Implement unmarshal traces with jsoniter, make 35x faster than jsonpb(#4817)

[hanjm]

Description:

As the #4817 and the trace proto are stable, I implement unmarshal traces with jsoniter iterator parser, compare with jsonpb unmarshaller, jsoniter does not use reflect, more efficient, less GC pressure.
The benchmark results show 35x faster, 5x fewer allocs, 19x fewer alloc bytes.

$ go test -bench "Traces(J|P)"
goos: darwin
goarch: amd64
pkg: go.opentelemetry.io/collector/model/otlp
cpu: Intel(R) Core(TM) i7-9750H CPU @ 2.60GHz
BenchmarkTracesJSONUnmarshal-12            10000            107938 ns/op           83057 B/op       1228 allocs/op
BenchmarkTracesJSONiterUnmarshal-12       427092              2768 ns/op            4314 B/op        206 allocs/op

If it is acceptable. i think we can make JSON unmarshaller is configurable, jsonpb is default, jsoniter is optional.
I want to split the full function into a series of small PR:

1. Implement trace unmarshaller.
2. Implement logs unmarshaller.
3. Implement metrics unmarshaller.
4. Make theotlpreceiver support config jsoniter as optional unmarshaller.

Link to tracking Issue:
#4817
Testing: < Describe what testing was performed and which tests were added.>

1. unit test. construct a trace message, fill all the fields, use jsonpb marshal to json bytes, use jsoniter unmarshal to struct, test assert there are equal.

[codecov]

Codecov Report

Merging #4986 (1e46b4d) into main (041f398) will increase coverage by 0.22%.
The diff coverage is 98.98%.

@@            Coverage Diff             @@
##             main    #4986      +/-   ##
==========================================
+ Coverage   90.53%   90.76%   +0.22%     
==========================================
  Files         190      190              
  Lines       11111    11407     +296     
==========================================
+ Hits        10059    10353     +294     
- Misses        829      833       +4     
+ Partials      223      221       -2     

Impacted Files	Coverage Δ
pdata/ptrace/json.go	97.15% <98.98%> (+12.15%)	⬆️
pdata/internal/common.go	95.01% <0.00%> (+0.76%)	⬆️

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[bogdandrutu]

We try to discourage JSON usage because of performance impact in general anyway. What is the use case for using JSON instead of proto encoded?

[hanjm]

We try to discourage JSON usage because of performance impact in general anyway. What is the use case for using JSON instead of proto encoded?

Yes, I know JSON performance is lower than proto, but in some use case, JSON is more friendly to frontend(web/mobile) or Lua script runtime to report telemetry data. protobuf has extra generated code dependency.

I add a benchmark compare to jsoniter vs protobuf. jsoniter is only 2.x slower pb. a lot of improvements compare to jsonpb.

BenchmarkTracesJSONiterUnmarshal-12       493048              2324 ns/op            4001 B/op        185 allocs/op
BenchmarkTracesPBUnmarshal-12            1000000              1049 ns/op            2816 B/op         78 allocs/op

[hanjm]

related open-telemetry/opentelemetry-specification#1957

[hanjm]

We save 250 CPU cores in production after applying the optimized OTLP JSON jsoniter parser.

[bogdandrutu]

@hanjm sorry for the wait. I am waiting for the pdata split to finish first before making more changes in that package.

[bogdandrutu]

Please rebase.

[hanjm]

Rebase Done.
but the "contrib-tests" CI fail

# github.com/open-telemetry/opentelemetry-collector-contrib/pkg/translator/opencensus
pkg/translator/opencensus/metrics_to_oc.go:369:3: invalid case pmetric.MetricValueTypeInt in switch on exemplar.ValueType() (mismatched types "go.opentelemetry.io/collector/pdata/internal".NumberDataPointValueType and "go.opentelemetry.io/collector/pdata/internal".ExemplarValueType)
pkg/translator/opencensus/metrics_to_oc.go:371:3: invalid case pmetric.MetricValueTypeDouble in switch on exemplar.ValueType() (mismatched types "go.opentelemetry.io/collector/pdata/internal".NumberDataPointValueType and "go.opentelemetry.io/collector/pdata/internal".ExemplarValueType)
FAIL	github.com/open-telemetry/opentelemetry-collector-contrib/internal/components [build failed]

[dmitryax]

contrib-tests failure is expected. It will be fixed once open-telemetry/opentelemetry-collector-contrib#9389 is merged

[hanjm]

@bogdandrutu Rebase done, Please help review, thank you.