[Perf] Linux/arm64: 2 Regressions on 7/23/2026 7:09:44 PM +00:00

### Run Information

Name | Value
-- | --
Architecture | arm64
OS | azurelinux 3.0
Queue | CobaltAzureLinux
Baseline | [3e64752d437bc3429276c0cd019f30e6d4088d1f](https://github.com/dotnet/runtime/commit/3e64752d437bc3429276c0cd019f30e6d4088d1f)
Compare | [3a76b784148f79d59ac241c643643f57c517b3a3](https://github.com/dotnet/runtime/commit/3a76b784148f79d59ac241c643643f57c517b3a3)
Diff | [Diff](https://github.com/dotnet/runtime/compare/3e64752d437bc3429276c0cd019f30e6d4088d1f...3a76b784148f79d59ac241c643643f57c517b3a3)
Configs | CompilationMode:tiered, RunKind:micro

### Regressions in System.Globalization.Tests.StringEquality

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

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

| 996.78 ns | 1808.69 ns | 1.81 | 0.17 | 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.Globalization.Tests.StringEquality*'
```

### System.Globalization.Tests.StringEquality.Compare_Same(Count: 1024, Options: (en-US, OrdinalIgnoreCase))

#### 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 | arm64
OS | azurelinux 3.0
Queue | CobaltAzureLinux
Baseline | [3e64752d437bc3429276c0cd019f30e6d4088d1f](https://github.com/dotnet/runtime/commit/3e64752d437bc3429276c0cd019f30e6d4088d1f)
Compare | [3a76b784148f79d59ac241c643643f57c517b3a3](https://github.com/dotnet/runtime/commit/3a76b784148f79d59ac241c643643f57c517b3a3)
Diff | [Diff](https://github.com/dotnet/runtime/compare/3e64752d437bc3429276c0cd019f30e6d4088d1f...3a76b784148f79d59ac241c643643f57c517b3a3)
Configs | CompilationMode:tiered, RunKind:micro

### Regressions in Benchmark.GetChildKeysTests

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

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

| 16.40 ms | 21.76 ms | 1.33 | 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 'Benchmark.GetChildKeysTests*'
```

### Benchmark.GetChildKeysTests.AddChainedConfigurationEmpty

#### 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 linked benchmark sources, src/benchmarks/micro/libraries/System.Globalization/StringEquality.cs and src/benchmarks/micro/libraries/Microsoft.Extensions.Configuration/GetChildKeysTests.cs, and read the benchmarking workflow documentation. Run the provided filters on Linux/arm64, compare the reported baselines with the test results, and determine what changed between the linked commits. Done means both reported regressions are explained and the performance regressions no longer reproduce.

Written by the indexing model from the issue text.