model/profile: add symbolization information

[florianl]

Changes

Add Profiling specific attributes that describe the symbolization level of a Mapping.

FYI: @open-telemetry/profiling-approvers

Merge requirement checklist

• CONTRIBUTING.md guidelines followed.
• Change log entry added, according to the guidelines in When to add a changelog entry.
  • If your PR does not need a change log, start the PR title with [chore]
• Links to the prototypes or existing instrumentations (when adding or changing conventions)

[aalexand]

I think we agreed here to add these as pprof.* boolean attributes equivalent to the current pprof's proto attributes since use cases other than pprof's were unclear to us and for pprof keeping the current semantics is the easiest for the migration.

[florianl]

@aalexand thanks for reminding me about the pprof group. I did forget about this 🙈 updated the PR accordingly

But I don't recall from the recoding, that we agreed on a 1:1 mapping from the google/pprof has_* fields. To me, the suggestions you made in open-telemetry/opentelemetry-proto#595, made sense as they add information about the quality of the symbol information. Using the 1:1 mapping from the google/pprof has_* fields does not allow the backend to make a sound decision on the quality of the received information.

[aalexand]

Given open-telemetry/opentelemetry-proto#690 and the discussion in the Slack, what do you think about making adding the is_folded attribute a part of this PR as well? I think it might be easier and more convenient to review adding all of these at once. This will help ensure consistency in naming and typing etc.

[florianl]

Cherry-picked and so added the is_folded change here as well.

[thompson-tomo]

Hmm, I am not sure about this proposal here. Is it the idea that the collector would transform a profile message to become a span hence wanting attribute to represent the low level message properties?

Keep in mind the idea of adding attributes to the registry is so that they can be the key & sometimes value used in the attributes property of the message ie https://github.com/open-telemetry/opentelemetry-proto/blob/8654ab7a5a43ca25fe8046e59dcd6935c3f76de0/opentelemetry/proto/profiles/v1development/profiles.proto#L114

If you are wanting to define a profile message hence using attributes to indicate if that message should have functions for instance I would recommend you raise an issue weaver listing what are the properties of a profile.

It might help to define how these attributes would be used,

[aalexand]

@jhalliday @christos68k to take a look also

[felixge]

LGTM, thanks @florianl 🙇