[Perf] Linux/arm64: 1 Regression on 5/20/2026 9:51:13 AM +00:00

### Run Information

Name | Value
-- | --
Architecture | arm64
OS | azurelinux 3.0
Queue | CobaltAzureLinux
Baseline | [f397c835cc1c655505d2a22fd0cebb9e96733d0b](https://github.com/dotnet/runtime/commit/f397c835cc1c655505d2a22fd0cebb9e96733d0b)
Compare | [a49d0cf4bb262a0bb8a2ece002155cd0a4829dbd](https://github.com/dotnet/runtime/commit/a49d0cf4bb262a0bb8a2ece002155cd0a4829dbd)
Diff | [Diff](https://github.com/dotnet/runtime/compare/f397c835cc1c655505d2a22fd0cebb9e96733d0b...a49d0cf4bb262a0bb8a2ece002155cd0a4829dbd)
Configs | CompilationMode:tiered, RunKind:micro

### Regressions in System.Text.Tests.Perf_StringBuilder

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

• [ctor_capacity - Duration of single invocation]()
• 📝 - [Benchmark Source]()
• [ADX - Test Multi Config 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.Text.Tests.Perf_StringBuilder*'
```

### System.Text.Tests.Perf_StringBuilder.ctor_capacity(length: 100000)

#### 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)