Calculate total CPU usage

Question

What is best algorithm for calculating total CPU usage at a particular time during execution of a process.

I am working windows platform in C++.

Answer 1

// Declare
PerformanceCounter cpuCounter = null;

// initialize somewhere in the constructor..
cpuCounter = new PerformanceCounter();
cpuCounter.CategoryName = "Processor";
cpuCounter.CounterName = "% Processor Time";
cpuCounter.InstanceName = "_Total";

Then to get the CPU usage in % just call
cpuCounter.NextValue()

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