For this demonstration, we'll use a 64-bit environment with a .NET 4.0 application built with Visual Studio 2019. Ensure you have the correct version of Windbg (64-bit) installed.

Creating a Test Scenario

We'll simulate high CPU usage with a sample application containing an ententional infinite loop:

using System.Threading.Tasks;

class CpuSpikeDemo 
{
    static void Main() 
    {
        Parallel.For(0, int.MaxValue, (i) => 
        {
            while (true) { /* Infinite loop */ }
        });
    }
}

Capturing Diagnostic Data

Use Procdump to capture memory dumps when CPU exceeds 70% for 5 seconds:

procdump CpuSpikeDemo -s 5 -n 2 -c 70

Analyzing the Dump File

Open the dump file in Windbg and load the necessary .NET debugging extensions:

.load C:\Windows\Microsoft.NET\Framework64\v4.0.30319\sos.dll
.load C:\Windows\Microsoft.NET\Framework64\v4.0.30319\clr.dll

Identify CPU-intensive threads:

!runaway

Examine busiest thread's stack trace:

~9s
!clrstack

The stack trace will point to the problematic code location (in our case, line 14 containing the infinite loop).