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

PerformanceCounter cpuload = new PerformanceCounter();
cpuload.CategoryName = "Processor";
cpuloa开发者_如何学JAVAd.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()?

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.

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);