Get the Cpu usage of each process from wmi

Question

I found many sources to get the cpu usage of each process. in general there are many ways to get the cpu usage of process .

1. percentprocessortime from win32_perfformatteddata_perfproc_process
2. performancecounter class in system.diagnostics
3. by manual calculation
4. Process class (by process.getcurrentprocess().totalprocessortime;) as said in here.

FirstWay:

For the remote process monitoring(my scenario is remote monitoring), the percentprocessortime always shows value 0 to 100+. this 100+ happens because of multiple processors in a system. it can be calculated by using percentprocessortime/ processorcount.

Question in firstway:

i can read the percentprocessortime in wmi explorer, it shows all the values are 0 or 100 only not other than this value. is this value is correct? or is it useful for monitoring the value?

Second Way:

for PerformanceCounter class monitoring, it can be done for local only. so i cannot use this. is it possible to use this for remote?

Third Way:

(biggest confusion happening here in terms of which formula to use.) this calculation is made either by a PerformanceCounter class or win32_process class from wmi. some says to calculate the performance counter by using the follwing

consider single CPU and

(processor\%processor time) = 10%

(processor\%user time) = 8%

(processor\% privilege time) = 2%

(process\% processor time\your application) = 80%

You application is using 80% of the (processor\% user time) which is (8*.8)=6.4% of the CPU.

for more refer here.

by calculating the usermodetime and kernelmodetime from win32_process by using the following formulae

DateTime firstSample, secondSample;
firstSample = DateTime.Now;
queryObj.Get();
//get cpu usage
ulong u_oldCPU = (ulong)queryObj.Properties["UserModeTime"].Value 
                +(ulong)queryObj.Properties["KernelModeTime"].Value;
//sleep to create interval
System.Threading.Thread.Sleep(1000);
//refresh object
secondSample = DateTime.Now;
queryObj.Get();
//get new usage
ulong u_newCPU = (ulong)queryObj.Properties["UserModeTime"].Value
               + (ulong)queryObj.Properties["KernelModeTime"].Value;
decimal msPassed = Convert.ToDecimal(
                             (secondSample - firstSample).TotalMilliseconds);

//formula to get CPU ussage
if (u_newCPU > u_oldCPU)
    PercentProcessorTime = (decimal)((u_newCPU - u_oldCPU) / 
                               (msPassed * 100 * Environment.ProcessorCount));

Console.WriteLine("Process name " + queryObj.Properties["name"].value);                       
Console.WriteLine("processor time " + PercentProcessorTime);

the above code results output in 85.999 and sometimes 135.89888. i was so confused which way can i calculate the cpu usage of process.

Note: Its a duplicate. I cannot come to the conclusion from the existing sources. and i was confused. so only i asked a question.

Odom

Answer 1

You can use WMI to query this. I think you are looking for Win32_PerfFormattedData_PerfProc_Process class.

using System;
using System.Management;
using System.Windows.Forms;

namespace WMISample
{
  public class MyWMIQuery
  {
    public static void Main()
    {
        try
        {
            ManagementObjectSearcher searcher = 
                new ManagementObjectSearcher("root\\CIMV2", 
                "SELECT * FROM Win32_PerfFormattedData_PerfProc_Process"); 

            foreach (ManagementObject queryObj in searcher.Get())
            {
                Console.WriteLine("-----------------------------------");
                Console.WriteLine("Name: {0}", queryObj["Name"]);
                Console.WriteLine("PercentProcessorTime: {0}", queryObj["PercentProcessorTime"]);
            }
        }
        catch (ManagementException e)
        {
            MessageBox.Show("An error occurred while querying for WMI data: " + e.Message);
        }
    }
  }
}

Output:-

Bookbinding

It seems to me the cpu usage ["PercentProcessorTime"] is just wrong. Only 3 processes with non 0 PercentProcessorTime _Total and idle at 100 and then next one seemingly random process with PercentProcessorTime around 5. – Doble

The value of queryObj["PercentProcessorTime"] must be divided by Environment.ProcessorCount. – Sharl