[Perf] Linux/arm64: 3 Regressions on 6/23/2026 1:15:15 AM +00:00

### Run Information

Name | Value
-- | --
Architecture | arm64
OS | ubuntu 22.04
Queue | AmpereUbuntu
Baseline | [8c4e8067d2e916f6673197b0c12ba5e2dcb593ee](https://github.com/dotnet/runtime/commit/8c4e8067d2e916f6673197b0c12ba5e2dcb593ee)
Compare | [34103fc653c1c3afa8b6bfb82544c5bca826ead8](https://github.com/dotnet/runtime/commit/34103fc653c1c3afa8b6bfb82544c5bca826ead8)
Diff | [Diff](https://github.com/dotnet/runtime/compare/8c4e8067d2e916f6673197b0c12ba5e2dcb593ee...34103fc653c1c3afa8b6bfb82544c5bca826ead8)
Configs | CompilationMode:tiered, RunKind:micro

### Regressions in System.Globalization.Tests.StringSearch

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

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

| 502.43 ns | 535.43 ns | 1.07 | 0.01 | False | | |
|

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

| 502.44 ns | 535.37 ns | 1.07 | 0.02 | False | | |
|

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

| 502.91 ns | 535.58 ns | 1.06 | 0.01 | False | | |

![graph]()
![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
python3 .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Globalization.Tests.StringSearch*'
```

### System.Globalization.Tests.StringSearch.IndexOf_Word_NotFound(Options: (en-US, None, False))

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Globalization.Tests.StringSearch.IndexOf_Word_NotFound(Options: (en-US, IgnoreNonSpace, False))

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Globalization.Tests.StringSearch.IndexOf_Word_NotFound(Options: (, None, False))

#### 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)