[Perf] Linux/x64: 1 Regression on 6/22/2026 5:32:56 PM +00:00

### Run Information

Name | Value
-- | --
Architecture | x64
OS | ubuntu 22.04
Queue | ViperUbuntu
Baseline | [b4ca93f1d026919b29a1000cf520db442cabf61b](https://github.com/dotnet/runtime/commit/b4ca93f1d026919b29a1000cf520db442cabf61b)
Compare | [2fb056790aea48d9d94e221309c506b2a2506849](https://github.com/dotnet/runtime/commit/2fb056790aea48d9d94e221309c506b2a2506849)
Diff | [Diff](https://github.com/dotnet/runtime/compare/b4ca93f1d026919b29a1000cf520db442cabf61b...2fb056790aea48d9d94e221309c506b2a2506849)
Configs | AOT:true, CompilationMode:wasm, RunKind:micro

### Regressions in System.Collections.CtorGivenSize<Int32>

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

• [Dictionary - 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.CtorGivenSize*'
```

### System.Collections.CtorGivenSize<Int32>.Dictionary(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/Create/CtorGivenSize.cs and reproduce System.Collections.CtorGivenSize with the documented benchmarks_ci.py command. Compare the baseline and test commits, then inspect the linked test report and history graph. Done means identifying the cause of the Dictionary(Size: 512) slowdown and verifying the result against the reported baseline.

Written by the indexing model from the issue text.