[Perf] Linux/x64: 2 Regressions on 6/25/2026 4:49:37 AM +00:00

### Run Information

Name | Value
-- | --
Architecture | x64
OS | ubuntu 22.04
Queue | ViperUbuntu
Baseline | [ce71db3201f610d5a8cbf692cc3081f8784992fc](https://github.com/dotnet/runtime/commit/ce71db3201f610d5a8cbf692cc3081f8784992fc)
Compare | [42f3669b3a7f418f571ad63a77b3e7ebf9ee64a8](https://github.com/dotnet/runtime/commit/42f3669b3a7f418f571ad63a77b3e7ebf9ee64a8)
Diff | [Diff](https://github.com/dotnet/runtime/compare/ce71db3201f610d5a8cbf692cc3081f8784992fc...42f3669b3a7f418f571ad63a77b3e7ebf9ee64a8)
Configs | CompilationMode:wasm, RunKind:micro, RuntimeType:coreclr

### Regressions in System.Collections.CreateAddAndRemove<String>

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

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

| 33.18 ms | 41.48 ms | 1.25 | 0.36 | 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.CreateAddAndRemove*'
```

### System.Collections.CreateAddAndRemove<String>.SortedList(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)

---

### Run Information

Name | Value
-- | --
Architecture | x64
OS | ubuntu 22.04
Queue | ViperUbuntu
Baseline | [ce71db3201f610d5a8cbf692cc3081f8784992fc](https://github.com/dotnet/runtime/commit/ce71db3201f610d5a8cbf692cc3081f8784992fc)
Compare | [42f3669b3a7f418f571ad63a77b3e7ebf9ee64a8](https://github.com/dotnet/runtime/commit/42f3669b3a7f418f571ad63a77b3e7ebf9ee64a8)
Diff | [Diff](https://github.com/dotnet/runtime/compare/ce71db3201f610d5a8cbf692cc3081f8784992fc...42f3669b3a7f418f571ad63a77b3e7ebf9ee64a8)
Configs | CompilationMode:wasm, RunKind:micro, RuntimeType:coreclr

### Regressions in Benchstone.BenchF.LLoops

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

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

| 19.31 secs | 20.96 secs | 1.09 | 0.22 | 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 'Benchstone.BenchF.LLoops*'
```

### Benchstone.BenchF.LLoops.Test

#### 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 two benchmark sources, src/benchmarks/micro/libraries/System.Collections/CreateAddAndRemove.cs and src/benchmarks/micro/runtime/Benchstones/BenchF/LLoops.cs, then run the provided benchmarks_ci.py commands. Compare the baseline and test reports and the linked commit diff to determine whether the regressions reproduce. Done should be a documented explanation with an appropriate fix or triage decision.

Written by the indexing model from the issue text.