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Q169901: Perfmon: Processor Spikes on Multiprocessor Computer

Article: Q169901
Product(s): Microsoft Windows NT
Version(s): winnt:3.51,4.0
Operating System(s): 
Keyword(s): kbbuglist
Last Modified: 09-AUG-2001

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The information in this article applies to:

- Microsoft Windows NT Workstation versions 3.51, 4.0 
- Microsoft Windows NT Server versions 3.51, 4.0 
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SYMPTOMS
========

On a multiprocessor computer, you may see periods where the processor usage
percentage will spike to 100 percent and back to 0 percent. This spike may
happen for an unspecified period of time and then it may return to normal. This
spike will happen on all processors in the computer at the same time.

CAUSE
=====

When Window NT queries a server for performance data, it uses a software timer
that is shared among all the processors. On certain multiprocessor computers,
this might report a time that is not properly synchronized with another
processor. Therefore, the time counter occasionally becomes out of synch,
causing the perfmon data to oscillate between a large positive and large
negative number. This problem has only been seen, so far, on computers that are
based on the Intel Multiprocessor Architecture.


STATUS
======

Microsoft has confirmed this to be a problem in Microsoft Windows NT version
4.0. This problem was corrected in the latest Microsoft Windows NT 4.0 U.S.
Service Pack. For information on obtaining the service pack, query on the
following word in the Microsoft Knowledge Base (without the spaces):

  S E R V P A C K


MORE INFORMATION
================

For the fix to work correctly, it must be able to determine that it should use
the 8254 chip to use as its base timer. On newer BIOS, there will be a table
entry that the HAL will look at while initializing. On computers without a newer
BIOS, you will have to add a /USE8254 to the appropriate line in the Boot.ini
file.

Additional query words: peak peaks spike

======================================================================
Keywords          :  kbbuglist
Technology        : kbWinNTsearch kbWinNTWsearch kbWinNTW400 kbWinNTW400search kbWinNT351search kbWinNT400search kbWinNTW351search kbWinNTW351 kbWinNTSsearch kbWinNTS400search kbWinNTS400 kbWinNTS351 kbWinNTS351search
Version           : winnt:3.51,4.0
Hardware          : ALPHA x86
Issue type        : kbbug

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