.
Before you modify the registry, make sure to back it up and make sure that
you understand how to restore the registry if a problem occurs. For
information about how to back up, restore, and edit the registry, click the
following article number to view the article in the Microsoft Knowledge
Base:
Q256986 Description of the Microsoft Windows Registry
Symptoms
When 50-100 interactive Terminal Services users are logged on, and other
Terminal Services users are logging on or off at the same time, your
computer may become irresponsive for about 10-30 seconds. The frequency of
this symptom is variable, but can occur 10-20 times a day. When this problem
occurs, the mouse and keyboard do not respond, but the computer is
responsive on the network (to ping and net use commands), and on the
console.
Notes
You can determine that you are experiencing this problem by running
Perfmon.exe locally. Perfmon.exe show a series of intervals of "system
inactivity", when all counters drop to zero (0). During this interval, you
may notice heavy system disk activity. This behavior is not specific to any
one computer manufacturer or model, and may potentially affect all Windows
2000 installations, especially those that are using Terminal Services.
Terminal Services is an "enabler" for this performance problem, because of
the total size of the registry hives that are associated with all of the
Terminal Services sessions that are in progress. This problem can occur when
there is plenty of available memory.
Cause
This performance problem may be caused by a slowdown that is caused by the
number of input/outputs on the system disk during the registry-flush
operation. The "system inactivity" intervals you see in Perfmon.exe occur
because of contention on the CmpRegistryLock, which protects against
registry writers (such as Perfmon.exe and Explorer.exe) during the
hive-flush operation.
NOTE: This input/output slowdown was noted to occur even though the computer
had plenty of available memory. If you computer does not have enough memory,
performance may be substantially degraded before you can see the
input/output slowdown.
Resolution
To resolve this problem, obtain the latest service pack for Windows 2000.
For additional information, click the following article number to view the
article in the Microsoft Knowledge Base:
Q260910 How to Obtain the Latest Windows 2000 Service Pack
The English version of this fix should have the following file attributes or
later:
Date Time Size File name
-----------------------------------------
26-Feb-02 23:34 1,686,976 Ntkrnlmp.exe
26-Feb-02 23:35 1,686,720 Ntkrnlpa.exe
26-Feb-02 23:35 1,707,392 Ntkrpamp.exe
26-Feb-02 23:34 1,664,640 Ntoskrnl.exe
WARNING: If you use Registry Editor incorrectly, you may cause serious
problems that may require you to reinstall your operating system. Microsoft
cannot guarantee that you can solve problems that result from using Registry
Editor incorrectly. Use Registry Editor at your own risk.
You can use the following registry key to reduce the registry-flush
frequency so that registry modifications can accumulate before the flush. To
do so, follow these steps:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager
Start Registry Editor (Regedt32.exe).
Locate and then click the following key in the registry:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager
On the Edit menu, click Add Key, and then add the following registry
value:
Key Name: Configuration Manager
Click the Configuration Manager key.
On the Edit menu, click Add Value, and then add the following registry
value:
Value name: RegistryLazyFlushInterval
Data type: REG_DWORD
Radix: Decimal
Value data: time in seconds (default value is 5).
Quit Registry Editor.
NOTE: The default setting for the RegistryLazyFlushInterval value is the
same as in Windows 2000 and previous versions of Windows.
Tune for Performance
A reduction of the number of registry-flush operations, by a factor of 2-3,
was measured for values of 30-60 seconds of this interval.
Tune Suggestion
Perform a comparative test with the interval set to 30 seconds, and then to
60 seconds. If the observed performance is about the same, select the value
of 30 seconds. If the observed difference of performance is important,
select a higher value that is closer to 60 seconds. Note that no performance
enhancements are noticed when you use an interval that is higher than 60
seconds.
Workaround
To work around this problem, use either of the following methods.
* Enhance system disk-write performance, and turn on write-back caching.
* If you can, reduce the size of user profiles.
Status
Microsoft has confirmed that this is a problem in the Microsoft products
that are listed at the beginning of this article. This problem was first
corrected in Windows 2000 Service Pack 3.
More Information
For additional information about how to obtain a hotfix for Windows 2000
Datacenter Server, click the article number below to view the article in the
Microsoft Knowledge Base:
Q265173 The Datacenter Program and Windows 2000 Datacenter Server
Product
For additional information about how to install multiple hotfixes with only
one reboot, click the article number below to view the article in the
Microsoft Knowledge Base:
Q296861 Use QChain.exe to Install Multiple Hotfixes with One Reboot
Additional query words: kbBaseOS temporary hangs bottleneck
Keywords: kbWin2000PreSP3Fix kbWin2000sp3fix
Issue Type: kbbug
Technology: kbwin2000AdvServ kbwin2000AdvServSearch kbwin2000Serv
kbwin2000ServSearch kbwin2000Search kbWinAdvServSearch kbWin2000AdvServSP2
kbWin2000AdvServSP1 kbwin2000ServSP1 kbwin2000ServSP2
Send feedback to Microsoft <JavaScript:sendfeedback('Q317357',
'TECHNET@xxxxxxxxxxxxx')>
© 2002 Microsoft Corporation. All rights reserved.
**********************************************
This weeks sponsor 99Point9.com
99Point9 helps solve your unresolved technical
server-based questions, issues and incidents.
http://www.99point9.com
***********************************************
For Archives, to Unsubscribe, Subscribe or
set Digest or Vacation mode use the below link.
http://thethin.net/citrixlist.cfm
Other related posts:
- » [THIN] KB: Terminal Services Performance Problem Because of Contention on CmpRegistryLock
