dotnet / dotnet/perf-autofiling-issues

[Perf] Windows/x86: 6 Regressions on 7/20/2026 2:22:01 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 | [f43516f45fff5920eabd11753bd5f1803cfacd0c](https://github.com/dotnet/runtime/commit/f43516f45fff5920eabd11753bd5f1803cfacd0c)
Compare | [73a9e0a51ed85481b7f03ca3f2696e020365afd6](https://github.com/dotnet/runtime/commit/73a9e0a51ed85481b7f03ca3f2696e020365afd6)
Diff | [Diff](https://github.com/dotnet/runtime/compare/f43516f45fff5920eabd11753bd5f1803cfacd0c...73a9e0a51ed85481b7f03ca3f2696e020365afd6)
Configs | CompilationMode:tiered, RunKind:micro

### Regressions in System.Linq.Tests.Perf_Enumerable

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

  • [FirstWithPredicate_LastElementMatches - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 496.98 ns | 587.25 ns | 1.18 | 0.31 | False | | |
|
  • [Sum - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 363.26 ns | 423.03 ns | 1.16 | 0.53 | 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.Linq.Tests.Perf_Enumerable*'
```

### System.Linq.Tests.Perf_Enumerable.FirstWithPredicate_LastElementMatches(input: IEnumerable)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Linq.Tests.Perf_Enumerable.Sum(input: IEnumerable)

#### 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 | [563abf220847ed66cab58f0d7d166cb264874f40](https://github.com/dotnet/runtime/commit/563abf220847ed66cab58f0d7d166cb264874f40)
Compare | [73a9e0a51ed85481b7f03ca3f2696e020365afd6](https://github.com/dotnet/runtime/commit/73a9e0a51ed85481b7f03ca3f2696e020365afd6)
Diff | [Diff](https://github.com/dotnet/runtime/compare/563abf220847ed66cab58f0d7d166cb264874f40...73a9e0a51ed85481b7f03ca3f2696e020365afd6)
Configs | CompilationMode:tiered, RunKind:micro

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

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

  • [LinkedList - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 6.25 μs | 6.74 μs | 1.08 | 0.21 | 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.Collections.CtorFromCollection*'
```

### System.Collections.CtorFromCollection<Int32>.LinkedList(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 | [563abf220847ed66cab58f0d7d166cb264874f40](https://github.com/dotnet/runtime/commit/563abf220847ed66cab58f0d7d166cb264874f40)
Compare | [73a9e0a51ed85481b7f03ca3f2696e020365afd6](https://github.com/dotnet/runtime/commit/73a9e0a51ed85481b7f03ca3f2696e020365afd6)
Diff | [Diff](https://github.com/dotnet/runtime/compare/563abf220847ed66cab58f0d7d166cb264874f40...73a9e0a51ed85481b7f03ca3f2696e020365afd6)
Configs | CompilationMode:tiered, RunKind:micro

### Regressions in System.Tests.Perf_String

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

  • [IndexerCheckPathLength - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 98.25 ns | 117.19 ns | 1.19 | 0.17 | 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.Tests.Perf_String*'
```

### System.Tests.Perf_String.IndexerCheckPathLength

#### 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 | [563abf220847ed66cab58f0d7d166cb264874f40](https://github.com/dotnet/runtime/commit/563abf220847ed66cab58f0d7d166cb264874f40)
Compare | [73a9e0a51ed85481b7f03ca3f2696e020365afd6](https://github.com/dotnet/runtime/commit/73a9e0a51ed85481b7f03ca3f2696e020365afd6)
Diff | [Diff](https://github.com/dotnet/runtime/compare/563abf220847ed66cab58f0d7d166cb264874f40...73a9e0a51ed85481b7f03ca3f2696e020365afd6)
Configs | CompilationMode:tiered, RunKind:micro

### Regressions in System.Numerics.Tests.Perf_VectorConvert

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

  • [Convert_double_long - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 502.10 ns | 548.45 ns | 1.09 | 0.08 | 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.Numerics.Tests.Perf_VectorConvert*'
```

### System.Numerics.Tests.Perf_VectorConvert.Convert_double_long

#### 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 | [563abf220847ed66cab58f0d7d166cb264874f40](https://github.com/dotnet/runtime/commit/563abf220847ed66cab58f0d7d166cb264874f40)
Compare | [73a9e0a51ed85481b7f03ca3f2696e020365afd6](https://github.com/dotnet/runtime/commit/73a9e0a51ed85481b7f03ca3f2696e020365afd6)
Diff | [Diff](https://github.com/dotnet/runtime/compare/563abf220847ed66cab58f0d7d166cb264874f40...73a9e0a51ed85481b7f03ca3f2696e020365afd6)
Configs | CompilationMode:tiered, RunKind:micro

### Regressions in System.Numerics.Tests.Perf_BigInteger

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

  • [Parse - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 135.05 ns | 163.41 ns | 1.21 | 0.04 | 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.Numerics.Tests.Perf_BigInteger*'
```

### System.Numerics.Tests.Perf_BigInteger.Parse(numberString: -2147483648)

#### 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 by running the benchmark commands in the Repro sections against the listed x86 Windows configuration, then compare the baseline and test commits. Inspect the named sources in src/benchmarks/micro/libraries/System.Linq/Perf.Enumerable.cs, System.Collections/Create/CtorFromCollection.cs, and System.Runtime/Perf.String.cs. Done means confirming the regressions and identifying the responsible change or required follow-up.

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
Quiet
Clarity
Needs clarification
Newbie friendliness
45/100

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