[Perf] Linux/x64: 1 Regression on 6/15/2026 1:41:54 PM +00:00

### Run Information

Name | Value
-- | --
Architecture | x64
OS | ubuntu 22.04
Queue | ViperUbuntu
Baseline | [b8e08206ff30224fc4445f8f8e545194948290ea](https://github.com/dotnet/runtime/commit/b8e08206ff30224fc4445f8f8e545194948290ea)
Compare | [fd3a4f4683bb4adda7785506b9a8fc5c2607b422](https://github.com/dotnet/runtime/commit/fd3a4f4683bb4adda7785506b9a8fc5c2607b422)
Diff | [Diff](https://github.com/dotnet/runtime/compare/b8e08206ff30224fc4445f8f8e545194948290ea...fd3a4f4683bb4adda7785506b9a8fc5c2607b422)
Configs | CompilationMode:wasm, RunKind:micro, RuntimeType:coreclr

### Regressions in System.Collections.IndexerSet<String>

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

• [IList - 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.Collections.IndexerSet*'
```

### System.Collections.IndexerSet<String>.IList(Size: 512)

#### 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 benchmark source at src/benchmarks/micro/libraries/System.Collections/Indexer/IndexerSet.cs#L70-L72 and run the documented benchmarks_ci.py command for System.Collections.IndexerSet.IList. Compare the baseline and test commits, then use the linked test report and profiling workflow to identify the regression; done means the performance regression is explained and addressed.

Written by the indexing model from the issue text.