[Perf] Linux/arm64: 1 Regression on 7/17/2026 3:20:10 PM +00:00

### Run Information

Name | Value
-- | --
Architecture | arm64
OS | azurelinux 3.0
Queue | CobaltAzureLinux
Baseline | [509acfd47f3cbbaeddb6a49edadaedb8fdfdf9ad](https://github.com/dotnet/runtime/commit/509acfd47f3cbbaeddb6a49edadaedb8fdfdf9ad)
Compare | [1c124aa4de6f37b96572de3d429a611260a29a23](https://github.com/dotnet/runtime/commit/1c124aa4de6f37b96572de3d429a611260a29a23)
Diff | [Diff](https://github.com/dotnet/runtime/compare/509acfd47f3cbbaeddb6a49edadaedb8fdfdf9ad...1c124aa4de6f37b96572de3d429a611260a29a23)
Configs | CompilationMode:tiered, R2RType:r2r_interpreter, RunKind:micro

### Regressions in System.Numerics.Tests.Perf_VectorOf<UInt16>

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

• [SquareRootBenchmark - 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.Numerics.Tests.Perf_VectorOf*'
```

### System.Numerics.Tests.Perf_VectorOf<UInt16>.SquareRootBenchmark

#### 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 System.Numerics.Tests.Perf_VectorOfT.cs benchmark source around SquareRootBenchmark and reproduce it with the provided benchmarks_ci.py command. Compare the arm64 AzureLinux3 result against the listed baseline and compare commits. Done means the regression is explained and the benchmark no longer shows the reported slowdown.

Written by the indexing model from the issue text.