[Perf] Windows/x86: 28 Regressions on 6/5/2026 2:49:34 AM +00:00

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#74,251 opened on Jun 9, 2026 2 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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Stars: 10
Forks: 8
PR merge metrics: PR metrics pending

Description

### Run Information

Name | Value
-- | --
Architecture | x86
OS | Windows 10.0.22631
Queue | ViperWindows
Baseline | [1c04596e61da849ad8f0fc008e88f000d509eee5](https://github.com/dotnet/runtime/commit/1c04596e61da849ad8f0fc008e88f000d509eee5)
Compare | [8df86ac78f1e4510c63880a6f93507af5fdd4ee4](https://github.com/dotnet/runtime/commit/8df86ac78f1e4510c63880a6f93507af5fdd4ee4)
Diff | [Diff](https://github.com/dotnet/runtime/compare/1c04596e61da849ad8f0fc008e88f000d509eee5...8df86ac78f1e4510c63880a6f93507af5fdd4ee4)
Configs | CompilationMode:tiered, RunKind:micro

### Regressions in System.Text.Json.Tests.Utf8JsonReaderCommentsTests

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

[Utf8JsonReaderCommentParsing - Duration of single invocation]()
📝 - [Benchmark Source]()
[ADX - Test Multi Config Graph]()

| 60.01 ns | 87.53 ns | 1.46 | 0.12 | False | | |
|

[Utf8JsonReaderCommentParsing - Duration of single invocation]()
📝 - [Benchmark Source]()
[ADX - Test Multi Config Graph]()

| 62.62 ns | 90.34 ns | 1.44 | 0.10 | False | | |
|

[Utf8JsonReaderCommentParsing - Duration of single invocation]()
📝 - [Benchmark Source]()
[ADX - Test Multi Config Graph]()

| 63.93 ns | 89.86 ns | 1.41 | 0.07 | False | | |
|

[Utf8JsonReaderCommentParsing - Duration of single invocation]()
📝 - [Benchmark Source]()
[ADX - Test Multi Config Graph]()

| 59.65 ns | 83.69 ns | 1.40 | 0.14 | False | | |
|

[Utf8JsonReaderCommentParsing - Duration of single invocation]()
📝 - [Benchmark Source]()
[ADX - Test Multi Config Graph]()

| 62.57 ns | 82.99 ns | 1.33 | 0.11 | False | | |
|

[Utf8JsonReaderCommentParsing - Duration of single invocation]()
📝 - [Benchmark Source]()
[ADX - Test Multi Config Graph]()

| 62.59 ns | 82.10 ns | 1.31 | 0.12 | False | | |
|

[Utf8JsonReaderCommentParsing - Duration of single invocation]()
📝 - [Benchmark Source]()
[ADX - Test Multi Config Graph]()

| 113.41 ns | 141.10 ns | 1.24 | 0.02 | False | | |
|

[Utf8JsonReaderCommentParsing - Duration of single invocation]()
📝 - [Benchmark Source]()
[ADX - Test Multi Config Graph]()

| 112.67 ns | 138.13 ns | 1.23 | 0.04 | False | | |

![graph]()
![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.Text.Json.Tests.Utf8JsonReaderCommentsTests*'
```

### System.Text.Json.Tests.Utf8JsonReaderCommentsTests.Utf8JsonReaderCommentParsing(CommentHandling: Allow, SegmentSize: 0, TestCase: ShortSingleLine)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Text.Json.Tests.Utf8JsonReaderCommentsTests.Utf8JsonReaderCommentParsing(CommentHandling: Skip, SegmentSize: 100, TestCase: ShortSingleLine)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Text.Json.Tests.Utf8JsonReaderCommentsTests.Utf8JsonReaderCommentParsing(CommentHandling: Allow, SegmentSize: 100, TestCase: ShortMultiLine)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Text.Json.Tests.Utf8JsonReaderCommentsTests.Utf8JsonReaderCommentParsing(CommentHandling: Allow, SegmentSize: 0, TestCase: ShortMultiLine)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Text.Json.Tests.Utf8JsonReaderCommentsTests.Utf8JsonReaderCommentParsing(CommentHandling: Skip, SegmentSize: 0, TestCase: ShortSingleLine)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Text.Json.Tests.Utf8JsonReaderCommentsTests.Utf8JsonReaderCommentParsing(CommentHandling: Skip, SegmentSize: 0, TestCase: ShortMultiLine)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Text.Json.Tests.Utf8JsonReaderCommentsTests.Utf8JsonReaderCommentParsing(CommentHandling: Allow, SegmentSize: 0, TestCase: LongSingleLine)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Text.Json.Tests.Utf8JsonReaderCommentsTests.Utf8JsonReaderCommentParsing(CommentHandling: Skip, SegmentSize: 0, TestCase: LongSingleLine)

#### 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 | x86
OS | Windows 10.0.22631
Queue | ViperWindows
Baseline | [4c16f5f5f54b01319ff2a276f1a10e635402c3ca](https://github.com/dotnet/runtime/commit/4c16f5f5f54b01319ff2a276f1a10e635402c3ca)
Compare | [8df86ac78f1e4510c63880a6f93507af5fdd4ee4](https://github.com/dotnet/runtime/commit/8df86ac78f1e4510c63880a6f93507af5fdd4ee4)
Diff | [Diff](https://github.com/dotnet/runtime/compare/4c16f5f5f54b01319ff2a276f1a10e635402c3ca...8df86ac78f1e4510c63880a6f93507af5fdd4ee4)
Configs | CompilationMode:tiered, RunKind:micro

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

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

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

| 382.23 ns | 839.61 ns | 2.20 | 0.00 | False | | |
|

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

| 385.01 ns | 840.78 ns | 2.18 | 0.00 | False | | |
|

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

| 384.70 ns | 839.11 ns | 2.18 | 0.06 | False | | |
|

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

| 386.90 ns | 843.67 ns | 2.18 | 0.00 | False | | |

![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.CopyTo*'
```

### System.Collections.CopyTo<String>.Span(Size: 2048)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Collections.CopyTo<String>.ReadOnlyMemory(Size: 2048)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Collections.CopyTo<String>.ImmutableArray(Size: 2048)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Collections.CopyTo<String>.Memory(Size: 2048)

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

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

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

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

| 175.42 ns | 286.25 ns | 1.63 | 0.02 | False | | |
|

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

| 187.01 ns | 303.74 ns | 1.62 | 0.01 | False | | |
|

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

| 188.85 ns | 300.69 ns | 1.59 | 0.03 | False | | |
|

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

| 186.71 ns | 296.38 ns | 1.59 | 0.04 | False | | |

![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.CtorFromCollection*'
```

### System.Collections.CtorFromCollection<String>.ImmutableArray(Size: 512)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Collections.CtorFromCollection<String>.Stack(Size: 512)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Collections.CtorFromCollection<String>.Queue(Size: 512)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Collections.CtorFromCollection<String>.List(Size: 512)

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

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

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

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

| 16.09 μs | 17.66 μs | 1.10 | 0.03 | False | | |
|

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

| 17.77 μs | 19.06 μs | 1.07 | 0.03 | 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>.ImmutableHashSet(Size: 512)

#### ETL Files

#### Histogram

#### JIT Disasms

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

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

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

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

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

| 33.67 μs | 60.85 μs | 1.81 | 0.02 | False | | |
|

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

| 361.05 μs | 413.91 μs | 1.15 | 0.05 | 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.CreateAddAndRemove*'
```

### System.Collections.CreateAddAndRemove<String>.List(Size: 512)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Collections.CreateAddAndRemove<String>.SortedList(Size: 512)

#### 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
-- | -- | -- | -- | -- | -- | -- | -- | --
|

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

| 9.07 μs | 14.62 μs | 1.61 | 0.04 | False | | |
|

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

| 8.05 μs | 12.26 μs | 1.52 | 0.04 | 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<Int32>.ImmutableDictionary(Size: 512)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Collections.IterateForEach<Int32>.ImmutableHashSet(Size: 512)

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

Name | Value
-- | --
Architecture | x86
OS | Windows 10.0.22631
Queue | ViperWindows
Baseline | [4c16f5f5f54b01319ff2a276f1a10e635402c3ca](https://github.com/dotnet/runtime/commit/4c16f5f5f54b01319ff2a276f1a10e635402c3ca)
Compare | [ecaa1c589257cd25a5034dffba8e2a8fea10470a](https://github.com/dotnet/runtime/commit/ecaa1c589257cd25a5034dffba8e2a8fea10470a)
Diff | [Diff](https://github.com/dotnet/runtime/compare/4c16f5f5f54b01319ff2a276f1a10e635402c3ca...ecaa1c589257cd25a5034dffba8e2a8fea10470a)
Configs | CompilationMode:tiered, RunKind:micro

### Regressions in MicroBenchmarks.Serializers.Json_FromStream<CollectionsOfPrimitives>

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

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

| 181.77 μs | 201.79 μs | 1.11 | 0.06 | False | | |
|

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

| 181.44 μs | 198.00 μs | 1.09 | 0.03 | 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 'MicroBenchmarks.Serializers.Json_FromStream*'
```

### MicroBenchmarks.Serializers.Json_FromStream<CollectionsOfPrimitives>.SystemTextJson_Reflection_

#### ETL Files

#### Histogram

#### JIT Disasms

### MicroBenchmarks.Serializers.Json_FromStream<CollectionsOfPrimitives>.SystemTextJson_SourceGen_

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

### Regressions in System.Text.Json.Serialization.Tests.ReadJson<Nullable<DateTimeOffset>>

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

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

| 138.53 ns | 155.40 ns | 1.12 | 0.10 | 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.Json.Serialization.Tests.ReadJson>*'
```

### System.Text.Json.Serialization.Tests.ReadJson<Nullable<DateTimeOffset>>.DeserializeFromReader(Mode: SourceGen)

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

### Regressions in System.Text.Json.Serialization.Tests.ReadJson<Int32>

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

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

| 85.94 ns | 108.04 ns | 1.26 | 0.10 | 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.Json.Serialization.Tests.ReadJson*'
```

### System.Text.Json.Serialization.Tests.ReadJson<Int32>.DeserializeFromReader(Mode: SourceGen)

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

### Regressions in Microsoft.Extensions.DependencyInjection.ScopeValidationOnBuild

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

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

| 16.20 μs | 18.53 μs | 1.14 | 0.02 | 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 'Microsoft.Extensions.DependencyInjection.ScopeValidationOnBuild*'
```

### Microsoft.Extensions.DependencyInjection.ScopeValidationOnBuild.ValidateOnBuild

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

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Assessment

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[Perf] Windows/x86: 28 Regressions on 6/5/2026 2:49:34 AM +00:00

Description

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