[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 benchmark sources at src/benchmarks/micro/libraries/System.Collections/CreateAddAndRemove.cs and src/benchmarks/micro/runtime/Benchstones/BenchF/LLoops.cs, then read the benchmarking workflow linked in the issue. Reproduce both filters with scripts/benchmarks_ci.py and compare the baseline and compare commits using the linked reports. Done means the cause and appropriate resolution are established for both regressions.

Written by the indexing model from the issue text.