[Perf] Linux/x64: 2 Improvements on 8/7/2026 7:09:09 PM +00:00

### Run Information

Name | Value
-- | --
Architecture | x64
OS | ubuntu 22.04
Queue | ViperUbuntu
Baseline | [b7130aa5e416e88ac48fafe92bf56a9d64e13c97](https://github.com/dotnet/runtime/commit/b7130aa5e416e88ac48fafe92bf56a9d64e13c97)
Compare | [4c86c57ac3a6569063da4cb0a7245aadbc276f00](https://github.com/dotnet/runtime/commit/4c86c57ac3a6569063da4cb0a7245aadbc276f00)
Diff | [Diff](https://github.com/dotnet/runtime/compare/b7130aa5e416e88ac48fafe92bf56a9d64e13c97...4c86c57ac3a6569063da4cb0a7245aadbc276f00)
Configs | AOT:true, CompilationMode:wasm, RunKind:micro

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

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

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

| 899.50 ns | 794.98 ns | 0.88 | 0.05 | False | | |
|

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

| 674.33 μs | 617.45 μs | 0.92 | 0.10 | 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.CreateAddAndClear*'
```

### System.Collections.CreateAddAndClear<String>.Span(Size: 512)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Collections.CreateAddAndClear<String>.ImmutableSortedDictionary(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 reported benchmarks in performance/src/benchmarks/micro/libraries/System.Collections/CreateAddAndClear.cs, especially the Span and ImmutableSortedDictionary entries, then run the documented benchmarks_ci.py command. Compare the supplied baseline and test results and consult the linked benchmarking and profiling workflow docs. The issue does not define a requested code change, so completion would require identifying and documenting a concrete actionable outcome.

Written by the indexing model from the issue text.