[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 reproduce it using scripts/benchmarks_ci.py with the documented filter. Compare the baseline and test commits, then use the linked performance and profiling reports to investigate the AOT WebAssembly regression. Done means the regression is explained and addressed, with the benchmark result checked again.

Written by the indexing model from the issue text.