[Perf] Windows/x86: 2 Regressions on 7/19/2026 9:20:49 AM +00:00

### Run Information

Name | Value
-- | --
Architecture | x86
OS | Windows 10.0.22631
Queue | ViperWindows
Baseline | [13c03a4a9a854291f77636b1e15038e65919e68b](https://github.com/dotnet/runtime/commit/13c03a4a9a854291f77636b1e15038e65919e68b)
Compare | [c536338d89a6ccc0bcbca46e44e3343d990e06aa](https://github.com/dotnet/runtime/commit/c536338d89a6ccc0bcbca46e44e3343d990e06aa)
Diff | [Diff](https://github.com/dotnet/runtime/compare/13c03a4a9a854291f77636b1e15038e65919e68b...c536338d89a6ccc0bcbca46e44e3343d990e06aa)
Configs | CompilationMode:tiered, RunKind:micro

### Regressions in System.Collections.IterateForEach<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]()

| 1.95 μs | 2.23 μs | 1.14 | 0.26 | False | | |
|

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

| 1.40 μs | 1.54 μs | 1.10 | 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
py .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Collections.IterateForEach*'
```

### System.Collections.IterateForEach<String>.OrderedDictionary(Size: 512)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Collections.IterateForEach<String>.Queue(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 regression report and the benchmark source at src/benchmarks/micro/libraries/System.Collections/Iterate/IterateForEach.cs#L159-L167, then run the provided benchmarks_ci.py command for System.Collections.IterateForEach. Compare the baseline and test commits and use the linked history, reports, and profiling workflow to identify the regression; done means the cause is addressed and the OrderedDictionary and Queue benchmarks no longer regress.

Written by the indexing model from the issue text.