PerformanceCounter Class

Represents a Windows NT performance counter component.

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

Namespace:  System.Diagnostics
Assembly:  System (in System.dll)

[HostProtectionAttribute(SecurityAction.LinkDemand, Synchronization = true, 
	SharedState = true)]
public sealed class PerformanceCounter : Component, 
	ISupportInitialize

The PerformanceCounter type exposes the following members.

  NameDescription
Public methodPerformanceCounter()Initializes a new, read-only instance of the PerformanceCounter class, without associating the instance with any system or custom performance counter.
Public methodPerformanceCounter(String, String)Initializes a new, read-only instance of the PerformanceCounter class and associates it with the specified system or custom performance counter on the local computer. This constructor requires that the category have a single instance.
Public methodPerformanceCounter(String, String, Boolean)Initializes a new, read-only or read/write instance of the PerformanceCounter class and associates it with the specified system or custom performance counter on the local computer. This constructor requires that the category contain a single instance.
Public methodPerformanceCounter(String, String, String)Initializes a new, read-only instance of the PerformanceCounter class and associates it with the specified system or custom performance counter and category instance on the local computer.
Public methodPerformanceCounter(String, String, String, Boolean)Initializes a new, read-only or read/write instance of the PerformanceCounter class and associates it with the specified system or custom performance counter and category instance on the local computer.
Public methodPerformanceCounter(String, String, String, String)Initializes a new, read-only instance of the PerformanceCounter class and associates it with the specified system or custom performance counter and category instance, on the specified computer.
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  NameDescription
Public propertyCategoryNameGets or sets the name of the performance counter category for this performance counter.
Public propertyContainerGets the IContainer that contains the Component. (Inherited from Component.)
Public propertyCounterHelpGets the description for this performance counter.
Public propertyCounterNameGets or sets the name of the performance counter that is associated with this PerformanceCounter instance.
Public propertyCounterTypeGets the counter type of the associated performance counter.
Public propertyInstanceLifetimeGets or sets the lifetime of a process.
Public propertyInstanceNameGets or sets an instance name for this performance counter.
Public propertyMachineNameGets or sets the computer name for this performance counter
Public propertyRawValueGets or sets the raw, or uncalculated, value of this counter.
Public propertyReadOnlyGets or sets a value indicating whether this PerformanceCounter instance is in read-only mode.
Public propertySiteGets or sets the ISite of the Component. (Inherited from Component.)
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  NameDescription
Public methodBeginInitBegins the initialization of a PerformanceCounter instance used on a form or by another component. The initialization occurs at runtime.
Public methodCloseCloses the performance counter and frees all the resources allocated by this performance counter instance.
Public methodStatic memberCloseSharedResourcesFrees the performance counter library shared state allocated by the counters.
Public methodCreateObjRefCreates an object that contains all the relevant information required to generate a proxy used to communicate with a remote object. (Inherited from MarshalByRefObject.)
Public methodDecrementDecrements the associated performance counter by one through an efficient atomic operation.
Public methodDispose()Releases all resources used by the Component. (Inherited from Component.)
Public methodEndInitEnds the initialization of a PerformanceCounter instance that is used on a form or by another component. The initialization occurs at runtime.
Public methodEquals(Object)Determines whether the specified object is equal to the current object. (Inherited from Object.)
Public methodGetHashCodeServes as the default hash function. (Inherited from Object.)
Public methodGetLifetimeServiceRetrieves the current lifetime service object that controls the lifetime policy for this instance. (Inherited from MarshalByRefObject.)
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Public methodIncrementIncrements the associated performance counter by one through an efficient atomic operation.
Public methodIncrementByIncrements or decrements the value of the associated performance counter by a specified amount through an efficient atomic operation.
Public methodInitializeLifetimeServiceObtains a lifetime service object to control the lifetime policy for this instance. (Inherited from MarshalByRefObject.)
Public methodNextSampleObtains a counter sample, and returns the raw, or uncalculated, value for it.
Public methodNextValueObtains a counter sample and returns the calculated value for it.
Public methodRemoveInstanceDeletes the category instance specified by the PerformanceCounter object InstanceName property.
Public methodToStringReturns a String containing the name of the Component, if any. This method should not be overridden. (Inherited from Component.)
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  NameDescription
Public eventDisposedOccurs when the component is disposed by a call to the Dispose method. (Inherited from Component.)
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  NameDescription
Public fieldStatic memberDefaultFileMappingSize Obsolete. Specifies the size, in bytes, of the global memory shared by performance counters. The default size is 524,288 bytes.
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The PerformanceCounter component can be used for both reading existing predefined or custom counters and publishing (writing) performance data to custom counters.

There are numerous predefined counters listed in the Windows Performance Monitor's Add Counters dialog box. To learn about the .NET Framework performance counters, see Performance Counters in the .NET Framework.

This type implements the IDisposable interface. When you have finished using the type, you should dispose of it either directly or indirectly. To dispose of the type directly, call its Dispose method in a try/catch block. To dispose of it indirectly, use a language construct such as using (in C#) or Using (in Visual Basic). For more information, see the “Using an Object that Implements IDisposable” section in the IDisposable interface topic.

Important noteImportant

In versions 1.0 and 1.1 of the .NET Framework, this class requires immediate callers to be fully trusted. Starting with the .NET Framework version 2.0, this class requires PerformanceCounterPermission for specific actions. It is strongly recommended that PerformanceCounterPermission not be granted to semi-trusted code. The ability to read and write performance counters allows code to perform actions such as enumerating executing processes and obtaining information about them.

In addition, passing a PerformanceCounter object to less-trusted code can create a security issue. Never pass performance counter objects, such as a PerformanceCounterCategory or PerformanceCounter, to less trusted code.

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.

NoteNote

The Increment, IncrementBy, and Decrement methods use interlocks to update the counter value. This helps keep the counter value accurate in multithreaded or multiprocess scenarios, but also results in a performance penalty. If you do not need the accuracy that interlocked operations provide, you can update the RawValue property directly for up to a 5 times performance improvement. However, in multithreaded scenarios, some updates to the counter value might be ignored, resulting in inaccurate data.

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.

NoteNote

Performance counter categories installed with the .NET Framework 2.0 use separate shared memory, with each performance counter category having its own memory. You can specify the size of separate shared memory by creating a DWORD named FileMappingSize in the registry key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\<category name>\Performance. The FileMappingSize value is set to the shared memory size of the category. The default size is 131072 decimal. If the FileMappingSize value is not present, the fileMappingSize attribute value for the performanceCounters element specified in the Machine.config file is used, causing additional overhead for configuration file processing. You can realize a performance improvement for application startup by setting the file mapping size in the registry. For more information about the file mapping size, see <performanceCounters> Element.

NoteNote

The HostProtectionAttribute attribute applied to this type or member has the following Resources property value: Synchronization | SharedState. The HostProtectionAttribute does not affect desktop applications (which are typically started by double-clicking an icon, typing a command, or entering a URL in a browser). For more information, see the HostProtectionAttribute class or SQL Server Programming and Host Protection Attributes.

Windows 98, Windows Millennium Edition Platform Note: Performance counters are not supported on Windows 98 or Windows Millennium Edition (Me).

The following code example demonstrates the use of the PerformanceCounter class to create and use an AverageCount64 counter type. The example creates categories, sets up counters, collects data from the counters, and calls the CounterSampleCalculator class to interpret the performance counter data. The intermediate and final results are displayed in the console window. For additional examples of other performance counter types, see the PerformanceCounterType enumeration.


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

public class App {

	private static PerformanceCounter avgCounter64Sample;
	private static PerformanceCounter avgCounter64SampleBase;

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

        // If the category does not exist, create the category and exit. 
        // Performance counters should not be created and immediately used. 
        // There is a latency time to enable the counters, they should be created 
        // prior to executing the application that uses the counters. 
        // Execute this sample a second time to use the category. 
        if (SetupCategory())
            return;
		CreateCounters();
		CollectSamples(samplesList);
		CalculateResults(samplesList);

	}
	

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

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

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

		avgCounter64Sample = new PerformanceCounter("AverageCounter64SampleCategory", 
			"AverageCounter64Sample", 
			false);
		

		avgCounter64SampleBase = new PerformanceCounter("AverageCounter64SampleCategory", 
			"AverageCounter64SampleBase", 
			false);
		
		
		avgCounter64Sample.RawValue=0;
		avgCounter64SampleBase.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);

			avgCounter64Sample.IncrementBy(value);

			avgCounter64SampleBase.Increment();

			if ((j % 10) == 9) 
			{
				OutputSample(avgCounter64Sample.NextSample());
				samplesList.Add( avgCounter64Sample.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("++++++++++++++++++++++");
	}
}

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
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