dotnet / dotnet/perf-autofiling-issues

[Perf] Windows/x86: 34 Regressions on 9/3/2026 9:59:06 PM +00:00

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arch-x86 branch-refs/heads/main compilationmode-tiered kind-micro os-windows perf-regression runkind-micro runtime-coreclr untriaged
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Description

### Run Information

Name | Value
-- | --
Architecture | x86
OS | Windows 10.0.22631
Queue | ViperWindows
Baseline | [334cc5c43dfb4b6acab5052c15ee8b1631d069bc](https://github.com/dotnet/runtime/commit/334cc5c43dfb4b6acab5052c15ee8b1631d069bc)
Compare | [c3c1cc3201d8ce138c7657fe6639540893ae0d0a](https://github.com/dotnet/runtime/commit/c3c1cc3201d8ce138c7657fe6639540893ae0d0a)
Diff | [Diff](https://github.com/dotnet/runtime/compare/334cc5c43dfb4b6acab5052c15ee8b1631d069bc...c3c1cc3201d8ce138c7657fe6639540893ae0d0a)
Configs | CompilationMode:tiered, RunKind:micro

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

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

  • [SortedList - Duration of single invocation]()
  • πŸ“ - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 139.60 ns | 152.33 ns | 1.09 | 0.04 | False | | |
|
  • [HashSet - Duration of single invocation]()
  • πŸ“ - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 274.69 ns | 298.64 ns | 1.09 | 0.01 | False | | |
|
  • [Array - Duration of single invocation]()
  • πŸ“ - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 55.49 ns | 60.24 ns | 1.09 | 0.03 | False | | |
|
  • [OrderedDictionary - Duration of single invocation]()
  • [ADX - Test Multi Config Graph]()
| 338.42 ns | 366.63 ns | 1.08 | 0.02 | False | | |
|
  • [Queue - Duration of single invocation]()
  • πŸ“ - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 71.01 ns | 75.88 ns | 1.07 | 0.03 | False | | |
|
  • [Stack - Duration of single invocation]()
  • πŸ“ - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 71.69 ns | 76.02 ns | 1.06 | 0.02 | False | | |
|
  • [Dictionary - Duration of single invocation]()
  • πŸ“ - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 344.24 ns | 364.90 ns | 1.06 | 0.01 | 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.CtorGivenSize*'
```

### System.Collections.CtorGivenSize<Int32>.SortedList(Size: 512)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Collections.CtorGivenSize<Int32>.HashSet(Size: 512)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Collections.CtorGivenSize<Int32>.Array(Size: 512)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Collections.CtorGivenSize<Int32>.OrderedDictionary(Size: 512)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Collections.CtorGivenSize<Int32>.Queue(Size: 512)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Collections.CtorGivenSize<Int32>.Stack(Size: 512)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Collections.CtorGivenSize<Int32>.Dictionary(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 | x86
OS | Windows 10.0.22631
Queue | ViperWindows
Baseline | [334cc5c43dfb4b6acab5052c15ee8b1631d069bc](https://github.com/dotnet/runtime/commit/334cc5c43dfb4b6acab5052c15ee8b1631d069bc)
Compare | [c3c1cc3201d8ce138c7657fe6639540893ae0d0a](https://github.com/dotnet/runtime/commit/c3c1cc3201d8ce138c7657fe6639540893ae0d0a)
Diff | [Diff](https://github.com/dotnet/runtime/compare/334cc5c43dfb4b6acab5052c15ee8b1631d069bc...c3c1cc3201d8ce138c7657fe6639540893ae0d0a)
Configs | CompilationMode:tiered, RunKind:micro

### Regressions in System.Reflection.Attributes

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

  • [GetCustomAttributesMethodBaseHit - Duration of single invocation]()
  • πŸ“ - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 767.47 ns | 850.95 ns | 1.11 | 0.04 | False | | |
|
  • [GetCustomAttributesMethodOverrideMissInherit - Duration of single invocation]()
  • πŸ“ - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 782.94 ns | 861.12 ns | 1.10 | 0.11 | False | | |
|
  • [GetCustomAttributesClassHit - Duration of single invocation]()
  • πŸ“ - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 759.87 ns | 823.18 ns | 1.08 | 0.05 | False | | |
|
  • [GetCustomAttributesMethodOverrideMiss - Duration of single invocation]()
  • πŸ“ - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 781.70 ns | 843.19 ns | 1.08 | 0.05 | False | | |
|
  • [GetCustomAttributesMethodOverrideHit - Duration of single invocation]()
  • πŸ“ - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 799.39 ns | 858.03 ns | 1.07 | 0.05 | False | | |
|
  • [GetCustomAttributesMethodBaseHitInherit - Duration of single invocation]()
  • πŸ“ - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 795.17 ns | 838.36 ns | 1.05 | 0.09 | False | | |

![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.Reflection.Attributes*'
```

### System.Reflection.Attributes.GetCustomAttributesMethodBaseHit

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Reflection.Attributes.GetCustomAttributesMethodOverrideMissInherit

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Reflection.Attributes.GetCustomAttributesClassHit

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Reflection.Attributes.GetCustomAttributesMethodOverrideMiss

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Reflection.Attributes.GetCustomAttributesMethodOverrideHit

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Reflection.Attributes.GetCustomAttributesMethodBaseHitInherit

#### 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 | [334cc5c43dfb4b6acab5052c15ee8b1631d069bc](https://github.com/dotnet/runtime/commit/334cc5c43dfb4b6acab5052c15ee8b1631d069bc)
Compare | [c3c1cc3201d8ce138c7657fe6639540893ae0d0a](https://github.com/dotnet/runtime/commit/c3c1cc3201d8ce138c7657fe6639540893ae0d0a)
Diff | [Diff](https://github.com/dotnet/runtime/compare/334cc5c43dfb4b6acab5052c15ee8b1631d069bc...c3c1cc3201d8ce138c7657fe6639540893ae0d0a)
Configs | CompilationMode:tiered, RunKind:micro

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

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

  • [SortedList - Duration of single invocation]()
  • πŸ“ - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 145.40 ns | 163.32 ns | 1.12 | 0.03 | False | | |
|
  • [Array - Duration of single invocation]()
  • πŸ“ - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 55.73 ns | 60.39 ns | 1.08 | 0.03 | False | | |
|
  • [Dictionary - Duration of single invocation]()
  • πŸ“ - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 360.37 ns | 389.52 ns | 1.08 | 0.02 | False | | |
|
  • [HashSet - Duration of single invocation]()
  • πŸ“ - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 294.70 ns | 318.28 ns | 1.08 | 0.03 | False | | |
|
  • [Stack - Duration of single invocation]()
  • πŸ“ - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 73.37 ns | 78.61 ns | 1.07 | 0.02 | False | | |
|
  • [OrderedDictionary - Duration of single invocation]()
  • [ADX - Test Multi Config Graph]()
| 362.36 ns | 387.86 ns | 1.07 | 0.03 | False | | |

![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.CtorGivenSize*'
```

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

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Collections.CtorGivenSize<String>.Array(Size: 512)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Collections.CtorGivenSize<String>.Dictionary(Size: 512)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Collections.CtorGivenSize<String>.HashSet(Size: 512)

#### ETL Files

#### Histogram

#### JIT Disasms

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

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Collections.CtorGivenSize<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)

---

### Run Information

Name | Value
-- | --
Architecture | x86
OS | Windows 10.0.22631
Queue | ViperWindows
Baseline | [334cc5c43dfb4b6acab5052c15ee8b1631d069bc](https://github.com/dotnet/runtime/commit/334cc5c43dfb4b6acab5052c15ee8b1631d069bc)
Compare | [c3c1cc3201d8ce138c7657fe6639540893ae0d0a](https://github.com/dotnet/runtime/commit/c3c1cc3201d8ce138c7657fe6639540893ae0d0a)
Diff | [Diff](https://github.com/dotnet/runtime/compare/334cc5c43dfb4b6acab5052c15ee8b1631d069bc...c3c1cc3201d8ce138c7657fe6639540893ae0d0a)
Configs | CompilationMode:tiered, RunKind:micro

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

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

  • [NewOperator_Array - Duration of single invocation]()
  • πŸ“ - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 418.23 ns | 543.76 ns | 1.30 | 0.03 | False | | |
|
  • [AllocateUninitializedArray - Duration of single invocation]()
  • [ADX - Test Multi Config Graph]()
| 55.21 ns | 70.10 ns | 1.27 | 0.03 | False | | |
|
  • [AllocateArray - Duration of single invocation]()
  • [ADX - Test Multi Config Graph]()
| 79.44 ns | 91.72 ns | 1.15 | 0.02 | False | | |
|
  • [AllocateUninitializedArray - Duration of single invocation]()
  • [ADX - Test Multi Config Graph]()
| 187.94 ns | 206.73 ns | 1.10 | 0.04 | False | | |
|
  • [NewOperator_Array - Duration of single invocation]()
  • πŸ“ - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 54.03 ns | 58.82 ns | 1.09 | 0.03 | False | | |

![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.Tests.Perf_GC*'
```

### System.Tests.Perf_GC<Char>.NewOperator_Array(length: 10000)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Tests.Perf_GC<Char>.AllocateUninitializedArray(length: 1000, pinned: False)

#### ETL Files

#### Histogram

#### JIT Disasms

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

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Tests.Perf_GC<Char>.AllocateUninitializedArray(length: 10000, pinned: False)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Tests.Perf_GC<Char>.NewOperator_Array(length: 1000)

#### 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 | [334cc5c43dfb4b6acab5052c15ee8b1631d069bc](https://github.com/dotnet/runtime/commit/334cc5c43dfb4b6acab5052c15ee8b1631d069bc)
Compare | [c3c1cc3201d8ce138c7657fe6639540893ae0d0a](https://github.com/dotnet/runtime/commit/c3c1cc3201d8ce138c7657fe6639540893ae0d0a)
Diff | [Diff](https://github.com/dotnet/runtime/compare/334cc5c43dfb4b6acab5052c15ee8b1631d069bc...c3c1cc3201d8ce138c7657fe6639540893ae0d0a)
Configs | CompilationMode:tiered, RunKind:micro

### 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]()
| 248.03 ns | 315.85 ns | 1.27 | 0.03 | False | | |
|
  • [AllocateArray - Duration of single invocation]()
  • [ADX - Test Multi Config Graph]()
| 56.00 ns | 68.68 ns | 1.23 | 0.06 | False | | |
|
  • [AllocateUninitializedArray - Duration of single invocation]()
  • [ADX - Test Multi Config Graph]()
| 126.86 ns | 144.62 ns | 1.14 | 0.03 | False | | |
|
  • [AllocateUninitializedArray - Duration of single invocation]()
  • [ADX - Test Multi Config Graph]()
| 29.45 ns | 31.36 ns | 1.06 | 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.Tests.Perf_GC*'
```

### System.Tests.Perf_GC<Byte>.AllocateArray(length: 10000, pinned: False)

#### ETL Files

#### Histogram

#### JIT Disasms

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

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Tests.Perf_GC<Byte>.AllocateUninitializedArray(length: 10000, pinned: False)

#### ETL Files

#### Histogram

#### JIT Disasms

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

#### 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 | [334cc5c43dfb4b6acab5052c15ee8b1631d069bc](https://github.com/dotnet/runtime/commit/334cc5c43dfb4b6acab5052c15ee8b1631d069bc)
Compare | [c3c1cc3201d8ce138c7657fe6639540893ae0d0a](https://github.com/dotnet/runtime/commit/c3c1cc3201d8ce138c7657fe6639540893ae0d0a)
Diff | [Diff](https://github.com/dotnet/runtime/compare/334cc5c43dfb4b6acab5052c15ee8b1631d069bc...c3c1cc3201d8ce138c7657fe6639540893ae0d0a)
Configs | CompilationMode:tiered, RunKind:micro

### Regressions in System.Collections.CtorGivenSizeNonGeneric

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

  • [Stack - Duration of single invocation]()
  • πŸ“ - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 71.38 ns | 76.13 ns | 1.07 | 0.02 | False | | |
|
  • [ArrayList - Duration of single invocation]()
  • πŸ“ - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 72.85 ns | 77.13 ns | 1.06 | 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.CtorGivenSizeNonGeneric*'
```

### System.Collections.CtorGivenSizeNonGeneric.Stack(Size: 512)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Collections.CtorGivenSizeNonGeneric.ArrayList(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 | x86
OS | Windows 10.0.22631
Queue | ViperWindows
Baseline | [334cc5c43dfb4b6acab5052c15ee8b1631d069bc](https://github.com/dotnet/runtime/commit/334cc5c43dfb4b6acab5052c15ee8b1631d069bc)
Compare | [c3c1cc3201d8ce138c7657fe6639540893ae0d0a](https://github.com/dotnet/runtime/commit/c3c1cc3201d8ce138c7657fe6639540893ae0d0a)
Diff | [Diff](https://github.com/dotnet/runtime/compare/334cc5c43dfb4b6acab5052c15ee8b1631d069bc...c3c1cc3201d8ce138c7657fe6639540893ae0d0a)
Configs | CompilationMode:tiered, RunKind:micro

### Regressions in System.Collections.Tests.Perf_BitArray

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

  • [BitArrayIntArrayCtor - Duration of single invocation]()
  • πŸ“ - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 102.98 ns | 109.33 ns | 1.06 | 0.02 | False | | |
|
  • [BitArraySetLengthShrink - Duration of single invocation]()
  • πŸ“ - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 35.76 ns | 37.97 ns | 1.06 | 0.02 | 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.Tests.Perf_BitArray*'
```

### System.Collections.Tests.Perf_BitArray.BitArrayIntArrayCtor(Size: 512)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Collections.Tests.Perf_BitArray.BitArraySetLengthShrink(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)

Contributor guide

No contributing guide indexed for this repository

Research direction

Start with the linked baseline-to-compare commit diff and the benchmark source at src/benchmarks/micro/libraries/System.Collections/Create/CtorGivenSize.cs. Read docs/benchmarking-workflow-dotnet-runtime.md and use the provided Windows/x86 reproduction command, then review the linked test report. Done requires identifying and addressing the cause of the reported collection-constructor regressions, or documenting a validated triage result.

Written by the indexing model from the issue text.

Assessment

Domain
performance
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Active
Clarity
Needs clarification
Newbie friendliness
30/100

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