DOCUMENT:Q110954  04-FEB-1994  [W_NT]
TITLE   :Performance Monitor CPU Utilization May Be Incorrect
PRODUCT :Windows NT
PROD/VER:3.10
OPER/SYS:WINDOWS
KEYWORDS:

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The information in this article applies to:

 - Microsoft Windows NT operating system version 3.1
 - Microsoft Windows NT Advanced Server version 3.1
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SUMMARY
=======

Performance Monitor does not correctly calculate CPU Idle time for 16-bit
applications.

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

When you monitor the Percent Total Processor Time counter under the System
object in Performance Monitor and a 16-bit application is the current
window, Performance Monitor incorrectly reports processor usage at 100
percent.

The documentation for Performance Monitor says that Percent Total Processor
Time is the average percentage of time that all the processors on the
system are busy executing non-idle threads. When a 16-bit application is
the current window, however, this counter totals the busy and idle time
together, which makes the results almost meaningless.

Steps to Reproduce Problem
--------------------------

(NOTE: This test requires the QSLICE.EXE program from the Windows NT
Resource Kit. You can also reproduce this problem by using Performance
Monitor and adding the Percent Total Processor Time counter under the
System object.)

1. Start QSLICE and WRITE, arranging both windows so that they are visible
   on the screen at the same time.

2. Monitor the NTVDM.EXE entry in QSLICE. If you do nothing in WRITE, this
   counter shows little or no processor activity.

3. Type some text into WRITE and notice that the CPU utilization for NTVDM
   jumps upwards.

This CPU utilization stays high until you move the focus away from WRITE.
Even if you do not type anything, and WRITE is essentially idle, this
utilization stays high. This is incorrect.

Microsoft has confirmed this to be a problem in Windows NT and Windows
NT Advanced Server version 3.1.  We are researching this problem and
will post new information here in the Microsoft Knowledge Base as it
becomes available.

Additional reference words: 3.10 perfmon
KBCategory:
KBSubCategory: 32ap


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