dotnet / dotnet/perf-autofiling-issues

[Perf] Windows/x86: 9 Regressions on 6/23/2026 12:06:09 PM +00:00

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

### Run Information

Name | Value
-- | --
Architecture | x86
OS | Windows 10.0.22631
Queue | ViperWindows
Baseline | [59979e6401af21c7cdf4f61fb35ea3568cb93e5d](https://github.com/dotnet/runtime/commit/59979e6401af21c7cdf4f61fb35ea3568cb93e5d)
Compare | [f4430a4ba762ef82841ff7a8c340ed8854b2bca9](https://github.com/dotnet/runtime/commit/f4430a4ba762ef82841ff7a8c340ed8854b2bca9)
Diff | [Diff](https://github.com/dotnet/runtime/compare/59979e6401af21c7cdf4f61fb35ea3568cb93e5d...f4430a4ba762ef82841ff7a8c340ed8854b2bca9)
Configs | CompilationMode:tiered, RunKind:micro

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

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

  • [WriteAsync - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 2.39 ms | 3.79 ms | 1.58 | 0.65 | False | | |
|
  • [ReadScatterAsync - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 720.44 μs | 913.12 μs | 1.27 | 0.44 | False | | |
|
  • [WriteGatherAsync - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 1.11 ms | 1.31 ms | 1.19 | 0.56 | False | | |
|
  • [WriteAsync - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 4.62 ms | 5.29 ms | 1.14 | 0.55 | 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.IO.Tests.Perf_RandomAccess*'
```

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

#### ETL Files

#### Histogram

#### JIT Disasms

### System.IO.Tests.Perf_RandomAccess.ReadScatterAsync(fileSize: 1048576, buffersSize: 16384, options: None)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.IO.Tests.Perf_RandomAccess.WriteGatherAsync(fileSize: 1048576, buffersSize: 16384, options: None)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.IO.Tests.Perf_RandomAccess.WriteAsync(fileSize: 1048576, bufferSize: 4096, options: Asynchronous)

#### 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 | [59979e6401af21c7cdf4f61fb35ea3568cb93e5d](https://github.com/dotnet/runtime/commit/59979e6401af21c7cdf4f61fb35ea3568cb93e5d)
Compare | [f4430a4ba762ef82841ff7a8c340ed8854b2bca9](https://github.com/dotnet/runtime/commit/f4430a4ba762ef82841ff7a8c340ed8854b2bca9)
Diff | [Diff](https://github.com/dotnet/runtime/compare/59979e6401af21c7cdf4f61fb35ea3568cb93e5d...f4430a4ba762ef82841ff7a8c340ed8854b2bca9)
Configs | CompilationMode:tiered, RunKind:micro

### Regressions in System.IO.Tests.Perf_File

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

  • [ReadAllBytesAsync - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 28.54 μs | 33.10 μs | 1.16 | 0.44 | 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_File*'
```

### System.IO.Tests.Perf_File.ReadAllBytesAsync(size: 4096)

#### 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 | [59979e6401af21c7cdf4f61fb35ea3568cb93e5d](https://github.com/dotnet/runtime/commit/59979e6401af21c7cdf4f61fb35ea3568cb93e5d)
Compare | [f4430a4ba762ef82841ff7a8c340ed8854b2bca9](https://github.com/dotnet/runtime/commit/f4430a4ba762ef82841ff7a8c340ed8854b2bca9)
Diff | [Diff](https://github.com/dotnet/runtime/compare/59979e6401af21c7cdf4f61fb35ea3568cb93e5d...f4430a4ba762ef82841ff7a8c340ed8854b2bca9)
Configs | CompilationMode:tiered, RunKind:micro

### Regressions in System.Text.RegularExpressions.Tests.Perf_Regex_Cache

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

  • [IsMatch - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 49.75 ms | 178.36 ms | 3.59 | 0.78 | 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.RegularExpressions.Tests.Perf_Regex_Cache*'
```

### System.Text.RegularExpressions.Tests.Perf_Regex_Cache.IsMatch(total: 400000, unique: 7, cacheSize: 15)

#### 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 | [06b80b7dccace56abf56e91e72ee26c2a682b76e](https://github.com/dotnet/runtime/commit/06b80b7dccace56abf56e91e72ee26c2a682b76e)
Compare | [f4430a4ba762ef82841ff7a8c340ed8854b2bca9](https://github.com/dotnet/runtime/commit/f4430a4ba762ef82841ff7a8c340ed8854b2bca9)
Diff | [Diff](https://github.com/dotnet/runtime/compare/06b80b7dccace56abf56e91e72ee26c2a682b76e...f4430a4ba762ef82841ff7a8c340ed8854b2bca9)
Configs | CompilationMode:tiered, RunKind:micro

### Regressions in System.Net.Http.Tests.SocketsHttpHandlerPerfTest

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

  • [Get - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 44.18 μs | 50.59 μs | 1.15 | 0.44 | 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.Net.Http.Tests.SocketsHttpHandlerPerfTest*'
```

### System.Net.Http.Tests.SocketsHttpHandlerPerfTest.Get(ssl: True, chunkedResponse: True, responseLength: 1)

#### 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 | [59979e6401af21c7cdf4f61fb35ea3568cb93e5d](https://github.com/dotnet/runtime/commit/59979e6401af21c7cdf4f61fb35ea3568cb93e5d)
Compare | [f4430a4ba762ef82841ff7a8c340ed8854b2bca9](https://github.com/dotnet/runtime/commit/f4430a4ba762ef82841ff7a8c340ed8854b2bca9)
Diff | [Diff](https://github.com/dotnet/runtime/compare/59979e6401af21c7cdf4f61fb35ea3568cb93e5d...f4430a4ba762ef82841ff7a8c340ed8854b2bca9)
Configs | CompilationMode:tiered, RunKind:micro

### 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]()
| 6.88 μs | 13.38 μs | 1.94 | 0.68 | 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

[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 | [59979e6401af21c7cdf4f61fb35ea3568cb93e5d](https://github.com/dotnet/runtime/commit/59979e6401af21c7cdf4f61fb35ea3568cb93e5d)
Compare | [0d1a20fb14109f277df06ebee3f83c964f9dcc61](https://github.com/dotnet/runtime/commit/0d1a20fb14109f277df06ebee3f83c964f9dcc61)
Diff | [Diff](https://github.com/dotnet/runtime/compare/59979e6401af21c7cdf4f61fb35ea3568cb93e5d...0d1a20fb14109f277df06ebee3f83c964f9dcc61)
Configs | CompilationMode:tiered, RunKind:micro

### 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]()
| 1.34 μs | 1.73 μs | 1.30 | 0.48 | 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.Buffers.Tests.RentReturnArrayPoolTests*'
```

### System.Buffers.Tests.RentReturnArrayPoolTests<Object>.ProducerConsumer(RentalSize: 4096, ManipulateArray: True, Async: False, UseSharedPool: 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 benchmark sources performance/src/benchmarks/micro/libraries/System.IO.FileSystem/Perf.RandomAccess.cs and Perf.File.cs, then run the provided benchmarks_ci.py commands on Windows x86. Compare the results with the listed baseline and compare commits to identify the cause of the reported regressions. Done means the affected benchmarks no longer reproduce the regression and the performance report is validated.

Written by the indexing model from the issue text.

Assessment

Tech stack
csharp
Domain
performance
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Quiet
Clarity
Needs clarification
Newbie friendliness
35/100

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