dotnet / dotnet/perf-autofiling-issues

[Perf] Linux/x64: 240 Regressions on 4/28/2026 1:30:15 PM +00:00

Open
#72,187 10 comments 0 reactions 0 assignees View on GitHub
arch-wasm arch-x64 branch-refs/heads/main compilationmode-wasm kind-micro os-linux perf-regression runkind-micro runtimetype-coreclr untriaged
Dominant language
No language data
Stars
10
Forks
8
PR metrics pending

Description

### Run Information

Name | Value
-- | --
Architecture | x64
OS | ubuntu 22.04
Queue | ViperUbuntu
Baseline | [3ac6e13b2780bbaf03c62488fced60b9a76e9782](https://github.com/dotnet/runtime/commit/3ac6e13b2780bbaf03c62488fced60b9a76e9782)
Compare | [1d02af45d41c1fefa5ec4c139295081092af0905](https://github.com/dotnet/runtime/commit/1d02af45d41c1fefa5ec4c139295081092af0905)
Diff | [Diff](https://github.com/dotnet/runtime/compare/3ac6e13b2780bbaf03c62488fced60b9a76e9782...1d02af45d41c1fefa5ec4c139295081092af0905)
Configs | CompilationMode:wasm, RunKind:micro, RuntimeType:coreclr

### Regressions in System.Memory.Span<Char>

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

  • [Reverse - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 589.34 ns | 788.51 ns | 1.34 | 0.32 | False | | |
|
  • [Clear - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 393.11 ns | 487.26 ns | 1.24 | 0.32 | False | | |
|
  • [StartsWith - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 18.39 μs | 21.92 μs | 1.19 | 0.33 | False | | |
|
  • [IndexOfValue - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 21.37 μs | 24.68 μs | 1.16 | 0.21 | False | | |
|
  • [CopyTo - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 2.86 μs | 3.29 μs | 1.15 | 0.42 | False | | |
|
  • [IndexOfValue - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 1.82 μs | 2.06 μs | 1.13 | 0.32 | False | | |
|
  • [SequenceCompareTo - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 783.61 ns | 883.06 ns | 1.13 | 0.34 | False | | |
|
  • [BinarySearch - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 925.11 ns | 1035.09 ns | 1.12 | 0.47 | False | | |
|
  • [BinarySearch - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 593.20 ns | 661.05 ns | 1.11 | 0.35 | False | | |
|
  • [LastIndexOfValue - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 128.18 μs | 140.81 μs | 1.10 | 0.34 | False | | |
|
  • [LastIndexOfValue - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 21.67 μs | 23.68 μs | 1.09 | 0.21 | False | | |
|
  • [IndexOfValue - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 677.11 ns | 739.41 ns | 1.09 | 0.29 | False | | |
|
  • [ToArray - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 898.63 ns | 950.50 ns | 1.06 | 0.26 | False | | |

![graph]()
![graph]()
![graph]()
![graph]()
![graph]()
![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
python3 .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Memory.Span*'
```

### System.Memory.Span<Char>.Reverse(Size: 4)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Memory.Span<Char>.Clear(Size: 33)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Memory.Span<Char>.StartsWith(Size: 512)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Memory.Span<Char>.IndexOfValue(Size: 512)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Memory.Span<Char>.CopyTo(Size: 512)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Memory.Span<Char>.IndexOfValue(Size: 33)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Memory.Span<Char>.SequenceCompareTo(Size: 4)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Memory.Span<Char>.BinarySearch(Size: 33)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Memory.Span<Char>.BinarySearch(Size: 4)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Memory.Span<Char>.LastIndexOfValue(Size: 3000)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Memory.Span<Char>.LastIndexOfValue(Size: 512)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Memory.Span<Char>.IndexOfValue(Size: 4)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Memory.Span<Char>.ToArray(Size: 4)

#### 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 | x64
OS | ubuntu 22.04
Queue | ViperUbuntu
Baseline | [3ac6e13b2780bbaf03c62488fced60b9a76e9782](https://github.com/dotnet/runtime/commit/3ac6e13b2780bbaf03c62488fced60b9a76e9782)
Compare | [1d02af45d41c1fefa5ec4c139295081092af0905](https://github.com/dotnet/runtime/commit/1d02af45d41c1fefa5ec4c139295081092af0905)
Diff | [Diff](https://github.com/dotnet/runtime/compare/3ac6e13b2780bbaf03c62488fced60b9a76e9782...1d02af45d41c1fefa5ec4c139295081092af0905)
Configs | CompilationMode:wasm, RunKind:micro, RuntimeType:coreclr

### Regressions in System.Memory.Span<Int32>

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

  • [StartsWith - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 871.66 ns | 1401.37 ns | 1.61 | 0.35 | False | | |
|
  • [LastIndexOfAnyValues - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 1.93 μs | 2.71 μs | 1.40 | 0.38 | False | | |
|
  • [IndexOfAnyThreeValues - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 655.73 ns | 875.24 ns | 1.33 | 0.44 | False | | |
|
  • [LastIndexOfValue - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 576.02 ns | 751.20 ns | 1.30 | 0.34 | False | | |
|
  • [LastIndexOfValue - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 1.73 μs | 2.21 μs | 1.28 | 0.38 | False | | |
|
  • [IndexOfValue - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 1.78 μs | 2.25 μs | 1.26 | 0.30 | False | | |
|
  • [Fill - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 369.47 ns | 455.37 ns | 1.23 | 0.48 | False | | |
|
  • [ToArray - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 949.70 ns | 1066.14 ns | 1.12 | 0.29 | False | | |
|
  • [CopyToSame - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 431.21 ns | 476.51 ns | 1.11 | 0.29 | False | | |
|
  • [LastIndexOfAnyValues - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 24.37 μs | 26.73 μs | 1.10 | 0.41 | False | | |
|
  • [Reverse - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 2.16 μs | 2.34 μs | 1.08 | 0.47 | False | | |

![graph]()
![graph]()
![graph]()
![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
python3 .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Memory.Span*'
```

### System.Memory.Span<Int32>.StartsWith(Size: 4)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Memory.Span<Int32>.LastIndexOfAnyValues(Size: 33)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Memory.Span<Int32>.IndexOfAnyThreeValues(Size: 4)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Memory.Span<Int32>.LastIndexOfValue(Size: 4)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Memory.Span<Int32>.LastIndexOfValue(Size: 33)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Memory.Span<Int32>.IndexOfValue(Size: 33)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Memory.Span<Int32>.Fill(Size: 4)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Memory.Span<Int32>.ToArray(Size: 33)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Memory.Span<Int32>.CopyToSame(Size: 3000)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Memory.Span<Int32>.LastIndexOfAnyValues(Size: 512)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Memory.Span<Int32>.Reverse(Size: 33)

#### 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 | x64
OS | ubuntu 22.04
Queue | ViperUbuntu
Baseline | [3ac6e13b2780bbaf03c62488fced60b9a76e9782](https://github.com/dotnet/runtime/commit/3ac6e13b2780bbaf03c62488fced60b9a76e9782)
Compare | [1d02af45d41c1fefa5ec4c139295081092af0905](https://github.com/dotnet/runtime/commit/1d02af45d41c1fefa5ec4c139295081092af0905)
Diff | [Diff](https://github.com/dotnet/runtime/compare/3ac6e13b2780bbaf03c62488fced60b9a76e9782...1d02af45d41c1fefa5ec4c139295081092af0905)
Configs | CompilationMode:wasm, RunKind:micro, RuntimeType:coreclr

### Regressions in System.Globalization.Tests.StringSearch

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

  • [LastIndexOf_Word_NotFound - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 93.58 μs | 121.02 μs | 1.29 | 0.23 | False | | |
|
  • [LastIndexOf_Word_NotFound - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 20.15 μs | 24.61 μs | 1.22 | 0.24 | False | | |
|
  • [IndexOf_Word_NotFound - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 68.59 μs | 82.11 μs | 1.20 | 0.30 | False | | |
|
  • [IsSuffix_DifferentLastChar - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 27.13 μs | 32.41 μs | 1.19 | 0.25 | False | | |
|
  • [LastIndexOf_Word_NotFound - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 133.48 μs | 158.01 μs | 1.18 | 0.24 | False | | |
|
  • [LastIndexOf_Word_NotFound - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 111.97 μs | 130.04 μs | 1.16 | 0.25 | False | | |
|
  • [LastIndexOf_Word_NotFound - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 66.61 μs | 74.52 μs | 1.12 | 0.25 | False | | |
|
  • [IndexOf_Word_NotFound - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 19.97 μs | 22.27 μs | 1.12 | 0.26 | False | | |
|
  • [IsSuffix_SecondHalf - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 45.87 μs | 50.01 μs | 1.09 | 0.29 | False | | |
|
  • [IsSuffix_SecondHalf - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 44.87 μs | 48.82 μs | 1.09 | 0.28 | False | | |

![graph]()
![graph]()
![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
python3 .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Globalization.Tests.StringSearch*'
```

### System.Globalization.Tests.StringSearch.LastIndexOf_Word_NotFound(Options: (en-US, OrdinalIgnoreCase, False))

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Globalization.Tests.StringSearch.LastIndexOf_Word_NotFound(Options: (en-US, Ordinal, False))

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Globalization.Tests.StringSearch.IndexOf_Word_NotFound(Options: (, None, False))

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Globalization.Tests.StringSearch.IsSuffix_DifferentLastChar(Options: (en-US, OrdinalIgnoreCase, False))

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Globalization.Tests.StringSearch.LastIndexOf_Word_NotFound(Options: (, IgnoreCase, False))

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Globalization.Tests.StringSearch.LastIndexOf_Word_NotFound(Options: (en-US, IgnoreCase, True))

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Globalization.Tests.StringSearch.LastIndexOf_Word_NotFound(Options: (en-US, IgnoreNonSpace, False))

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Globalization.Tests.StringSearch.IndexOf_Word_NotFound(Options: (en-US, Ordinal, False))

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Globalization.Tests.StringSearch.IsSuffix_SecondHalf(Options: (, None, False))

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Globalization.Tests.StringSearch.IsSuffix_SecondHalf(Options: (en-US, None, 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)

Contributor guide

No contributing guide indexed for this repository

Research direction

Start with the linked System.Memory.Span benchmark source at src/benchmarks/micro/libraries/System.Memory/Span.cs and the generated regression reports. Compare the listed baseline commit with the compare commit and inspect the affected benchmark results. The issue does not define an acceptance criterion beyond the regression report, so confirm the expected resolution with maintainers.

Written by the indexing model from the issue text.

Assessment

Tech stack
linux, wasm
Domain
performance
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Quiet
Clarity
Needs clarification
Newbie friendliness
25/100

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.