Why the cpu performance counter kept reporting 0% cpu usage?

Question

PerformanceCounter cpuload = new PerformanceCounter(); cpuload.CategoryName = "Processor"; cpuload.CounterName = "% Processor Time"; cpuload.InstanceName = "_Total"; Console.WriteLine(cpuload.NextValue() + "%"); 

The output is always 0%, while the cpuload.RawValue is like 736861484375 or so, what happened at NextValue()?

Answer 1

The first iteration of he counter will always be 0, because it has nothing to compare to the last value. Try this:

var cpuload = new PerformanceCounter("Processor", "% Processor Time", "_Total"); Console.WriteLine(cpuload.NextValue() + "%"); Console.WriteLine(cpuload.NextValue() + "%"); Console.WriteLine(cpuload.NextValue() + "%"); Console.WriteLine(cpuload.NextValue() + "%"); Console.WriteLine(cpuload.NextValue() + "%"); 

Then you should see some data coming out. It's made to be seen in a constant graph or updated scenario...that's why you don't come across this problem often.

Here's the MSDN reference:

The method nextValue() always returns a 0 value on the first call. So you have to call this method a second time.

Answer 2

First retrieve first value (would be 0)

NextValue(); 

Then wait for 1000 milisec

Thread.Sleep(1000); 

Then retrieve second value which is the true cpu usage.

NextValue(); 

The code should look like this:

float perfCounterValue = perfCounter.NextValue();  //Thread has to sleep for at least 1 sec for accurate value. System.Threading.Thread.Sleep(1000);  perfCounterValue = perfCounter.NextValue();  Console.WriteLine("Value: {0}", perfCounterValue);