[Perf] Linux/x64: 2 Regressions on 7/19/2026 12:47:15 AM +00:00

### Run Information

Name | Value
-- | --
Architecture | x64
OS | ubuntu 22.04
Queue | ViperUbuntu
Baseline | [7ee2d1104f4b95e23f38495bd94a8732252b401f](https://github.com/dotnet/runtime/commit/7ee2d1104f4b95e23f38495bd94a8732252b401f)
Compare | [cb84c8521ce6a4cbde63cb1a700fcb850be791ae](https://github.com/dotnet/runtime/commit/cb84c8521ce6a4cbde63cb1a700fcb850be791ae)
Diff | [Diff](https://github.com/dotnet/runtime/compare/7ee2d1104f4b95e23f38495bd94a8732252b401f...cb84c8521ce6a4cbde63cb1a700fcb850be791ae)
Configs | CompilationMode:wasm, RunKind:micro, RuntimeType:coreclr

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

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

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

| 534.71 μs | 987.71 μs | 1.85 | 0.33 | 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.CreateAddAndClear*'
```

### System.Collections.CreateAddAndClear<String>.ICollection(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 | [7ee2d1104f4b95e23f38495bd94a8732252b401f](https://github.com/dotnet/runtime/commit/7ee2d1104f4b95e23f38495bd94a8732252b401f)
Compare | [cb84c8521ce6a4cbde63cb1a700fcb850be791ae](https://github.com/dotnet/runtime/commit/cb84c8521ce6a4cbde63cb1a700fcb850be791ae)
Diff | [Diff](https://github.com/dotnet/runtime/compare/7ee2d1104f4b95e23f38495bd94a8732252b401f...cb84c8521ce6a4cbde63cb1a700fcb850be791ae)
Configs | CompilationMode:wasm, RunKind:micro, RuntimeType:coreclr

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

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

• [OrderedDictionary - Duration of single invocation]()
• [ADX - Test Multi Config Graph]()

| 1.99 ms | 2.41 ms | 1.21 | 0.40 | 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.CtorFromCollection*'
```

### System.Collections.CtorFromCollection<String>.OrderedDictionary(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 src/benchmarks/micro/libraries/System.Collections/CreateAddAndClear.cs and the System.Collections.CtorFromCollection benchmark, then run scripts/benchmarks_ci.py using the filters in the issue. Compare the reported baseline and test results and use the linked profiling and benchmarking workflow docs. Done means identifying and correcting the cause of both Linux/x64 WebAssembly regressions, with benchmark results showing they no longer regress.

Written by the indexing model from the issue text.