[Perf] Windows/x86: 3 Improvements on 7/2/2026 11:21:29 PM +00:00

### Run Information

Name | Value
-- | --
Architecture | x86
OS | Windows 10.0.22631
Queue | ViperWindows
Baseline | [901aeddd1c55f5fc5a1c1450f234dd954c430ea5](https://github.com/dotnet/runtime/commit/901aeddd1c55f5fc5a1c1450f234dd954c430ea5)
Compare | [e1979b72ccb5f916649f1d9949ef663254790c25](https://github.com/dotnet/runtime/commit/e1979b72ccb5f916649f1d9949ef663254790c25)
Diff | [Diff](https://github.com/dotnet/runtime/compare/901aeddd1c55f5fc5a1c1450f234dd954c430ea5...e1979b72ccb5f916649f1d9949ef663254790c25)
Configs | CompilationMode:tiered, RunKind:micro

### Improvements in PerfLabTests.LowLevelPerf

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

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

| 1.41 ms | 1.14 ms | 0.81 | 0.20 | 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 'PerfLabTests.LowLevelPerf*'
```

### PerfLabTests.LowLevelPerf.EmptyStaticFunction

#### 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 | [901aeddd1c55f5fc5a1c1450f234dd954c430ea5](https://github.com/dotnet/runtime/commit/901aeddd1c55f5fc5a1c1450f234dd954c430ea5)
Compare | [e1979b72ccb5f916649f1d9949ef663254790c25](https://github.com/dotnet/runtime/commit/e1979b72ccb5f916649f1d9949ef663254790c25)
Diff | [Diff](https://github.com/dotnet/runtime/compare/901aeddd1c55f5fc5a1c1450f234dd954c430ea5...e1979b72ccb5f916649f1d9949ef663254790c25)
Configs | CompilationMode:tiered, RunKind:micro

### Improvements in System.Tests.Perf_String

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

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

| 4.58 ms | 3.97 ms | 0.87 | 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.Tests.Perf_String*'
```

### System.Tests.Perf_String.Split_Csv(testName: "Short Text", lines: ["Year,quarter,Bene_Geo_Desc,Bene_Mdcd_Mdcr_Enrl_Stus,Bene_Race_Desc,Bene_Sex_Desc,Bene_Mdcr_Entlmt_Stus,Bene_Age_Desc,Bene_RUCA_Desc,Total_Bene_TH_Elig,Total_PartB_Enrl,Total_Bene_Telehealth,Pct_Telehealth", "2020,Overall,National,All,All,All,All,All,All,30946785,32244893.5,14826919,0.4791", "2020,Overall,National,All,All,All,All,All,Rural,7179538,7490300.6667,2858284,0.3981", "2020,Overall,National,All,All,All,All,All,Urban,23696871,24629142.917,11944230,0.504", "2020,Overall,National,All,All,All,All,All,Unknown,,,,", ...])

#### 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 | [901aeddd1c55f5fc5a1c1450f234dd954c430ea5](https://github.com/dotnet/runtime/commit/901aeddd1c55f5fc5a1c1450f234dd954c430ea5)
Compare | [e1979b72ccb5f916649f1d9949ef663254790c25](https://github.com/dotnet/runtime/commit/e1979b72ccb5f916649f1d9949ef663254790c25)
Diff | [Diff](https://github.com/dotnet/runtime/compare/901aeddd1c55f5fc5a1c1450f234dd954c430ea5...e1979b72ccb5f916649f1d9949ef663254790c25)
Configs | CompilationMode:tiered, RunKind:micro

### Improvements in System.IO.Tests.StreamReaderReadToEndTests

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

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

| 164.89 ms | 154.35 ms | 0.94 | 0.11 | 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.IO.Tests.StreamReaderReadToEndTests*'
```

### System.IO.Tests.StreamReaderReadToEndTests.ReadToEndAsync(LineLengthRange: [ 9, 32])

#### 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 named in src/benchmarks/micro/runtime/perflab/LowLevelPerf.cs, src/benchmarks/micro/libraries/System.Runtime/Perf.String.cs, and src/benchmarks/micro/libraries/System.IO/StreamReaderReadToEndTests.cs. Reproduce each report with benchmarks_ci.py and its listed filter on Windows/x86. The issue does not define a code change; completion would require identifying an owner-approved improvement and validating it with the affected benchmarks.

Written by the indexing model from the issue text.