Repository navigation
[Perf] System.Text.Json.Serialization Regressions on 7/21/2025 11:54:44 PM +00:00 #118173
Description
Run Information
| Name | Value |
|---|---|
| Architecture | x64 |
| OS | Windows 10.0.22621 |
| Queue | TigerWindows |
| Baseline | 959c2a7a782b4e9e698e0f00cb06afe859d16829 |
| Compare | 0b2f272204ea0cb7d22d329a684c06cec412f736 |
| Diff | Diff |
| Configs | CompilationMode:tiered, RunKind:micro |
Regressions in System.Text.Json.Serialization.Tests.ReadJson<Int32>
| Benchmark | Baseline | Test | Test/Base | Test Quality | Edge Detector | Baseline IR | Compare IR | IR Ratio |
|---|---|---|---|---|---|---|---|---|
| 212.45 ns | 243.45 ns | 1.15 | 0.06 | False | ||||
| 211.55 ns | 239.08 ns | 1.13 | 0.05 | False |
Repro
General Docs link: https://github.com/dotnet/performance/blob/main/docs/benchmarking-workflow-dotnet-runtime.md
git clone https://github.com/dotnet/performance.git
py .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Text.Json.Serialization.Tests.ReadJson<Int32>*'Details
System.Text.Json.Serialization.Tests.ReadJson<Int32>.DeserializeFromStream(Mode: SourceGen)
ETL Files
Histogram
JIT Disasms
System.Text.Json.Serialization.Tests.ReadJson<Int32>.DeserializeFromStream(Mode: Reflection)
ETL Files
Histogram
JIT Disasms
Docs
Profiling workflow for dotnet/runtime repository
Benchmarking workflow for dotnet/runtime repository
Run Information
| Name | Value |
|---|---|
| Architecture | x64 |
| OS | Windows 10.0.22621 |
| Queue | TigerWindows |
| Baseline | 959c2a7a782b4e9e698e0f00cb06afe859d16829 |
| Compare | 0b2f272204ea0cb7d22d329a684c06cec412f736 |
| Diff | Diff |
| Configs | CompilationMode:tiered, RunKind:micro |
Regressions in System.Text.Json.Serialization.Tests.ReadJson<Nullable<DateTimeOffset>>
| Benchmark | Baseline | Test | Test/Base | Test Quality | Edge Detector | Baseline IR | Compare IR | IR Ratio |
|---|---|---|---|---|---|---|---|---|
| 276.53 ns | 292.65 ns | 1.06 | 0.05 | False |
Repro
General Docs link: https://github.com/dotnet/performance/blob/main/docs/benchmarking-workflow-dotnet-runtime.md
git clone https://github.com/dotnet/performance.git
py .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Text.Json.Serialization.Tests.ReadJson<Nullable<DateTimeOffset>>*'Details
System.Text.Json.Serialization.Tests.ReadJson<Nullable<DateTimeOffset>>.DeserializeFromStream(Mode: SourceGen)
ETL Files
Histogram
JIT Disasms
Docs
Profiling workflow for dotnet/runtime repository
Benchmarking workflow for dotnet/runtime repository
Run Information
| Name | Value |
|---|---|
| Architecture | x64 |
| OS | Windows 10.0.22621 |
| Queue | TigerWindows |
| Baseline | 88f2361c958affeaaa24122780fecb680365b558 |
| Compare | 0b2f272204ea0cb7d22d329a684c06cec412f736 |
| Diff | Diff |
| Configs | CompilationMode:tiered, RunKind:micro |
Regressions in MicroBenchmarks.Serializers.Json_FromStream<LoginViewModel>
| Benchmark | Baseline | Test | Test/Base | Test Quality | Edge Detector | Baseline IR | Compare IR | IR Ratio |
|---|---|---|---|---|---|---|---|---|
| 359.87 ns | 382.93 ns | 1.06 | 0.01 | False |
Repro
General Docs link: https://github.com/dotnet/performance/blob/main/docs/benchmarking-workflow-dotnet-runtime.md
git clone https://github.com/dotnet/performance.git
py .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'MicroBenchmarks.Serializers.Json_FromStream<LoginViewModel>*'Details
MicroBenchmarks.Serializers.Json_FromStream<LoginViewModel>.SystemTextJson_SourceGen_
ETL Files
Histogram
JIT Disasms
Docs
Profiling workflow for dotnet/runtime repository
Benchmarking workflow for dotnet/runtime repository
Activity
LoopedBard3 commentedon Jul 29, 2025
Likely due to #116947 in range a6a3475...4314b63. FYI @BrennanConroy. Related Regressions:
[-][Perf] Windows/x64: 4 Regressions on 7/21/2025 11:54:44 PM +00:00[/-][+][Perf] System.Text.Json.Serialization Regressions on 7/21/2025 11:54:44 PM +00:00[/+]dotnet-policy-service commentedon Jul 29, 2025
Tagging subscribers to this area: @dotnet/area-system-text-json, @gregsdennis
See info in area-owners.md if you want to be subscribed.
jeffhandley commentedon Aug 4, 2025
@BrennanConroy I assigned this to you for evaluation before we close down .NET 10. Please connect with @eiriktsarpalis to make sure the tradeoff is acceptable here or consider ways to mitigate the regression if caused by #116947.
jeffhandley commentedon Aug 30, 2025
The reports are still showing the regression; it doesn't look like #118408 addressed this.
jeffhandley commentedon Sep 25, 2025
Closing this as an accepted diff