How to get the CPU Usage in C#?

Question

I want to get the overall total CPU usage for an application in C#. I've found many ways to dig into the properties of processes, but I only want the CPU usage of the processes, and the total CPU like you get in the TaskManager.

How do I do that?

Deathtrap

#4680462 – Wangle

How on earth is this off topic? Ridiculous. – Overfly

Answer 1

You can use the PerformanceCounter class from System.Diagnostics.

Initialize like this:

PerformanceCounter cpuCounter;
PerformanceCounter ramCounter;

cpuCounter = new PerformanceCounter("Processor", "% Processor Time", "_Total");
ramCounter = new PerformanceCounter("Memory", "Available MBytes");

Consume like this:

public string getCurrentCpuUsage(){
            return cpuCounter.NextValue()+"%";
}

public string getAvailableRAM(){
            return ramCounter.NextValue()+"MB";
} 

Hygroscope

Nice - but the original source appears to be from here: zamov.online.fr/EXHTML/CSharp/CSharp_927308.html – Antibes

From what i discovered i had to use cpuCounter.NextValue() twice and between them i had to Sleep(500) – Sextillion

Matt is right. Even including the bugs, like forgetting the "return" keyword. – Capo

yeah, it looks like a copy from that link, so a link for reference of the original would have been nice style. On the otherhand, its also nice of CMS to provide the answer here so lazy developers dont have to search all over Google to find the same answer. :o) – Wiggle

You will need to call .NextValue twice, with a System.Threading.Thread.Sleep call in-between (1000ms should suffice). See blogs.msdn.com/b/bclteam/archive/2006/06/02/618156.aspx for more information on why this is required, but the high level summary is that you need to two samples in order to calculate the value, and you need to give the OS a time to get both of these. – Entree

Wont the '_Total' instance the total CPU consumed as opposed to CPU consumed by a particular application? – Whist

@Sextillion Ok, this worked, but can you please explain to me why it worked and why the sleep was needed? – Clinkscales

This isn't super accurate on windows 10 btw. It generally reads 4-6% lower than task manager. Result may vary – Parian

I'm not able to get the same value as task manager even adding sleep between nextvalue calls. – Bield

From what we've learned, the Windows 10 task manager is not accurate 90% of the time anyway.... – Deannadeanne

Be aware that retrieving the CPU load in this manner takes fairly long and also creates additional CPU load. See #25372573 and #32106607 – Langley

@Entree The current URL is: learn.microsoft.com/en-us/archive/blogs/bclteam/… – Engle

Answer 2

A little more than was requsted but I use the extra timer code to track and alert if CPU usage is 90% or higher for a sustained period of 1 minute or longer.

public class Form1
{

    int totalHits = 0;

    public object getCPUCounter()
    {

        PerformanceCounter cpuCounter = new PerformanceCounter();
        cpuCounter.CategoryName = "Processor";
        cpuCounter.CounterName = "% Processor Time";
        cpuCounter.InstanceName = "_Total";

                     // will always start at 0
        dynamic firstValue = cpuCounter.NextValue();
        System.Threading.Thread.Sleep(1000);
                    // now matches task manager reading
        dynamic secondValue = cpuCounter.NextValue();

        return secondValue;

    }


    private void Timer1_Tick(Object sender, EventArgs e)
    {
        int cpuPercent = (int)getCPUCounter();
        if (cpuPercent >= 90)
        {
            totalHits = totalHits + 1;
            if (totalHits == 60)
            {
                Interaction.MsgBox("ALERT 90% usage for 1 minute");
                totalHits = 0;
            }                        
        }
        else
        {
            totalHits = 0;
        }
        Label1.Text = cpuPercent + " % CPU";
        //Label2.Text = getRAMCounter() + " RAM Free";
        Label3.Text = totalHits + " seconds over 20% usage";
    }
}

Semitic

Where is the getRAMCounter()? – Phototonus

cpuCounter.NextValue returns a float. So why assign it to a dynamic? Then why return that dynamic as an object? Then why try to assign an object to an int in the line int cpuPercent = getCPUCounter()? (That code will not compile.) – Hl

I get "The type or namespace name PerformanceCounter could not be found", and thread can't be found in System.Threading namespace either. – Caldera

Everyone is guaranteed to get "I get "The type or namespace name PerformanceCounter could not be found" error. Solution does not work. – Intervalometer

Answer 3

After spending some time reading over a couple different threads that seemed pretty complicated I came up with this. I needed it for an 8 core machine where I wanted to monitor SQL server. For the code below then I passed in "sqlservr" as appName.

private static void RunTest(string appName)
{
    bool done = false;
    PerformanceCounter total_cpu = new PerformanceCounter("Process", "% Processor Time", "_Total");
    PerformanceCounter process_cpu = new PerformanceCounter("Process", "% Processor Time", appName);
    while (!done)
    {
        float t = total_cpu.NextValue();
        float p = process_cpu.NextValue();
        Console.WriteLine(String.Format("_Total = {0}  App = {1} {2}%\n", t, p, p / t * 100));
        System.Threading.Thread.Sleep(1000);
    }
}

It seems to correctly measure the % of CPU being used by SQL on my 8 core server.

Castellated

total_cpu should be PerformanceCounter("Processor"), not PerformanceCounter("Process").. otherwise you just get 100% * number of cores. – Variation

Where do you set done to true? Unless I have overlooked something, this appears to be an endless loop: while(!done){...} – Handley

@Handley It is indeed an endless loop – Carminacarminative

Old topic but it's just a comment | Why are you not using while(true) ? – Polder

I get "The type or namespace name PerformanceCounter could not be found – Intervalometer

Answer 4

It's OK, I got it! Thanks for your help!

Here is the code to do it:

private void button1_Click(object sender, EventArgs e)
{
    selectedServer = "JS000943";
    listBox1.Items.Add(GetProcessorIdleTime(selectedServer).ToString());
}

private static int GetProcessorIdleTime(string selectedServer)
{
    try
    {
        var searcher = new
           ManagementObjectSearcher
             (@"\\"+ selectedServer +@"\root\CIMV2",
              "SELECT * FROM Win32_PerfFormattedData_PerfOS_Processor WHERE Name=\"_Total\"");

        ManagementObjectCollection collection = searcher.Get();
        ManagementObject queryObj = collection.Cast<ManagementObject>().First();

        return Convert.ToInt32(queryObj["PercentIdleTime"]);
    }
    catch (ManagementException e)
    {
        MessageBox.Show("An error occurred while querying for WMI data: " + e.Message);
    }
    return -1;
}

Client

Add getting server name instead of variable selectedServer was better. like this.string computername = Environment.GetEnvironmentVariable("computername"); – Rehm

Answer 5

You can use WMI to get CPU percentage information. You can even log into a remote computer if you have the correct permissions. Look at http://www.csharphelp.com/archives2/archive334.html to get an idea of what you can accomplish.

Also helpful might be the MSDN reference for the Win32_Process namespace.

See also a CodeProject example How To: (Almost) Everything In WMI via C#.

Helotry

Answer 6

CMS has it right, but also if you use the server explorer in visual studio and play around with the performance counter tab then you can figure out how to get lots of useful metrics.

Facet

Answer 7

For those who still could not get the total CPU usage figure which matches Task Manager, you should use this statement:

var pCounter = new PerformanceCounter("Processor Information", "% Processor Utility", "_Total");
var cPUUsgae = pCpu.NextValue();

Hamate

For modern and multi-core processors, this is the correct answer. – Aceous

Answer 8

This class automatically polls the counter every 1 seconds and is also thread safe:

public class ProcessorUsage
{
    const float sampleFrequencyMillis = 1000;

    protected object syncLock = new object();
    protected PerformanceCounter counter;
    protected float lastSample;
    protected DateTime lastSampleTime;

    /// <summary>
    /// 
    /// </summary>
    public ProcessorUsage()
    {
        this.counter = new PerformanceCounter("Processor", "% Processor Time", "_Total", true);
    }

    /// <summary>
    /// 
    /// </summary>
    /// <returns></returns>
    public float GetCurrentValue()
    {
        if ((DateTime.UtcNow - lastSampleTime).TotalMilliseconds > sampleFrequencyMillis)
        {
            lock (syncLock)
            {
                if ((DateTime.UtcNow - lastSampleTime).TotalMilliseconds > sampleFrequencyMillis)
                {
                    lastSample = counter.NextValue();
                    lastSampleTime = DateTime.UtcNow;
                }
            }
        }

        return lastSample;
    }
}

Behre

System.DateTime is actually an 8 byte value type which means that assignments to a DateTime variable are not atomic. This code is not thread safe on 32 bit platforms. – Hawk

Answer 9

This seems to work for me, an example for waiting until the processor reaches a certain percentage

var cpuCounter = new PerformanceCounter("Processor", "% Processor Time", "_Total");
int usage = (int) cpuCounter.NextValue();
while (usage == 0 || usage > 80)
{
     Thread.Sleep(250);
     usage = (int)cpuCounter.NextValue();
}

Civics

why are you sleeping when the usage is 0? – Laconic

I get "The type or namespace name PerformanceCounter could not be found – Intervalometer

Answer 10

I did not like having to add in the 1 second stall to all of the PerformanceCounter solutions. Instead I chose to use a WMI solution. The reason the 1 second wait/stall exists is to allow the reading to be accurate when using a PerformanceCounter. However if you calling this method often and refreshing this information, I'd advise not to constantly have to incur that delay... even if thinking of doing an async process to get it.

I started with the snippet from here Returning CPU usage in WMI using C# and got here:

//Get CPU usage values using a WMI query
ManagementObjectSearcher searcher = new ManagementObjectSearcher("select * from Win32_PerfFormattedData_PerfOS_Processor");
var cpuTimes = searcher.Get()
                .Cast<managementobject>()
                .Select(mo => new {
                    Name = mo["Name"],
                    Usage = mo["PercentProcessorTime"]
                }).ToList();

//The '_Total' value represents the average usage across all cores,
//and is the best representation of overall CPU usage
var query = cpuTimes.Where(x => x.Name.ToString() == "_Total").Select(x => x.Usage);
var cpuUsage = query.SingleOrDefault();

If you want to verify the cpuUsage, add up each core's value in the cpuTimes List and then divide by the total number of cores to get the "_Total" value.

I have added a full explanation of the solution on my blog post below:

Get CPU Usage Across All Cores In C# Using WMI

Dualistic

Please include the answer here instead of linking to your blog. – Jorgensen

@Jorgensen - I did not just link to my blog; I gave an explanation 1st, and proceeded to provide a link for an in-depth answer beyond the post here. – Dualistic

the solution in your blog post is like 12 lines of code. Why not include that in your answer other than trying to get people to visit your blog? – Jorgensen

@Jorgensen - What's the problem with clicking on the link as it contains an in-depth explanation; that's the idea the 'why' portion elaboration? Also this is 7 years old, just saying. Tough to remember this exact post and me being a newb on SO back then. – Dualistic

the link could get broken, and it is much easier to scan answers when the core content is inline. Sorry for being harsh in my other reply, I'm not here to give you a hard time. :) – Jorgensen

I also suggest copying the code here, since its short. Other than that, theres' a bug on your page: ManagementObject in the Cast<ManagementObject> needs to be in capitals, types are case-sensitive, and your code with Cast<managementobject> does not compile. – Deannadeanne

Answer 11

public int GetCpuUsage()
{
    var cpuCounter = new PerformanceCounter("Processor", "% Processor Time", "_Total", Environment.MachineName);
    cpuCounter.NextValue();
    System.Threading.Thread.Sleep(1000); //This avoid that answer always 0
    return (int)cpuCounter.NextValue();
}

Original information in this link https://gavindraper.com/2011/03/01/retrieving-accurate-cpu-usage-in-c/

Dareen

I get "the type or namespace name PerformanceCounter could not be found" – Caldera

@Caldera - no one has mentioned it yet, but you need to include the System.Diagnostics.PerformanceCounter NuGet, and add "using System.Diagnostics;" to your code. – Kafka