Performance Counters in .Net

Introduction

Performance counters allow us to monitor physical devices such as Processor, Memory, CLR, Network, Threads etc. Windows provides performance monitor utility to view performance counters. To open that utility need to go to Start -> Run and type “perfmon” and press enter. Below is the screenshot of Performance Monitor utility.

This application monitors various system components, as per above image it displays the processor time utilization. There are multiple performance counters available to monitor different devices. Those performance counters are grouped under categories. Below screenshot displays Add Counter window of performance monitor utility.

Above image displays various categories like Processor, Process, Print Queue, Power Meter etc. Each category has its own counters, as per above image Processor category has “% C1 Time”, “% C2 Time” and so on. Category may have instances and if it has then it will be displayed in instance list. Instance list of selected category is available below the category list. 

Enumerating available categories

Dotnet provides PerformanceCounterCategory class to get all the categories of performance counters. This class is available in System.Diagnostics namespace. GetCategories methods returns collection of PerformanceCounterCategory. Let’s have a look on below code.

//Get all performance categories

PerformanceCounterCategory[] perfCats = PerformanceCounterCategory.GetCategories();

foreach (PerformanceCounterCategory category in perfCats.OrderBy(c => c.CategoryName))

{

    Console.WriteLine("Category Name: {0}", category.CategoryName);

}

Output –

Category Name: .NET CLR Data

Category Name: .NET CLR Exceptions

Category Name: .NET CLR Interop

Category Name: .NET CLR Jit

…

Category Name: Active Server Pages

Category Name: APP_POOL_WAS

Category Name: ASP.NET

…

Category Name: Per Processor Network Interface Card Activity

Category Name: PhysicalDisk

Category Name: Print Queue

Category Name: Process

Category Name: Processor

…
…
…

The above code displays all available performance counter categories order by category name.

Performance Counters by Category

Below example demonstrates how we can get all the performance counters for given category. We can also get all the counters for all the categories if you don’t specify category name in below code but it will take a while to execute. So in below code I have retrieved performance counters only for "Memory" category.

//Get all performance categories

PerformanceCounterCategory[] perfCats = PerformanceCounterCategory.GetCategories();

//Get single category by category name.

PerformanceCounterCategory cat = perfCats.Where(c => c.CategoryName == "Memory").FirstOrDefault();

Console.WriteLine("Category Name: {0}", cat.CategoryName);

//Get all instances available for category

string[] instances = cat.GetInstanceNames();

if (instances.Length == 0)

{

    //This block will execute when category has no instance.

    //loop all the counters available withing category

    foreach (PerformanceCounter counter in cat.GetCounters())

        Console.WriteLine("     Counter Name: {0}", counter.CounterName);

}

else

{

    //This block will execute when category has one or more instances.

    foreach (string instance in instances)

    {

        Console.WriteLine("  Instance Name: {0}", instance);

        if (cat.InstanceExists(instance))

            //loop all the counters available withing category

            foreach (PerformanceCounter counter in cat.GetCounters(instance))

                Console.WriteLine("     Counter Name: {0}", counter.CounterName);

    }

}

Output –

Category Name: Memory

     Counter Name: Page Faults/sec

     Counter Name: Available Bytes

     Counter Name: Committed Bytes

     Counter Name: Commit Limit

     Counter Name: Write Copies/sec

     Counter Name: Transition Faults/sec

     Counter Name: Cache Faults/sec

     Counter Name: Demand Zero Faults/sec

     Counter Name: Pages/sec

     Counter Name: Pages Input/sec

     Counter Name: Page Reads/sec

     Counter Name: Pages Output/sec

     Counter Name: Pool Paged Bytes

     Counter Name: Pool Nonpaged Bytes

     Counter Name: Page Writes/sec

     Counter Name: Pool Paged Allocs

     Counter Name: Pool Nonpaged Allocs

     Counter Name: Free System Page Table Entries

     Counter Name: Cache Bytes

… … …

The above code returns name of the counters available in 'Memory' category. Memory category doesn’t contain any instances so it will list all the performance counters without displaying instance name. We can also execute same code for category which has instances. So let’s execute the same code with “Processor” category.

PerformanceCounterCategory cat = perfCats.Where(c => c.CategoryName == "Processor").FirstOrDefault();

Output –

Category Name: Processor

  Instance Name: _Total

     Counter Name: % Processor Time

     Counter Name: % User Time

     Counter Name: % Privileged Time

     Counter Name: Interrupts/sec

     Counter Name: % DPC Time

     Counter Name: % Interrupt Time

     Counter Name: DPCs Queued/sec

     Counter Name: DPC Rate

     Counter Name: % Idle Time

     Counter Name: % C1 Time

     Counter Name: % C2 Time

     Counter Name: % C3 Time

     Counter Name: C1 Transitions/sec

     Counter Name: C2 Transitions/sec

     Counter Name: C3 Transitions/sec

  Instance Name: 0

     Counter Name: % Processor Time

     Counter Name: % User Time

     Counter Name: % Privileged Time

     … … …

  Instance Name: 1

     Counter Name: % Processor Time

     Counter Name: % User Time

     Counter Name: % Privileged Time

     … … …

As per change in category of above code, now output displays all the performance counters available in 'Processor' category. Processor category has three instances so it will list all the performance counters with instance name.

Reading Performance Counter Value

PerformanceCounter class used to retrieve value of performance counter. This class is also available in System.Diagnostics namespace. We need to pass CategoryName, CounterName and InstanceName (Optional) to PerformanceCounter class constructor or we need to set those properties to performance counter instance explicitly. Performance counter instance has NextValue method which can be used to retrieve the value of give performance counter. 

Let’s have a look on below code.

DispatcherTimer timer = new DispatcherTimer();

timer.Interval = new TimeSpan(0,0,1);

timer.Tick += new EventHandler(timer_Tick);

timer.Start();

void timer_Tick(object sender, EventArgs e)

{

    using (PerformanceCounter perfCounter = new PerformanceCounter("Memory",

             "Available MBytes"))

    {

        float value = perfCounter.NextValue();

        Console.WriteLine("Total Memory Available: {0} MB.", value);

    }

}

Output –

Total Memory Available: 236 MB.

Total Memory Available: 239 MB.

Total Memory Available: 236 MB.

Total Memory Available: 231 MB.

Total Memory Available: 218 MB.

Total Memory Available: 221 MB.

Total Memory Available: 237 MB.

Total Memory Available: 237 MB.

Adding custom categories and counters

The new counters and categories can be added and measured through C# code. Dotnet provides PerformanceCounterCategory class to create new category and CounterCreationData class to create new performance counter.  You can create multiple counters under single category. The create method of PerformanceCounterCategory accepts collection of CounterCreationData. Let’s have a look on below code.

string category = "MyCategory";

string counter1 = "Counter1";

//Check whether category is exist or not

if (!PerformanceCounterCategory.Exists(category))

{

    //creates collection of CounterCreationData

    CounterCreationDataCollection counterDataCollection =

           new CounterCreationDataCollection();

    //added new CounterCreationData to counterDataCollection

    counterDataCollection.Add(new CounterCreationData(counter1,

          "My custom counter", PerformanceCounterType.NumberOfItems32));

    //Creates new category based on information and creates

      counters available in counter data collection

    PerformanceCounterCategory.Create(category, "My Category", PerformanceCounterCategoryType.SingleInstance, counterDataCollection);

}

Output –

As per above image from performance monitor tool, MyCategory is created and Counter1 is added to it. You can delete category by calling PerformanceCounterCategory.Delete method. To create and delete performance counters and categories you need administrative privileges. 

See Also –

How to create stopwatch application in WPF?
How to read/write windows event logs?

How to get call stack of running application?