Why System.Runtime throwing NotSupportedException in EventSources

[michalwawa]

Hello

I'm new to opentelemetry and I have a question about fragment of code in EventCountersInstrumentationOptions:

public void AddEventSources(params string[] names)
    {
        if (names.Contains("System.Runtime"))
        {
            throw new NotSupportedException("Use the `OpenTelemetry.Instrumentation.Runtime` or `OpenTelemetry.Instrumentation.Process` instrumentations.");
        }

        this.eventSourceNames.UnionWith(names);
    }

What is a reason to throw this exception while using EventSources ?
My problem is that i cant get all needed data from AddProcessInstrumentation. I need for example cpu-usage from System.Runtime eventcounter, but this Instrumentation extensions is giving me: process_cpu_utilization_1 or process_cpu_time_s.

Or maybe im wrong and process_cpu_utilization is what im looking for ? But this value should be multiple by 100 to get %?

Another question ia about Unit type 1 ? What kind of unit it is ?