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PerformanceCounter Class

Represents a Windows NT performance counter component.

For a list of all members of this type, see PerformanceCounter Members.

System.Object
   System.MarshalByRefObject
      System.ComponentModel.Component
         System.Diagnostics.PerformanceCounter

[Visual Basic]
NotInheritable Public Class PerformanceCounter
   Inherits Component
   Implements ISupportInitialize
[C#]
public sealed class PerformanceCounter : Component,
   ISupportInitialize
[C++]
public __gc __sealed class PerformanceCounter : public Component,
   ISupportInitialize
[JScript]
public class PerformanceCounter extends Component implements
   ISupportInitialize

Thread Safety

This type is safe for multithreaded operations.

Remarks

The PerformanceCounter component can be used for both reading existing predefined or custom counters and publishing (writing) performance data to custom counters.

To read from a performance counter, create an instance of the PerformanceCounter class, set the CategoryName, CounterName, and, optionally, the InstanceName or MachineName properties, and then call the NextValue method to take a performance counter reading.

To publish performance counter data, create one or more custom counters using the PerformanceCounterCategory.Create method, create an instance of the PerformanceCounter class, set the CategoryName, CounterName and, optionally, InstanceName or MachineName properties, and then call the IncrementBy, Increment, or Decrement methods, or set the RawValue property to change the value of your custom counter.

The counter is the mechanism by which performance data is collected. The Registry stores the names of all the counters, each of which is related to a specific area of system functionality. Examples include a processor's busy time, memory usage, or the number of bytes received over a network connection.

Each counter is uniquely identified through its name and its location. In the same way that a file path includes a drive, a directory, one or more subdirectories, and a file name, counter information consists of four elements: the computer, the category, the category instance, and the counter name.

The counter information must include the category, or performance object, that the counter measures data for. A computer's categories include physical components, such as processors, disks, and memory. There are also system categories, such as processes and threads. Each category is related to a functional element within the computer and has a set of standard counters assigned to it. These objects are listed in the Performance object drop-down list of the Add Counters dialog box within the Windows 2000 System Monitor, and you must include them in the counter path. Performance data is grouped by the category to which is it related.

In certain cases, several copies of the same category can exist. For example, several processes and threads run simultaneously, and some computers contain more than one processor. The category copies are called category instances, and each instance has a set of standard counters assigned to it. If a category can have more than one instance, an instance specification must be included in the counter information.

To obtain performance data for counters that required an initial or previous value for performing the necessary calculation, call the NextValue method twice and use the information returned as your application requires.

Example

[Visual Basic] 
Imports System
Imports System.Collections
Imports System.Collections.Specialized
Imports System.Diagnostics

 _

Public Class App
   
   Private Shared PC As PerformanceCounter
   Private Shared BPC As PerformanceCounter
   
   
   Public Shared Sub Main()
      
      Dim samplesList As New ArrayList()
      
      SetupCategory()
      CreateCounters()
      CollectSamples(samplesList)
      CalculateResults(samplesList)
   End Sub 'Main
    
   
   
   Private Shared Function SetupCategory() As Boolean
      If Not PerformanceCounterCategory.Exists("AverageCounter64SampleCategory") Then
         
         Dim CCDC As New CounterCreationDataCollection()
         
         ' Add the counter.
         Dim averageCount64 As New CounterCreationData()
         averageCount64.CounterType = PerformanceCounterType.AverageCount64
         averageCount64.CounterName = "AverageCounter64Sample"
         CCDC.Add(averageCount64)
         
         ' Add the base counter.
         Dim averageCount64Base As New CounterCreationData()
         averageCount64Base.CounterType = PerformanceCounterType.AverageBase
         averageCount64Base.CounterName = "AverageCounter64SampleBase"
         CCDC.Add(averageCount64Base)
         
         ' Create the category.
         PerformanceCounterCategory.Create("AverageCounter64SampleCategory", "Demonstrates usage of the AverageCounter64 performance counter type.", CCDC)
         
         Return True
      Else
         Console.WriteLine("Category exists - AverageCounter64SampleCategory")
         Return False
      End If
   End Function 'SetupCategory
   
   
   Private Shared Sub CreateCounters()
      ' Create the counters.

      PC = New PerformanceCounter("AverageCounter64SampleCategory", "AverageCounter64Sample", False)
      
      BPC = New PerformanceCounter("AverageCounter64SampleCategory", "AverageCounter64SampleBase", False)
      
      
      PC.RawValue = 0
      BPC.RawValue = 0
   End Sub 'CreateCounters
   
   
   Private Shared Sub CollectSamples(samplesList As ArrayList)
      
      Dim r As New Random(DateTime.Now.Millisecond)
      
      ' Loop for the samples.
      Dim j As Integer
      For j = 0 To 99
         
         Dim value As Integer = r.Next(1, 10)
         Console.Write((j + " = " + value))
         
         PC.IncrementBy(value)
         
         BPC.Increment()
         
         If j Mod 10 = 9 Then
            OutputSample(PC.NextSample())
            samplesList.Add(PC.NextSample())
         Else
            Console.WriteLine()
         End If 
         System.Threading.Thread.Sleep(50)
      Next j
   End Sub 'CollectSamples
    
   
   Private Shared Sub CalculateResults(samplesList As ArrayList)
      Dim i As Integer
      For i = 0 To (samplesList.Count - 1) - 1
         ' Output the sample.
         OutputSample(CType(samplesList(i), CounterSample))
         OutputSample(CType(samplesList((i + 1)), CounterSample))
         
         ' Use .NET to calculate the counter value.
         Console.WriteLine((".NET computed counter value = " + CounterSampleCalculator.ComputeCounterValue(CType(samplesList(i), CounterSample), CType(samplesList((i + 1)), CounterSample))))
         
         ' Calculate the counter value manually.
         Console.WriteLine(("My computed counter value = " + MyComputeCounterValue(CType(samplesList(i), CounterSample), CType(samplesList((i + 1)), CounterSample))))
      Next i
   End Sub 'CalculateResults
   
   
   
   
   '++++++++//++++++++//++++++++//++++++++//++++++++//++++++++//++++++++//++++++++
   '    Description - This counter type shows how many items are processed, on average,
   '        during an operation. Counters of this type display a ratio of the items 
   '        processed (such as bytes sent) to the number of operations completed. The  
   '        ratio is calculated by comparing the number of items processed during the 
   '        last interval to the number of operations completed during the last interval. 
   ' Generic type - Average
   '      Formula - (N1 - N0) / (D1 - D0), where the numerator (N) represents the number 
   '        of items processed during the last sample interval and the denominator (D) 
   '        represents the number of operations completed during the last two sample 
   '        intervals. 
   '    Average (Nx - N0) / (Dx - D0)  
   '    Example PhysicalDisk\ Avg. Disk Bytes/Transfer 
   '++++++++//++++++++//++++++++//++++++++//++++++++//++++++++//++++++++//++++++++
   Private Shared Function MyComputeCounterValue(s0 As CounterSample, s1 As CounterSample) As [Single]
      Dim numerator As [Single] = CType(s1.RawValue, [Single]) - CType(s0.RawValue, [Single])
      Dim denomenator As [Single] = CType(s1.BaseValue, [Single]) - CType(s0.BaseValue, [Single])
      Dim counterValue As [Single] = numerator / denomenator
      Return counterValue
   End Function 'MyComputeCounterValue
   
   
   ' Output information about the counter sample.
   Private Shared Sub OutputSample(s As CounterSample)
      Console.WriteLine(ControlChars.Lf + ControlChars.Cr + "+++++++++++")
      Console.WriteLine("Sample values - " + ControlChars.Lf + ControlChars.Cr)
      Console.WriteLine(("   BaseValue        = " + s.BaseValue))
      Console.WriteLine(("   CounterFrequency = " + s.CounterFrequency))
      Console.WriteLine(("   CounterTimeStamp = " + s.CounterTimeStamp))
      Console.WriteLine(("   CounterType      = " + s.CounterType))
      Console.WriteLine(("   RawValue         = " + s.RawValue))
      Console.WriteLine(("   SystemFrequency  = " + s.SystemFrequency))
      Console.WriteLine(("   TimeStamp        = " + s.TimeStamp))
      Console.WriteLine(("   TimeStamp100nSec = " + s.TimeStamp100nSec))
      Console.WriteLine("++++++++++++++++++++++")
   End Sub 'OutputSample
End Class 'App

[C#] 

using System;
using System.Collections;
using System.Collections.Specialized;
using System.Diagnostics;

public class App {

    private static PerformanceCounter PC;
    private static PerformanceCounter BPC;

    public static void Main()
    {    
    
        ArrayList samplesList = new ArrayList();

        SetupCategory();
        CreateCounters();
        CollectSamples(samplesList);
        CalculateResults(samplesList);

    }
    

    private static bool SetupCategory()
    {        
        if ( !PerformanceCounterCategory.Exists("AverageCounter64SampleCategory") ) 
        {

            CounterCreationDataCollection CCDC = new CounterCreationDataCollection();
            
            // Add the counter.
            CounterCreationData averageCount64 = new CounterCreationData();
            averageCount64.CounterType = PerformanceCounterType.AverageCount64;
            averageCount64.CounterName = "AverageCounter64Sample";
            CCDC.Add(averageCount64);
            
            // Add the base counter.
            CounterCreationData averageCount64Base = new CounterCreationData();
            averageCount64Base.CounterType = PerformanceCounterType.AverageBase;
            averageCount64Base.CounterName = "AverageCounter64SampleBase";
            CCDC.Add(averageCount64Base);

            // Create the category.
            PerformanceCounterCategory.Create("AverageCounter64SampleCategory", 
                "Demonstrates usage of the AverageCounter64 performance counter type.", 
                CCDC);
                
            return(true);
        }
        else
        {
            Console.WriteLine("Category exists - AverageCounter64SampleCategory");
            return(false);
        }
    }
    
    private static void CreateCounters()
    {
        // Create the counters.

        PC = new PerformanceCounter("AverageCounter64SampleCategory", 
            "AverageCounter64Sample", 
            false);
        

        BPC = new PerformanceCounter("AverageCounter64SampleCategory", 
            "AverageCounter64SampleBase", 
            false);
        
        
        PC.RawValue=0;
        BPC.RawValue=0;
    }
    
    private static void CollectSamples(ArrayList samplesList)
    {
        
        Random r = new Random( DateTime.Now.Millisecond );

        // Loop for the samples.
        for (int j = 0; j < 100; j++) 
        {
            
            int value = r.Next(1, 10);
            Console.Write(j + " = " + value);

            PC.IncrementBy(value);

            BPC.Increment();

            if ((j % 10) == 9) 
            {
                OutputSample(PC.NextSample());
                samplesList.Add( PC.NextSample() );
            }
            else
                Console.WriteLine();
            
            System.Threading.Thread.Sleep(50);
        }

    }
    
    private static void CalculateResults(ArrayList samplesList)
    {
        for(int i = 0; i < (samplesList.Count - 1); i++)
        {
            // Output the sample.
            OutputSample( (CounterSample)samplesList[i] );
            OutputSample( (CounterSample)samplesList[i+1] );

            // Use .NET to calculate the counter value.
            Console.WriteLine(".NET computed counter value = " +
                CounterSampleCalculator.ComputeCounterValue((CounterSample)samplesList[i],
                (CounterSample)samplesList[i+1]) );

            // Calculate the counter value manually.
            Console.WriteLine("My computed counter value = " + 
                MyComputeCounterValue((CounterSample)samplesList[i],
                (CounterSample)samplesList[i+1]) );

        }
    }
    
    
    //++++++++//++++++++//++++++++//++++++++//++++++++//++++++++//++++++++//++++++++
    //    Description - This counter type shows how many items are processed, on average,
    //        during an operation. Counters of this type display a ratio of the items 
    //        processed (such as bytes sent) to the number of operations completed. The  
    //        ratio is calculated by comparing the number of items processed during the 
    //        last interval to the number of operations completed during the last interval. 
    // Generic type - Average
    //      Formula - (N1 - N0) / (D1 - D0), where the numerator (N) represents the number 
    //        of items processed during the last sample interval and the denominator (D) 
    //        represents the number of operations completed during the last two sample 
    //        intervals. 
    //    Average (Nx - N0) / (Dx - D0)  
    //    Example PhysicalDisk\ Avg. Disk Bytes/Transfer 
    //++++++++//++++++++//++++++++//++++++++//++++++++//++++++++//++++++++//++++++++
    private static Single MyComputeCounterValue(CounterSample s0, CounterSample s1)
    {
        Single numerator = (Single)s1.RawValue - (Single)s0.RawValue;
        Single denomenator = (Single)s1.BaseValue - (Single)s0.BaseValue;
        Single counterValue = numerator / denomenator;
        return(counterValue);
    }
        
    // Output information about the counter sample.
    private static void OutputSample(CounterSample s)
    {
        Console.WriteLine("\r\n+++++++++++");
        Console.WriteLine("Sample values - \r\n");
        Console.WriteLine("   BaseValue        = " + s.BaseValue);
        Console.WriteLine("   CounterFrequency = " + s.CounterFrequency);
        Console.WriteLine("   CounterTimeStamp = " + s.CounterTimeStamp);
        Console.WriteLine("   CounterType      = " + s.CounterType);
        Console.WriteLine("   RawValue         = " + s.RawValue);
        Console.WriteLine("   SystemFrequency  = " + s.SystemFrequency);
        Console.WriteLine("   TimeStamp        = " + s.TimeStamp);
        Console.WriteLine("   TimeStamp100nSec = " + s.TimeStamp100nSec);
        Console.WriteLine("++++++++++++++++++++++");
    }
}

[C++] 
#using <mscorlib.dll>
#using <System.dll>

using namespace System;
using namespace System::Collections;
using namespace System::Collections::Specialized;
using namespace System::Diagnostics;

// Output information about the counter sample.
void OutputSample(CounterSample s) {
    Console::WriteLine(S"\r\n+++++++++++");
    Console::WriteLine(S"Sample values - \r\n");
    Console::WriteLine(S"   BaseValue        = {0}", __box(s.BaseValue));
    Console::WriteLine(S"   CounterFrequency = {0}", __box(s.CounterFrequency));
    Console::WriteLine(S"   CounterTimeStamp = {0}", __box(s.CounterTimeStamp));
    Console::WriteLine(S"   CounterType      = {0}", __box(s.CounterType));
    Console::WriteLine(S"   RawValue         = {0}", __box(s.RawValue));
    Console::WriteLine(S"   SystemFrequency  = {0}", __box(s.SystemFrequency));
    Console::WriteLine(S"   TimeStamp        = {0}", __box(s.TimeStamp));
    Console::WriteLine(S"   TimeStamp100nSec = {0}", __box(s.TimeStamp100nSec));
    Console::WriteLine(S"++++++++++++++++++++++");
}

//++++++++//++++++++//++++++++//++++++++//++++++++//++++++++//++++++++//++++++++
//    Description - This counter type shows how many items are processed, on average,
//        during an operation. Counters of this type display a ratio of the items 
//        processed (such as bytes sent) to the number of operations completed. The  
//        ratio is calculated by comparing the number of items processed during the 
//        last interval to the number of operations completed during the last interval. 
// Generic type - Average
//      Formula - (N1 - N0) / (D1 - D0), where the numerator (N) represents the number 
//        of items processed during the last sample interval and the denominator (D) 
//        represents the number of operations completed during the last two sample 
//        intervals. 
//    Average (Nx - N0) / (Dx - D0)  
//    Example PhysicalDisk\ Avg. Disk Bytes/Transfer 
//++++++++//++++++++//++++++++//++++++++//++++++++//++++++++//++++++++//++++++++
float MyComputeCounterValue(CounterSample s0, CounterSample s1) {
    float numerator = (float)s1.RawValue - (float)s0.RawValue;
    float denomenator = (float)s1.BaseValue - (float)s0.BaseValue;
    float counterValue = numerator / denomenator;
    return(counterValue);
}

bool SetupCategory() {        
    if (!PerformanceCounterCategory::Exists(S"AverageCounter64SampleCategory")) {

        CounterCreationDataCollection* CCDC = new CounterCreationDataCollection();

        // Add the counter.
        CounterCreationData* averageCount64 = new CounterCreationData();
        averageCount64->CounterType = PerformanceCounterType::AverageCount64;
        averageCount64->CounterName = S"AverageCounter64Sample";
        CCDC->Add(averageCount64);

        // Add the base counter.
        CounterCreationData* averageCount64Base = new CounterCreationData();
        averageCount64Base->CounterType = PerformanceCounterType::AverageBase;
        averageCount64Base->CounterName = S"AverageCounter64SampleBase";
        CCDC->Add(averageCount64Base);

        // Create the category.
        PerformanceCounterCategory::Create(S"AverageCounter64SampleCategory", 
            S"Demonstrates usage of the AverageCounter64 performance counter type.", 
            CCDC);

        return(true);
    } else {
        Console::WriteLine(S"Category exists - AverageCounter64SampleCategory");
        return(false);
    }
}

void CreateCounters(PerformanceCounter*& PC, PerformanceCounter*& BPC) {
    // Create the counters.

    PC = new PerformanceCounter(S"AverageCounter64SampleCategory", 
        S"AverageCounter64Sample", false);
    BPC = new PerformanceCounter(S"AverageCounter64SampleCategory", 
        S"AverageCounter64SampleBase", false);

    PC->RawValue=0;
    BPC->RawValue=0;
}

void CollectSamples(ArrayList* samplesList, PerformanceCounter* PC, PerformanceCounter* BPC) {

    Random* r = new Random(DateTime::Now.Millisecond);

    // Loop for the samples.
    for (int j = 0; j < 100; j++) {

        int value = r->Next(1, 10);
        Console::Write(S"{0} = {1}", __box(j), __box(value));

        PC->IncrementBy(value);

        BPC->Increment();

        if ((j % 10) == 9) {
            OutputSample(PC->NextSample());
            samplesList->Add(__box(PC->NextSample()));
        } else
            Console::WriteLine();

        System::Threading::Thread::Sleep(50);
    }
}

void CalculateResults(ArrayList* samplesList) {
    for (int i = 0; i < (samplesList->Count - 1); i++) {
        // Output the sample.
        OutputSample(*__try_cast<__box CounterSample*>(samplesList->Item[i]));
        OutputSample(*__try_cast<__box CounterSample*>(samplesList->Item[i+1]));

        // Use .NET to calculate the counter value.
        Console::WriteLine(S".NET computed counter value = {0}",
            __box(CounterSampleCalculator::ComputeCounterValue(
            *__try_cast<__box CounterSample*>(samplesList->Item[i]), 
            *__try_cast<__box CounterSample*>(samplesList->Item[i+1]))));

        // Calculate the counter value manually.
        Console::WriteLine(S"My computed counter value = {0}", 
            __box(MyComputeCounterValue(
            *__try_cast<__box CounterSample*>(samplesList->Item[i]),
            *__try_cast<__box CounterSample*>(samplesList->Item[i+1]))));
    }
}

int main() {    
    ArrayList* samplesList = new ArrayList();
    PerformanceCounter* PC;
    PerformanceCounter* BPC;

    SetupCategory();
    CreateCounters(PC, BPC);
    CollectSamples(samplesList, PC, BPC);
    CalculateResults(samplesList);
}

[JScript] No example is available for JScript. To view a Visual Basic, C#, or C++ example, click the Language Filter button Language Filter in the upper-left corner of the page.

Requirements

Namespace: System.Diagnostics

Platforms: Windows NT Server 4.0, Windows NT Workstation 4.0, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family

Assembly: System (in System.dll)

See Also

PerformanceCounter Members | System.Diagnostics Namespace | PerformanceCounterType | CounterCreationData | CounterCreationDataCollection | CounterSample | CounterSampleCalculator

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