[Perf] Windows/x86: 16 Regressions on 6/2/2026 4:02:46 PM +00:00

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#74,247 opened on Jun 9, 2026 0 comments 0 reactions 0 assignees View on GitHub

arch-x86 branch-refs/heads/main compilationmode-tiered kind-micro os-windows perf-regression runkind-micro 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 | [3472dd55e0b00e5689992068d720ad32fe6df377](https://github.com/dotnet/runtime/commit/3472dd55e0b00e5689992068d720ad32fe6df377)
Compare | [05af41550d4c764284d03bb8d79a977c5cacba8d](https://github.com/dotnet/runtime/commit/05af41550d4c764284d03bb8d79a977c5cacba8d)
Diff | [Diff](https://github.com/dotnet/runtime/compare/3472dd55e0b00e5689992068d720ad32fe6df377...05af41550d4c764284d03bb8d79a977c5cacba8d)
Configs | CompilationMode:tiered, RunKind:micro

### Regressions in System.Collections.Perf_LengthBucketsFrozenDictionary

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

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

| 41.03 ns | 46.22 ns | 1.13 | 0.03 | False | | |
|

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

| 62.35 μs | 69.90 μs | 1.12 | 0.02 | False | | |
|

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

| 11.61 μs | 12.96 μs | 1.12 | 0.00 | False | | |
|

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

| 391.00 ns | 434.02 ns | 1.11 | 0.01 | False | | |
|

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

| 137.31 μs | 151.21 μs | 1.10 | 0.01 | False | | |
|

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

| 4.14 μs | 4.52 μs | 1.09 | 0.03 | False | | |
|

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

| 1.10 μs | 1.16 μs | 1.06 | 0.00 | False | | |

![graph]()
![graph]()
![graph]()
![graph]()
![graph]()
![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.Perf_LengthBucketsFrozenDictionary*'
```

### System.Collections.Perf_LengthBucketsFrozenDictionary.TryGetValue_True_FrozenDictionary(Count: 10, ItemsPerBucket: 1)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Collections.Perf_LengthBucketsFrozenDictionary.TryGetValue_True_FrozenDictionary(Count: 10000, ItemsPerBucket: 1)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Collections.Perf_LengthBucketsFrozenDictionary.TryGetValue_True_FrozenDictionary(Count: 1000, ItemsPerBucket: 5)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Collections.Perf_LengthBucketsFrozenDictionary.TryGetValue_True_FrozenDictionary(Count: 100, ItemsPerBucket: 1)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Collections.Perf_LengthBucketsFrozenDictionary.TryGetValue_True_FrozenDictionary(Count: 10000, ItemsPerBucket: 5)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Collections.Perf_LengthBucketsFrozenDictionary.TryGetValue_True_FrozenDictionary(Count: 1000, ItemsPerBucket: 1)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Collections.Perf_LengthBucketsFrozenDictionary.TryGetValue_True_FrozenDictionary(Count: 100, ItemsPerBucket: 5)

#### 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.Buffers.Tests.RentReturnArrayPoolTests<Object>

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

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

| 802.22 ns | 2042.42 ns | 2.55 | 0.91 | False | | |
|

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

| 1.42 μs | 3.09 μs | 2.18 | 0.59 | False | | |
|

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

| 1.34 μs | 1.51 μs | 1.13 | 0.32 | False | | |

![graph]()
![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.Buffers.Tests.RentReturnArrayPoolTests*'
```

### System.Buffers.Tests.RentReturnArrayPoolTests<Object>.ProducerConsumer(RentalSize: 4096, ManipulateArray: False, Async: False, UseSharedPool: True)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Buffers.Tests.RentReturnArrayPoolTests<Object>.ProducerConsumer(RentalSize: 4096, ManipulateArray: False, Async: True, UseSharedPool: False)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Buffers.Tests.RentReturnArrayPoolTests<Object>.ProducerConsumer(RentalSize: 4096, ManipulateArray: True, Async: False, UseSharedPool: False)

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

### Regressions in System.IO.Tests.Perf_FileStream

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

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

| 14.68 ms | 19.84 ms | 1.35 | 0.48 | False | | |
|

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

| 2.43 ms | 2.73 ms | 1.12 | 0.66 | 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.IO.Tests.Perf_FileStream*'
```

### System.IO.Tests.Perf_FileStream.FlushAsync(fileSize: 1024, options: Asynchronous)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.IO.Tests.Perf_FileStream.WriteAsync(fileSize: 1048576, userBufferSize: 4096, options: None)

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

### Regressions in System.IO.Tests.Perf_RandomAccess

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

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

| 1.14 ms | 1.76 ms | 1.55 | 0.51 | 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
py .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.IO.Tests.Perf_RandomAccess*'
```

### System.IO.Tests.Perf_RandomAccess.ReadAsync(fileSize: 1048576, bufferSize: 4096, options: None)

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

### Regressions in System.Threading.Tasks.ValueTaskPerfTest

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

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

| 1.84 μs | 5.87 μs | 3.19 | 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
py .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Threading.Tasks.ValueTaskPerfTest*'
```

### System.Threading.Tasks.ValueTaskPerfTest.CreateAndAwait_FromDelayedTCS

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

### Regressions in System.Threading.Tests.Perf_SemaphoreSlim

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

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

| 3.20 μs | 4.77 μs | 1.49 | 0.65 | 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
py .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Threading.Tests.Perf_SemaphoreSlim*'
```

### System.Threading.Tests.Perf_SemaphoreSlim.ReleaseWaitAsync_WithCancellationTokenAndTimeout

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

### Regressions in System.Text.Perf_Ascii

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

[FromUtf16 - Duration of single invocation]()
📝 - [Benchmark Source]()
[ADX - Test Multi Config Graph]()

| 13.06 ns | 19.41 ns | 1.49 | 0.65 | 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
py .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Text.Perf_Ascii*'
```

### System.Text.Perf_Ascii.FromUtf16(Size: 128)

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

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[Perf] Windows/x86: 16 Regressions on 6/2/2026 4:02:46 PM +00:00

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