[Perf] Windows/x86: 2 Regressions on 5/28/2026 7:26:44 AM +00:00

### Run Information

Name | Value
-- | --
Architecture | x86
OS | Windows 10.0.22631
Queue | ViperWindows
Baseline | [2a546738e968e3f75092657d4bee6bd21821e069](https://github.com/dotnet/runtime/commit/2a546738e968e3f75092657d4bee6bd21821e069)
Compare | [54cfeb453970e794043c71448a60a39b4fee3a38](https://github.com/dotnet/runtime/commit/54cfeb453970e794043c71448a60a39b4fee3a38)
Diff | [Diff](https://github.com/dotnet/runtime/compare/2a546738e968e3f75092657d4bee6bd21821e069...54cfeb453970e794043c71448a60a39b4fee3a38)
Configs | CompilationMode:tiered, RunKind:micro

### Regressions in System.Text.Json.Tests.Perf_Strings

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

• [WriteStringsUtf16 - Duration of single invocation]()
• 📝 - [Benchmark Source]()
• [ADX - Test Multi Config Graph]()

| 38.19 ms | 40.68 ms | 1.07 | 0.10 | False | | |

![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
py .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Text.Json.Tests.Perf_Strings*'
```

### System.Text.Json.Tests.Perf_Strings.WriteStringsUtf16(Formatted: True, SkipValidation: False, Escaped: AllEscaped)

#### 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)

---

### Run Information

Name | Value
-- | --
Architecture | x86
OS | Windows 10.0.22631
Queue | ViperWindows
Baseline | [2a546738e968e3f75092657d4bee6bd21821e069](https://github.com/dotnet/runtime/commit/2a546738e968e3f75092657d4bee6bd21821e069)
Compare | [54cfeb453970e794043c71448a60a39b4fee3a38](https://github.com/dotnet/runtime/commit/54cfeb453970e794043c71448a60a39b4fee3a38)
Diff | [Diff](https://github.com/dotnet/runtime/compare/2a546738e968e3f75092657d4bee6bd21821e069...54cfeb453970e794043c71448a60a39b4fee3a38)
Configs | CompilationMode:tiered, RunKind:micro

### Regressions in System.Tests.Perf_String

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

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

| 247.34 ns | 262.58 ns | 1.06 | 0.04 | False | | |

![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
py .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Tests.Perf_String*'
```

### System.Tests.Perf_String.Split(s: "A B C D E F G H I J K L M N O P Q R S T U V W X Y Z", arr: [' '], options: None)

#### 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)