C# - Performance Counter lower than Taskmanager %

Question

I try to make a class which will fetch different usages from the pc, the problem that I have atm is that the CPU usage is under what Task Manager displays (with about 10%).

Can you please have a look and point me in the right direction ? Please no answers without explanation, I want to learn !

Here is what I have atm :

using System.Diagnostics;
using System.Net.NetworkInformation;

namespace ConsoleApplication2
{
    class UsageFetcher
    {
        ulong totalRAM;

        PerformanceCounter cpuUsage;
        PerformanceCounter ramUsage;
        PerformanceCounter diskUsage;

        NetworkInterface[] networkUsage;

        public UsageFetcher()
        {
            // Fetching total amount of RAM to be able to determine used persantage
            //totalRAM = new Microsoft.VisualBasic.Devices.ComputerInfo().TotalPhysicalMemory;
            totalRAM = this.getTotalRam();

             // Creating a new Perfromance Counter who will be used to get the CPU Usage
            cpuUsage = new PerformanceCounter();

            // Setting it up to fetch CPU Usage 
            cpuUsage.CategoryName = "Processor";
            cpuUsage.CounterName = "% Processor Time";
            cpuUsage.InstanceName = "_Total";

            /*
             * Fetching the first two reads
             * First read is always 0 so we must elimiate it
             */
            cpuUsage.NextValue();
            cpuUsage.NextValue();

            // Creating a new Performance Counter who will be used to get the Memory Usage
            ramUsage = new PerformanceCounter();

            // Setting it up to fetch Memory Usage
            ramUsage.CategoryName = "Memory";
            ramUsage.CounterName = "Available Bytes";

            // Fetching the first two reads !! Same reason as above !!
            ramUsage.NextValue();
            ramUsage.NextValue();
        }

        public string getCPUUsage()
        {
            /* 
             * Requesting the usage of the CPU
             * It is returned as a float thus I need to call ToString()
             */
            return cpuUsage.NextValue().ToString();
        }

        public string getMemUsage()
        {
            // Requesting memory usage and calculate how much is free
            return (100 -ramUsage.NextValue() / totalRAM * 100).ToString();
        }

        public ulong getTotalRam()
        {
            return new Microsoft.VisualBasic.Devices.ComputerInfo().TotalPhysicalMemory ;
        }
    }
}

So you are saying that actually is vice versa ? Task is wrong ? Can you please explain. Thanks ! — Petru Daniel Tudosiu, Aug 06 '15 at 13:50
No, Im saying that you cant really prove either is right or wrong. Task manager often shows different results to other products that do the same thing, task manager shows a snapshot as at an exact ms in time, if you dont grab the same ms, your results can be different. Its hard to compare them for sure, but also, no one says task manager isnt lying — BugFinder, Aug 06 '15 at 13:51
But the information fetched by the counter is almost constantly under the task manager with 10% — Petru Daniel Tudosiu, Aug 06 '15 at 13:52
@BugFinder you are right ... task manager is showing more than the actual cpu usage. I calculated (tried to) the cpu usage by adding up the percentages and my total is closer to my program output than to task manager by a lot. — Petru Daniel Tudosiu, Aug 06 '15 at 14:25
Wierd ... I tried another program for monitoring CPU usage and it shows approximately the same as Task Manager... — Petru Daniel Tudosiu, Aug 06 '15 at 15:01

score 0 · Answer 1 · edited May 23 '17 at 12:06

0

According to this SO post here: Why the cpu performance counter kept reporting 0% cpu usage?

You need to sleep for at least a second for the NextValue() method to return a decent result.

Try adding a call to Sleep between your calls to NextValue and see what you get.

edited May 23 '17 at 12:06

Community

1
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answered Aug 06 '15 at 13:58

Doug Dawson

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C# - Performance Counter lower than Taskmanager %

1 Answers1