[Perf] Linux/x64: 2 Improvements on 8/5/2026 1:23:13 AM +00:00

### Run Information

Name | Value
-- | --
Architecture | x64
OS | ubuntu 22.04
Queue | ViperUbuntu
Baseline | [ac85c6849c56dcb47e036b2a729c1e99dc413bab](https://github.com/dotnet/runtime/commit/ac85c6849c56dcb47e036b2a729c1e99dc413bab)
Compare | [c8f97975ab0d8ff84aebf176829e17f7c7052f03](https://github.com/dotnet/runtime/commit/c8f97975ab0d8ff84aebf176829e17f7c7052f03)
Diff | [Diff](https://github.com/dotnet/runtime/compare/ac85c6849c56dcb47e036b2a729c1e99dc413bab...c8f97975ab0d8ff84aebf176829e17f7c7052f03)
Configs | CompilationMode:wasm, RunKind:micro, RuntimeType:coreclr

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

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]()

| 242.01 ns | 225.86 ns | 0.93 | 0.19 | False | | |
|

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

| 240.27 ns | 224.97 ns | 0.94 | 0.21 | False | | |

![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<String>.SortedSet

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Collections.CtorDefaultSize<String>.Stack

#### 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/CtorDefaultSize.cs and the benchmarking workflow linked in the issue. Run the provided benchmarks_ci.py command, then compare the reported baseline and test results with the linked report. Done requires explaining whether the SortedSet and Stack improvement indicates an actionable runtime change; the issue does not specify a target fix.

Written by the indexing model from the issue text.