[Perf] Windows/x86: 3 Improvements on 7/6/2026 7:38:21 AM +00:00

### Run Information

Name | Value
-- | --
Architecture | x86
OS | Windows 10.0.22631
Queue | ViperWindows
Baseline | [8f365c934088b8ae21a4dfce8073da0d3eb22a54](https://github.com/dotnet/runtime/commit/8f365c934088b8ae21a4dfce8073da0d3eb22a54)
Compare | [c473d80e67a0e090fa4a3e67fbc5bc9d122b172a](https://github.com/dotnet/runtime/commit/c473d80e67a0e090fa4a3e67fbc5bc9d122b172a)
Diff | [Diff](https://github.com/dotnet/runtime/compare/8f365c934088b8ae21a4dfce8073da0d3eb22a54...c473d80e67a0e090fa4a3e67fbc5bc9d122b172a)
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
-- | -- | -- | -- | -- | -- | -- | -- | --
|

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

| 117.69 ns | 98.01 ns | 0.83 | 0.17 | False | | |
|

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

| 4.57 ms | 3.92 ms | 0.86 | 0.11 | 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.Tests.Perf_String*'
```

### System.Tests.Perf_String.IndexerCheckPathLength

#### ETL Files

#### Histogram

#### JIT Disasms

### 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 | [8f365c934088b8ae21a4dfce8073da0d3eb22a54](https://github.com/dotnet/runtime/commit/8f365c934088b8ae21a4dfce8073da0d3eb22a54)
Compare | [c473d80e67a0e090fa4a3e67fbc5bc9d122b172a](https://github.com/dotnet/runtime/commit/c473d80e67a0e090fa4a3e67fbc5bc9d122b172a)
Diff | [Diff](https://github.com/dotnet/runtime/compare/8f365c934088b8ae21a4dfce8073da0d3eb22a54...c473d80e67a0e090fa4a3e67fbc5bc9d122b172a)
Configs | CompilationMode:tiered, RunKind:micro

### Improvements in System.Linq.Tests.Perf_Enumerable

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

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

| 239.57 ns | 205.21 ns | 0.86 | 0.34 | 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.Linq.Tests.Perf_Enumerable*'
```

### System.Linq.Tests.Perf_Enumerable.SelectToArray(input: List)

#### 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 in src/benchmarks/micro/libraries/System.Runtime/Perf.String.cs and src/benchmarks/micro/libraries/System.Linq/Perf.Enumerable.cs, then run the provided benchmarks_ci.py commands. Compare results with the linked baseline and compare commits; done should mean the reported Windows/x86 measurements are reproduced and any resulting change is validated.

Written by the indexing model from the issue text.