[REQUEST] - Add documentation for using performance counters

[VihasMakwana]

Description

We have recently introduced an alternative way to collect cpu and core metrics. This feature is effective for windows and it should be used when running beats on machines with more than 64 cores.

This is a bug fix for elastic/beats#40926.
This feature is effective from metricbeat version 8.17.1 and 8.16.3 onwards.

How to use this feature?

You can enable it like following:

metricbeat.modules:

#-------------------------------- System Module --------------------------------
- module: system
  period: 30s
  use_performance_counters: true
  metricsets:
    - cpu
  enabled: true
  cpu.metrics:
    - normalized_percentages
    - percentages

FAQ:
Q. Are there any impact of enabling this feature on non-windows OSes?

• No. This feature is only effective for windows. For other OSes, it is a no-op

Q. What if we enable this feature on machines with less than 64 cores?

• If you enable this on machine with fewer than 64 cores on Windows, it would again in the same way as before.

Resources

Relevant PR: elastic/beats#41965
Issue: elastic/beats#40926

Collaboration

The documentation team will investigate the issue and create the initial content.

Point of contact.

Main contact: @VihasMakwana

Stakeholders: @nimarezainia @flexitrev @jlind23 @cmacknz

[cmacknz]

This should be documented for Metricbeat in Beats.

For agent, this option should just be exposed in the system integration https://github.com/elastic/integrations/tree/main/packages/system and I don't see it there. @VihasMakwana can follow up and add support for this in the system integration, otherwise this is unusable from Elastic Agent.

[kilfoyle]

Thanks for the clarification @cmacknz. @VihasMakwana I see this is already covered in the Beats docs via elastic/beats#41965 (see System cpu metricset).

So, since this is unusable from Elastic Agent, I think this issue can be closed, but let me know if that's not right. Also, please note that there's a documentation freeze starting at end of day today, so any docs changes we need will have to wait until after Feb 20.