[Perf] Windows/x86: 8 Regressions on 2/5/2026 9:06:10 PM +00:00

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#68,634 opened on Feb 10, 2026 1 comment 0 reactions 0 assignees View on GitHub

arch-x86 branch-refs/heads/main kind-micro os-windows perf-regression PGO runtime-coreclr untriaged

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Forks: 8
PR merge metrics: PR metrics pending

Description

### Run Information

Name | Value
-- | --
Architecture | x86
OS | Windows 10.0.22631
Queue | ViperWindows
Baseline | [f6b4b6ce93a8dce234a93e461060c648865dae3f](https://github.com/dotnet/runtime/commit/f6b4b6ce93a8dce234a93e461060c648865dae3f)
Compare | [a1bbba5d0ad98e82596ac3469e4534ae7966ed6f](https://github.com/dotnet/runtime/commit/a1bbba5d0ad98e82596ac3469e4534ae7966ed6f)
Diff | [Diff](https://github.com/dotnet/runtime/compare/f6b4b6ce93a8dce234a93e461060c648865dae3f...a1bbba5d0ad98e82596ac3469e4534ae7966ed6f)
Configs | CompilationMode:tiered, RunKind:micro

### Regressions in System.Collections.IndexerSet<Int32>

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

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

| 8.33 μs | 9.13 μs | 1.10 | 0.09 | False | | |

[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.IndexerSet*'
```

### System.Collections.IndexerSet<Int32>.ConcurrentDictionary(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

### Regressions in System.Threading.Channels.Tests.SpscUnboundedChannelPerfTests

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

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

| 43.32 ns | 47.36 ns | 1.09 | 0.28 | False | | |
|

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

| 15.51 ns | 16.88 ns | 1.09 | 0.09 | False | | |

[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.Threading.Channels.Tests.SpscUnboundedChannelPerfTests*'
```

### System.Threading.Channels.Tests.SpscUnboundedChannelPerfTests.ReadAsyncThenWriteAsync

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Threading.Channels.Tests.SpscUnboundedChannelPerfTests.TryWriteThenTryRead

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

### Regressions in System.Collections.IterateForEach<Int32>

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

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

| 152.85 ns | 282.64 ns | 1.85 | 0.09 | False | | |

[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<Int32>.FrozenDictionary(Size: 512)

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

### Regressions in System.MathBenchmarks.Double

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

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

| 151.53 μs | 160.19 μs | 1.06 | 0.02 | False | | |
|

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

| 197.90 μs | 215.82 μs | 1.09 | 0.06 | False | | |
|

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

| 191.63 μs | 212.83 μs | 1.11 | 0.04 | False | | |

[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.MathBenchmarks.Double*'
```

### System.MathBenchmarks.Double.Atanh

#### ETL Files

#### Histogram

#### JIT Disasms

### System.MathBenchmarks.Double.Asinh

#### ETL Files

#### Histogram

#### JIT Disasms

### System.MathBenchmarks.Double.Acosh

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

### Regressions in System.Tests.Perf_GC<Byte>

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

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

| 46.55 ns | 50.97 ns | 1.09 | 0.06 | False | | |

[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.Tests.Perf_GC*'
```

### System.Tests.Perf_GC<Byte>.AllocateArray(length: 1000, pinned: False)

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

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[Perf] Windows/x86: 8 Regressions on 2/5/2026 9:06:10 PM +00:00

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