[Perf] Linux/x64: 1 Regression on 6/28/2026 9:49:46 PM +00:00

### Run Information

Name | Value
-- | --
Architecture | x64
OS | ubuntu 22.04
Queue | ViperUbuntu
Baseline | [33db1610a13c814c71deb0865a23927305eecb5a](https://github.com/dotnet/runtime/commit/33db1610a13c814c71deb0865a23927305eecb5a)
Compare | [0d3df07c6048d8cbe4f544227462cae62040e587](https://github.com/dotnet/runtime/commit/0d3df07c6048d8cbe4f544227462cae62040e587)
Diff | [Diff](https://github.com/dotnet/runtime/compare/33db1610a13c814c71deb0865a23927305eecb5a...0d3df07c6048d8cbe4f544227462cae62040e587)
Configs | CompilationMode:tiered, RunKind:micro

### Regressions in System.Text.Json.Serialization.Tests.WriteJson<ClassRecord>

Benchmark | Baseline | Test | Test/Base | Test Quality | Edge Detector | Baseline IR | Compare IR | IR Ratio
-- | -- | -- | -- | -- | -- | -- | -- | --
|

• [SerializeToWriter - Duration of single invocation]()
• 📝 - [Benchmark Source]()
• [ADX - Test Multi Config Graph]()

![graph]()
[Test Report]()

### Repro
General Docs link: https://github.com/dotnet/performance/blob/main/docs/benchmarking-workflow-dotnet-runtime.md

```cmd
git clone https://github.com/dotnet/performance.git
python3 .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Text.Json.Serialization.Tests.WriteJson*'
```

### System.Text.Json.Serialization.Tests.WriteJson<ClassRecord>.SerializeToWriter(Mode: SourceGen)

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

[Profiling workflow for dotnet/runtime repository](https://github.com/dotnet/performance/blob/master/docs/profiling-workflow-dotnet-runtime.md)
[Benchmarking workflow for dotnet/runtime repository](https://github.com/dotnet/performance/blob/master/docs/benchmarking-workflow-dotnet-runtime.md)

Start with the benchmark source at src/benchmarks/micro/libraries/System.Text.Json/Serializer/WriteJson.cs lines 81-87 and reproduce it using the provided benchmarks_ci.py command. Compare the baseline and test results for SerializeToWriter(ClassRecord) in the linked report; done means the reported regression is explained or corrected and the benchmark result is verified.

Written by the indexing model from the issue text.