profcheck: Mixed signals

[javierhonduco]

Hi all! First of all congrats and thank you for reaching Alpha! 🎉 . I started to integrate the OTel format in some of the tools I am working on that used pprof/custom formats. I really love that this validator exists! I just ran it on the first otel profile I produced and got a slightly confusing output:

$ nix run .#profcheck profile.otel.pb |& grep "profile.otel.pb:"
profile.otel.pb: conformance checks failed: resource_profiles[0]: scope_profiles[0]: profile[0]: sample[0]: attribute_indices: [3].key_strindex: duplicate key "pid", previously seen at [0].key_strindex
profile.otel.pb: conformance checks passed

Is this expected? I have checked the code and perhaps this line should only run if there are no issues?

sig-profiling/profcheck/cmd/profcheck/main.go

Line 58 in 80a3acd

fmt.Printf("%s: conformance checks passed\n", inputPath)

Thank you!

[javierhonduco]

Sharing the (probably very broken profile!) here in case it's useful profile.otel.pb.zip

[florianl]

hi @javierhonduco
I did have a brief look into your provided data:

 protoc --proto_path=/home/user/src/github.com/open-telemetry/opentelemetry-proto \
  --decode=opentelemetry.proto.profiles.v1development.ProfilesData \
  opentelemetry/proto/profiles/v1development/profiles.proto < profile.otel.pb

Looking at sample[0] it holds the following attribute indices: 3,4,5,6,7,8,9
Looking up these attributes in the attribute_table, we see, that indices 3 and 6 have the same key pid (or 29 as key_strindex). But both attributes with the same key do hold different values 9698 (for attribute index 3) and 9661 (for attribute index 6). A single sample with only a single value (52631578 in this case) can not have two different pids.

I also noticed that attribute_table, also holds duplicate entries - e.g. attribute index 14 with key_strindex of 29 and attribute index 17 with key_strindex of 29 both hold the value 228.

But there is also a logical error in profcheck that should be fixed with #98.

[javierhonduco]

Thank you for the fix!