[Perf] Linux/x64: 1 Improvement on 8/31/2026 6:13:39 PM +00:00

### Run Information

Name | Value
-- | --
Architecture | x64
OS | ubuntu 22.04
Queue | ViperUbuntu
Baseline | [b030ed4ffa9ede39fbe59d1eb379e4a6e42050c1](https://github.com/dotnet/runtime/commit/b030ed4ffa9ede39fbe59d1eb379e4a6e42050c1)
Compare | [bdcba57531224815fbbc0fbb5ee23a1d3876d43a](https://github.com/dotnet/runtime/commit/bdcba57531224815fbbc0fbb5ee23a1d3876d43a)
Diff | [Diff](https://github.com/dotnet/runtime/compare/b030ed4ffa9ede39fbe59d1eb379e4a6e42050c1...bdcba57531224815fbbc0fbb5ee23a1d3876d43a)
Configs | CompilationMode:wasm, RunKind:micro, RuntimeType:coreclr

### Improvements in System.Collections.CtorDefaultSize<Int32>

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

• [ConcurrentDictionary - 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.CtorDefaultSize*'
```

### System.Collections.CtorDefaultSize<Int32>.ConcurrentDictionary

#### 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 Source, src/benchmarks/micro/libraries/System.Collections/Create/CtorDefaultSize.cs, and compare the Baseline and Compare commits. Run the documented benchmarks_ci.py command for System.Collections.CtorDefaultSize* and inspect the linked test report and IR data. Done means explaining or addressing the reported ConcurrentDictionary performance change.

Written by the indexing model from the issue text.