CODEWITHSUNDEEP
c#
Jimmy Howe
Jimmy Howe

Reputation: 185

Using PerformanceCounter.GetNext()

Can anybody tell me why this doesn't work. My guess is its something to do with instantiation or the global values.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Diagnostics;
using System.Threading;
using System.Speech.Synthesis;

namespace UtilApp
{
    class Perf
    {
        #region Performance Counters
        // CPU utilization
        PerformanceCounter CPU_Perf = new PerformanceCounter("Processor Information", "% Processor Time", "_Total");
        // Memory left
        PerformanceCounter MEM_Perf = new PerformanceCounter("Memory", "Available MBytes");
        // System Up time
        PerformanceCounter SYS_Perf = new PerformanceCounter("System", "System Up Time");
        #endregion

        public int getUsedCPU()
        {
            Console.WriteLine("Requested CPU Usage...");
            int v = (int) CPU_Perf.NextValue();
            Console.WriteLine("Value: {0}", v);
            return v;
        }

        public int getFreeMEM()
        {
            return (int) MEM_Perf.NextValue();
        }

        public int getUpTime()
        {
            return (int) SYS_Perf.NextValue();
        }
    }
}

Basically, getUsedCPU() always returns 0, when I know that is not true. I copied this over from a console application I built using a tutorial online.

I'm accessing it from a form to show CPU usage like so...

Perf p = new Perf;
label1.text = p.getUsedCPU().toString();

NOTE: the console.writeline are for debugging, but still get 0 without them.

Upvotes: 0

Views: 274

Answers (2)

Eduardo Vélez
Eduardo Vélez

Reputation: 193

Add a class constructor, then create the instance of objects:

PerformanceCounter CPU_Perf;
PerformanceCounter MEM_Perf;
PerformanceCounter SYS_Perf;

public Perf()
{
        PerformanceCounter CPU_Perf = new PerformanceCounter("Processor Information", "% Processor Time", "_Total");
        PerformanceCounter MEM_Perf = new PerformanceCounter("Memory", "Available MBytes");
        PerformanceCounter SYS_Perf = new PerformanceCounter("System", "System Up Time");
}

Upvotes: 0

Christos
Christos

Reputation: 53958

From the MSDN

If the calculated value of a counter depends on two counter reads, the first read operation returns 0.0.

So, if you call once more the method, then you will get that you are looking for.

Furthermore, from here:

To obtain performance data for counters that required an initial or previous value for performing the necessary calculation, call the NextValue method twice and use the information returned as your application requires.

Why this happens?

This happens, as Jon mentioned in his comment, because the OP is creating a new instance of Perf each time.

Upvotes: 4

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