Question

been searching around for this for a while, and hoping someone here can answer my question. So I am trying to find the best way to get the average CPU usage of 2 or 4 cores. Currently I am using a Performance Counter which so far as I can tell, only returns the usage of a single core. Ideally I would like it to match or at least resemble the Usage bar in Task Manager, and I have looked into WMI queries but was hoping to get some clarification on the best approach. I am currently using an i7, which has hyperthreading, i.e has “8” cores. Not sure if this makes much difference, but though it might.
Thanks for any pointers

Answer 1

Using Win32_PerfFormattedData_Counters_ProcessorInformation, you can use the field PercentProcessorTime which will give instances of every core/thread on your system with its respective usage.

I just tried this on mine, and I got 8 Management Objects for my 8 threads.

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_Counters_ProcessorInformation"); 

                foreach (ManagementObject queryObj in searcher.Get())
                {
                    Console.WriteLine("-----------------------------------");
                    Console.WriteLine("Win32_PerfFormattedData_Counters_ProcessorInformation instance");
                    Console.WriteLine("-----------------------------------");
                    Console.WriteLine("PercentProcessorTime: {0}", queryObj["PercentProcessorTime"]);
                }
            }
            catch (ManagementException e)
            {
                MessageBox.Show("An error occurred while querying for WMI data: " + e.Message);
            }
        }
    }
}

Update:

That was a slight lie, I got 10 instances.
Their names were:

1. _Total
2. 0,_Total
3. 0,7
4. 0,6
5. 0,5

etc.
You should filter out what you need with a where clause:

SELECT PercentProcessorTime FROM Win32_PerfFormattedData_Counters_ProcessorInformation WHERE NOT Name='_Total' AND NOT Name='0,_Total'