Quickly determine CPU usage of all processes of a specific user on terminal server

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C#

Hello!

I'm looking for a quick way to find out the cumulative CPU usage of all processes of a specific user on a Terminal Server, as displayed by the TaskManager in the tab "Users".

The solutions via PerformanceCounters, which I have looked at so far, are all much too slow and require a relatively large amount of CPU time themselves.

My questions:
How do I determine all processes for a specific TS Session?
How do I determine the total CPU load of these processes?

If someone had something there, I would be very grateful.

Greetings

Ken

What I have tried:

I looked at various solutions, but they were all much too slow.