PerformanceCounter Class

The PerformanceCounter class in the System.Diagnostics namespace provides a managed wrapper for Windows performance counter objects. It allows you to read performance data from the operating system, such as CPU utilization, memory usage, disk I/O, and custom application-specific counters.

Namespace:

System.Diagnostics

Assembly:

System.dll

Syntax:

public sealed class PerformanceCounter

Remarks:

Performance counters are a powerful tool for monitoring the health and performance of your applications and the underlying system. The PerformanceCounter class simplifies the process of interacting with these counters.

You can create a PerformanceCounter instance by specifying the counter category, the counter name, and optionally the instance name. If the counter is a single instance counter, the instance name can be an empty string. For multi-instance counters, you need to provide the specific instance name.

The PerformanceCounter class supports both built-in system counters and custom counters that you can create and expose from your application.

Note: Accessing performance counters typically requires appropriate permissions. Ensure your application has the necessary privileges to read performance data.

Constructors:

Constructor	Description
`PerformanceCounter()`	Initializes a new instance of the `PerformanceCounter` class with default settings.
`PerformanceCounter(string categoryName, string counterName)`	Initializes a new instance of the `PerformanceCounter` class, specifying the counter category and name.
`PerformanceCounter(string categoryName, string counterName, string instanceName)`	Initializes a new instance of the `PerformanceCounter` class, specifying the counter category, name, and instance name.
`PerformanceCounter(string categoryName, string counterName, string instanceName, bool readOnly)`	Initializes a new instance of the `PerformanceCounter` class, specifying the counter category, name, instance name, and whether it should be read-only.

Properties:

Property	Description
`CategoryName`	Gets the name of the performance counter category.
`CounterName`	Gets the name of the performance counter.
`InstanceName`	Gets the name of the performance counter instance.
`ReadOnly`	Gets a value indicating whether the performance counter is read-only.
`RawValue`	Gets or sets the raw value of the performance counter.
`CookedValue`	Gets the counter's value, formatted for display.
`CounterHelp`	Gets the help text for the performance counter.

Methods:

Method	Description
`Increment()`	Increments the value of a counter by one.
`IncrementBy(long value)`	Increments the value of a counter by the specified amount.
`Decrement()`	Decrements the value of a counter by one.
`NextValue()`	Retrieves the next sampled value of the performance counter.
`NextSample()`	Retrieves the next sample for the performance counter.
`Close()`	Releases all resources used by the `PerformanceCounter`.
`Dispose()`	Releases all resources used by the `PerformanceCounter`.

Example:

The following example demonstrates how to read the current CPU utilization:

using System;
using System.Diagnostics;

public class CpuMonitor
{
    public static void Main(string[] args)
    {
        try
        {
            // Create a PerformanceCounter instance for CPU utilization
            // Category: Processor, Counter: % Processor Time, Instance: _Total
            PerformanceCounter cpuCounter = new PerformanceCounter(
                "Processor",
                "% Processor Time",
                "_Total",
                true); // Read-only

            // Get the initial value to establish a baseline
            cpuCounter.NextValue();

            // Wait for a short period
            System.Threading.Thread.Sleep(1000);

            // Get the current CPU utilization
            float cpuUsage = cpuCounter.NextValue();

            Console.WriteLine($"Current CPU Usage: {cpuUsage:N2}%");

            cpuCounter.Dispose(); // Release resources
        }
        catch (InvalidOperationException ex)
        {
            Console.WriteLine($"Error accessing performance counter: {ex.Message}");
            Console.WriteLine("Ensure the 'Processor' category and '% Processor Time' counter exist and you have permissions.");
        }
        catch (Exception ex)
        {
            Console.WriteLine($"An unexpected error occurred: {ex.Message}");
        }
    }
}

Tip: You can use the Performance Monitor (perfmon.msc) utility in Windows to explore available performance counter categories and counters on your system.

MSDN