[Instrumentation.Process] Exposed required metric process.cpu.count for computing CPU utilization in the backend.

[Yun-Ting]

Based on spec discussion: open-telemetry/opentelemetry-specification#2392 (comment)
Related to: #972.

Changes

Exposed required metric process.processors for computing CPU utilization in the backend.

For significant contributions please make sure you have completed the following items:

• Appropriate CHANGELOG.md updated for non-trivial changes
• Design discussion issue #
• Changes in public API reviewed

[Kielek]

Can we open discussion on spec side once more time? The minimal effort - decide the name in the spec side.
I would like to avoid some custom metric in the repository created only for one language and then potential subject to change.

[CodeBlanch]

process.processors is kind of tongue twister 🤣 process.cpu.count is much nicer IMO. Probably process.threads -> process.thread.count would also be good.

[Yun-Ting]

Can we open discussion on spec side once more time? The minimal effort - decide the name in the spec side. I would like to avoid some custom metric in the repository created only for one language and then potential subject to change.

I've created an issue in the spec side!
open-telemetry/semantic-conventions#651

[reyang]

LGTM, the spec dependency is not a blocker IMHO given the component and the spec are both preview/experimental.

[codecov]

Codecov Report

Merging #981 (5649f33) into main (4d7f93e) will increase coverage by 0.02%.
The diff coverage is 100.00%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     open-telemetry/opentelemetry-specification#981      +/-   ##
==========================================
+ Coverage   68.11%   68.13%   +0.02%     
==========================================
  Files         184      184              
  Lines        7013     7021       +8     
==========================================
+ Hits         4777     4784       +7     
- Misses       2236     2237       +1     

Impacted Files	Coverage Δ
...elemetry.Instrumentation.Process/ProcessMetrics.cs	100.00% <100.00%> (ø)
...try.Extensions/Trace/AutoFlushActivityProcessor.cs	77.77% <0.00%> (-3.71%)	⬇️