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How Do I...Count rate of change?
Windows performance counters enable
your applications and components to publish, capture, and analyze the
performance data that applications, services, and drivers provide. You can use
this information to determine system bottlenecks and fine-tune system and
application performance. For example, you can use a performance counter to
track the number of orders processes per second or the number of users currently
connected to the system. Using the common language runtime's PerformanceCounter
component, you can easily create your own custom counters and publish
performance data relevant to your application, such as those mentioned above.
This sample illustrates how to publish the number of orders processed per second using a
custom performance counter. It's a small console application you can run
from the command prompt.
You have to run the app first to install the counter as follows:
> PCDemo.exe /inst
Then you have to run the app again without any arguments to see it work as follows:
> PCDemo.exe
Now, wait for the application to display "Started" and run the PerfMon.exe.
In PerfMon, choose the Add toolbar button. A dialog will open.
Select the ACounterDemo performance object, CountPerSecond
counter, and _Total instance. Choose Add, close the
dialog, and notice that you can use the PCDemo sample to change the published
value by pressing + or -. When the application starts,
it simulates the processing of two new orders per
second. The + and - keys can be used to double the number or divide it in two.
To delete the counter you could run the app with the delete switch as follows:
> PCDemo.exe /del
In its simplest form, writing to a custom performance counter that counts number of
items per second involves:
- Creating a counter of the RateOfCountsPerSecond32 type:
If Not PerformanceCounterCategory.Exists(objectName) Then
Dim ccd As CounterCreationData = new CounterCreationData()
ccd.CounterName = counterName
ccd.CounterType = PerformanceCounterType.RateOfCountsPerSecond32
Dim ccds As New CounterCreationDataCollection
ccds.Add(ccd)
PerformanceCounterCategory.Create(objectName,"Sample Object",ccds)
End If
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- Creating a new instance of a PerformanceCounter component and pointing it to an appropriate performance
counter:
Dim objectName As String = ...
Dim counterName As String = ...
Dim instanceName As String = ...
Dim counter As PerformanceCounter
counter = New PerformanceCounter(objectName, counterName, instanceName)
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- Setting the RawValue property of the counter:
Example
VB PCDemo.exe
Microsoft .NET Framework SDK QuickStart Tutorials Version 2.0
Copyright � 2005 Microsoft Corporation. All rights reserved.
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