[Do not merge] [otlp] Benchmarks comparison manual vs google protobuf serialization.

[rajkumar-rangaraj]

Benchmark results

BenchmarkDotNet v0.13.12, Windows 11 (10.0.22631.4460/23H2/2023Update/SunValley3) (Hyper-V)
AMD EPYC 7763, 1 CPU, 16 logical and 8 physical cores
.NET SDK 9.0.100
  [Host]     : .NET 9.0.0 (9.0.24.52809), X64 RyuJIT AVX2
  DefaultJob : .NET 9.0.0 (9.0.24.52809), X64 RyuJIT AVX2

OtlpHttpExporterBenchmarks - Old

Method	NumberOfBatches	NumberOfSpans	Mean	Error	StdDev	Gen0	Gen1	Gen2	Allocated
OtlpExporter_Batching	1	10000	49.02 ms	0.272 ms	0.212 ms	1272.7273	1181.8182	181.8182	20.47 MB
OtlpExporter_Batching	10	10000	498.89 ms	9.109 ms	8.521 ms	12000.0000	11000.0000	2000.0000	204.66 MB
OtlpExporter_Batching	100	10000	5,128.04 ms	20.363 ms	17.004 ms	134000.0000	132000.0000	27000.0000	2046.63 MB

ProtobufOtlpHttpExporterBenchmarks - New

Method	NumberOfBatches	NumberOfSpans	Mean	Error	StdDev	Allocated
OtlpExporter_Batching	1	10000	1.725 ms	0.0328 ms	0.0365 ms	1.85 KB
OtlpExporter_Batching	10	10000	16.593 ms	0.1462 ms	0.1296 ms	18.55 KB
OtlpExporter_Batching	100	10000	165.445 ms	0.6541 ms	0.5799 ms	185.83 KB

OtlpGrpcExporterBenchmarks - Old

Method	NumberOfBatches	NumberOfSpans	Mean	Error	StdDev	Gen0	Gen1	Gen2	Allocated
OtlpExporter_Batching	1	10000	21.50 ms	0.422 ms	0.564 ms	1312.5000	1281.2500	250.0000	20.45 MB
OtlpExporter_Batching	10	10000	203.13 ms	3.879 ms	3.628 ms	13000.0000	12666.6667	2666.6667	204.48 MB
OtlpExporter_Batching	100	10000	2,061.70 ms	23.189 ms	20.556 ms	133000.0000	131000.0000	26000.0000	2044.77 MB

ProtobufOtlpGrpcExporterBenchmarks - New

Method	NumberOfBatches	NumberOfSpans	Mean	Error	StdDev	Allocated
OtlpExporter_Batching	1	10000	1.693 ms	0.0065 ms	0.0058 ms	1.85 KB
OtlpExporter_Batching	10	10000	16.688 ms	0.1453 ms	0.1288 ms	18.55 KB
OtlpExporter_Batching	100	10000	161.766 ms	0.2498 ms	0.2086 ms	185.58 KB

OtlpTraceExporterBenchmarks

Method	Mean	Error	StdDev	Median	Gen0	Gen1	Allocated
OtlpTraceExporter_Http	91.14 μs	1.643 μs	3.003 μs	90.28 μs	0.4883	0.2441	9.55 KB
OtlpTraceExporter_Grpc	138.50 μs	2.740 μs	7.453 μs	135.60 μs	0.4883	-	8.99 KB
ProtobufOtlpTraceExporter_Http	98.36 μs	1.957 μs	4.213 μs	99.72 μs	0.2441	-	5.03 KB
ProtobufOtlpTraceExporter_Grpc	117.71 μs	1.323 μs	1.173 μs	117.78 μs	-	-	6.56 KB

OtlpLogExporterBenchmarks

Method	Mean	Error	StdDev	Gen0	Gen1	Allocated
OtlpLogExporter_Http	91.62 μs	1.162 μs	0.970 μs	0.4883	0.2441	9.55 KB
OtlpLogExporter_Grpc	140.87 μs	2.774 μs	4.558 μs	0.4883	-	9 KB
ProtobufOtlpLogExporter_Http	90.45 μs	1.735 μs	2.255 μs	0.2441	-	5.03 KB
ProtobufOtlpLogExporter_Grpc	111.99 μs	2.232 μs	3.130 μs	-	-	5.08 KB

Note:

CreateHttpRequest in ProtobufOtlpHttpExportClient and equivalent in Grpc are allocating memory with new implementation. I tried caching the HttpRequestMessage where the allocation went below 1 KB. But we cannot use caching here as HttpRequestMessage is designed to be recreated always. As a follow up we will work to enhance this method to avoid the allocation. Reference:

opentelemetry-dotnet/src/OpenTelemetry.Exporter.OpenTelemetryProtocol/Implementation/ExportClient/ProtobufOtlpHttpExportClient.cs

Line 82 in f9a0b4c

public HttpRequestMessage CreateHttpRequest(byte[] exportRequest, int contentLength)

opentelemetry-dotnet/src/OpenTelemetry.Exporter.OpenTelemetryProtocol/Implementation/ExportClient/ProtobufOtlpGrpcExportClient.cs

Line 69 in f9a0b4c

public HttpRequestMessage CreateHttpRequest(byte[] buffer, int contentLength)

Merge requirement checklist

• CONTRIBUTING guidelines followed (license requirements, nullable enabled, static analysis, etc.)
• Unit tests added/updated
• Appropriate CHANGELOG.md files updated for non-trivial changes
• Changes in public API reviewed (if applicable)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 84.00%. Comparing base (e3665c9) to head (8e2932e).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5999      +/-   ##
==========================================
- Coverage   84.14%   84.00%   -0.14%     
==========================================
  Files         275      275              
  Lines       12560    12582      +22     
==========================================
+ Hits        10569    10570       +1     
- Misses       1991     2012      +21     

Flag	Coverage Δ
unittests-Project-Experimental	83.71% <ø> (-0.40%)	⬇️
unittests-Project-Stable	83.98% <ø> (-0.06%)	⬇️

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see 11 files with indirect coverage changes

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