Average CPU usage (%) over a few seconds

DynVec 

Hi.

While in theory this can be done via script, in practice, it's not going to work well. PowerShell is not the best choice here - at least, not for performing the actual monitoring. Instead, you should be using the Windows performance counter framework.

The reason for this is very simple.

When run, the PowerShell script runs in something called "user mode" (the other mode being "kernel mode") which comes with the default behaviour of running at "normal" priority.

When Windows starts struggling with high CPU utilisation (be that on one core or all - there's still plenty of single-threading applications out there), the first processes to become "unresponsive" are user-mode processes, meaning your monitoring script itself will be heavily impacted.

Conversely, the key elements of the Windows performance counter framework are run in kernel mode, meaning they are implicitly run at the highest process priorities and therefore more responsive when the system is under serious CPU load.

The visual tool provided in Windows for interfacing with the performance counters is called "Performance Monitor" - or perfmon for short.

Perfmon can generate charts, logs and alerts - and it may be alerts that are most interesting to you as they can in turn trigger various actions, including starting performance counter logging (quite powerful for finding the root cause behind the CPU spike - such as transient low memory and therefore excessive paging), sending e-mails and running scripts.

Here's a simple view of Perfmon and the alerts dialog:

And here's some useful links relating to Perfmon - you can ignore the SQL context as the concepts and steps relate to all applications, and Perfmon is a Windows tool, not an SQL Server-specific tool:

• Create Charts, Alerts, Logs, and Reports in System Monitor - SQL Server | Microsoft Learn
• Monitor Resource Usage (Performance Monitor) - SQL Server | Microsoft Learn
• Monitor performance of remote computers - Windows Server | Microsoft Learn
• Create performance counter alert and send email - Windows Server | Microsoft Learn

Once a data collector has been defined, you can use the "Save as template" menu option to export the full definition as an XML file, which can then be imported to as many other computers as you like.

Lastly, the performance counters framework is available in all versions of Windows NT and has been since the 90's (the Perfmon tool hasn't changed much since Vista/2008), so the same approach not only works across Windows 10 and 11 but likely all future versions of Windows, too.

Anyhow, it's your decision as to whether you continue with the PowerShell script approach, but as it's negatively impacted by the very condition you're looking to identify, I wouldn't recommend it.

Cheers,

Lain