[Perf] Linux/x64: 1 Regression on 6/25/2026 12:43:10 AM +00:00

### Run Information

Name | Value
-- | --
Architecture | x64
OS | ubuntu 22.04
Queue | ViperUbuntu
Baseline | [9c1fdaea7e4595785db31a5a219f66fb7d2a4ec1](https://github.com/dotnet/runtime/commit/9c1fdaea7e4595785db31a5a219f66fb7d2a4ec1)
Compare | [818cfd5edcda78ac3eb201af392fd301ab9ad46b](https://github.com/dotnet/runtime/commit/818cfd5edcda78ac3eb201af392fd301ab9ad46b)
Diff | [Diff](https://github.com/dotnet/runtime/compare/9c1fdaea7e4595785db31a5a219f66fb7d2a4ec1...818cfd5edcda78ac3eb201af392fd301ab9ad46b)
Configs | AOT:true, CompilationMode:wasm, RunKind:micro

### Regressions in System.Reflection.Attributes

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

• [IsDefinedMethodBaseMiss - 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
python3 .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Reflection.Attributes*'
```

### System.Reflection.Attributes.IsDefinedMethodBaseMiss

#### 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.Reflection.Attributes.IsDefinedMethodBaseMiss benchmark source at src/benchmarks/micro/runtime/System.Reflection/Attributes.cs#L120-L121 and compare the listed baseline and compare commits. Run benchmarks_ci.py with the System.Reflection.Attributes* filter, then use the linked test report and graph to confirm the regression and identify its cause; done means the regression is understood and addressed.

Written by the indexing model from the issue text.