[Perf] Windows/x64: 2 Improvements on 2/3/2026 2:30:42 AM +00:00

### Run Information

Name | Value
-- | --
Architecture | x64
OS | Windows 10.0.22631
Queue | ViperWindows
Baseline | [918254d67350876df8f9e474195ef359a7ce33f6](https://github.com/dotnet/runtime/commit/918254d67350876df8f9e474195ef359a7ce33f6)
Compare | [39580bd95b3a75f6a304f05d2117ae72ec0c53a3](https://github.com/dotnet/runtime/commit/39580bd95b3a75f6a304f05d2117ae72ec0c53a3)
Diff | [Diff](https://github.com/dotnet/runtime/compare/918254d67350876df8f9e474195ef359a7ce33f6...39580bd95b3a75f6a304f05d2117ae72ec0c53a3)
Configs | CompilationMode:tiered, RunKind:micro

### Improvements in System.Text.Json.Document.Tests.Perf_EnumerateArray

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

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

| 5.05 μs | 4.72 μs | 0.93 | 0.01 | 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.Document.Tests.Perf_EnumerateArray*'
```

### System.Text.Json.Document.Tests.Perf_EnumerateArray.Parse(TestCase: ArrayOfNumbers)

#### 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 | x64
OS | Windows 10.0.22631
Queue | ViperWindows
Baseline | [918254d67350876df8f9e474195ef359a7ce33f6](https://github.com/dotnet/runtime/commit/918254d67350876df8f9e474195ef359a7ce33f6)
Compare | [39580bd95b3a75f6a304f05d2117ae72ec0c53a3](https://github.com/dotnet/runtime/commit/39580bd95b3a75f6a304f05d2117ae72ec0c53a3)
Diff | [Diff](https://github.com/dotnet/runtime/compare/918254d67350876df8f9e474195ef359a7ce33f6...39580bd95b3a75f6a304f05d2117ae72ec0c53a3)
Configs | CompilationMode:tiered, RunKind:micro

### Improvements in System.Text.Json.Tests.Perf_Reader

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

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

| 1.10 μs | 1.03 μs | 0.94 | 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.Text.Json.Tests.Perf_Reader*'
```

### System.Text.Json.Tests.Perf_Reader.ReadSingleSpanSequenceEmptyLoop(IsDataCompact: True, TestCase: LotsOfNumbers)

#### 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 sources at src/benchmarks/micro/libraries/System.Text.Json/Document/EnumerateArray.cs and src/benchmarks/micro/libraries/System.Text.Json/Utf8JsonReader/Perf.Reader.cs. Run the provided benchmarks_ci.py filters and review the linked reports and baseline/compare commits to determine whether the reported improvements require follow-up; done means the performance result is triaged with a documented conclusion.

Written by the indexing model from the issue text.