[Perf] Linux/x64: 2 Improvements on 8/3/2026 7:26:34 AM +00:00

### Run Information

Name | Value
-- | --
Architecture | x64
OS | ubuntu 22.04
Queue | ViperUbuntu
Baseline | [79efd2de59f086171fd811d7375241616c43b890](https://github.com/dotnet/runtime/commit/79efd2de59f086171fd811d7375241616c43b890)
Compare | [c4fc2a5afc5644e10973054b1aa63c27a1584404](https://github.com/dotnet/runtime/commit/c4fc2a5afc5644e10973054b1aa63c27a1584404)
Diff | [Diff](https://github.com/dotnet/runtime/compare/79efd2de59f086171fd811d7375241616c43b890...c4fc2a5afc5644e10973054b1aa63c27a1584404)
Configs | CompilationMode:wasm, RunKind:micro, RuntimeType:coreclr

### Improvements in System.Collections.CtorDefaultSizeNonGeneric

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

• [ArrayList - Duration of single invocation]()
• 📝 - [Benchmark Source]()
• [ADX - Test Multi Config Graph]()

| 220.52 ns | 208.07 ns | 0.94 | 0.16 | False | | |

![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.CtorDefaultSizeNonGeneric*'
```

### System.Collections.CtorDefaultSizeNonGeneric.ArrayList

#### 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)

---

### Run Information

Name | Value
-- | --
Architecture | x64
OS | ubuntu 22.04
Queue | ViperUbuntu
Baseline | [79efd2de59f086171fd811d7375241616c43b890](https://github.com/dotnet/runtime/commit/79efd2de59f086171fd811d7375241616c43b890)
Compare | [c4fc2a5afc5644e10973054b1aa63c27a1584404](https://github.com/dotnet/runtime/commit/c4fc2a5afc5644e10973054b1aa63c27a1584404)
Diff | [Diff](https://github.com/dotnet/runtime/compare/79efd2de59f086171fd811d7375241616c43b890...c4fc2a5afc5644e10973054b1aa63c27a1584404)
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
-- | -- | -- | -- | -- | -- | -- | -- | --
|

• [SortedSet - Duration of single invocation]()
• 📝 - [Benchmark Source]()
• [ADX - Test Multi Config Graph]()

| 194.38 ns | 177.80 ns | 0.91 | 0.17 | False | | |

![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>.SortedSet

#### 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 sources src/benchmarks/micro/libraries/System.Collections/Create/CtorDefaultSizeNonGeneric.cs and CtorDefaultSize.cs, then run the listed benchmarks with scripts/benchmarks_ci.py. Review the linked test reports and compare the baseline and test results. Done means confirming whether the reported improvements are expected and determining whether a runtime change is needed.

Written by the indexing model from the issue text.