[Perf] Windows/x86: 2 Improvements on 7/7/2026 8:36:41 AM +00:00

### Run Information

Name | Value
-- | --
Architecture | x86
OS | Windows 10.0.22631
Queue | ViperWindows
Baseline | [22439c05e7608d5396e0b55144849f360d7b5475](https://github.com/dotnet/runtime/commit/22439c05e7608d5396e0b55144849f360d7b5475)
Compare | [5568a01aa964e9f6784490f9359135cc36d021fa](https://github.com/dotnet/runtime/commit/5568a01aa964e9f6784490f9359135cc36d021fa)
Diff | [Diff](https://github.com/dotnet/runtime/compare/22439c05e7608d5396e0b55144849f360d7b5475...5568a01aa964e9f6784490f9359135cc36d021fa)
Configs | CompilationMode:tiered, RunKind:micro

### Improvements in System.IO.Tests.StreamReaderReadLineTests

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

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

| 132.55 μs | 108.55 μs | 0.82 | 0.30 | False | | |
|

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

| 221.50 μs | 196.95 μs | 0.89 | 0.06 | False | | |

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

### System.IO.Tests.StreamReaderReadLineTests.ReadLineAsync(LineLengthRange: [ 1, 8])

#### ETL Files

#### Histogram

#### JIT Disasms

### System.IO.Tests.StreamReaderReadLineTests.ReadLineAsync(LineLengthRange: [ 1, 1])

#### 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 dotnet/performance/src/benchmarks/micro/libraries/System.IO/StreamReaderReadLineTests.cs and read the benchmarking workflow linked in the issue. Run the provided benchmarks with the StreamReaderReadLineTests filter, then compare the x86 Windows results against the listed baseline and comparison commits. Done means the reported performance change is explained and an appropriate runtime improvement or follow-up is verified.

Written by the indexing model from the issue text.