[Perf] Windows/x86: 9 Regressions on 1/24/2026 4:18:23 AM +00:00

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#68,322 opened on Feb 3, 2026 1 comment 0 reactions 0 assignees View on GitHub

arch-x86 branch-refs/heads/main kind-micro os-windows perf-regression 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 | [93c450ddc0b7d29b60e38b4c9c3bd1e43ec2eade](https://github.com/dotnet/runtime/commit/93c450ddc0b7d29b60e38b4c9c3bd1e43ec2eade)
Compare | [8fafcb3251a3d2ccde36612a2eab47e9ae8ebe2b](https://github.com/dotnet/runtime/commit/8fafcb3251a3d2ccde36612a2eab47e9ae8ebe2b)
Diff | [Diff](https://github.com/dotnet/runtime/compare/93c450ddc0b7d29b60e38b4c9c3bd1e43ec2eade...8fafcb3251a3d2ccde36612a2eab47e9ae8ebe2b)
Configs | CompilationMode:tiered, RunKind:micro

### Regressions in System.IO.Compression.Deflate

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

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

| 3.28 ms | 3.80 ms | 1.16 | 0.01 | False | | |

[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.Compression.Deflate*'
```

### System.IO.Compression.Deflate.Compress(level: Optimal, file: "TestDocument.pdf")

#### 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

### Regressions in System.Collections.IterateForEach<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]()

| 1.40 μs | 1.54 μs | 1.10 | 0.12 | False | | |

[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>.LinkedList(Size: 512)

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

### Regressions in System.Collections.Perf_DefaultFrozenDictionary

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

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

| 164.56 μs | 236.96 μs | 1.44 | 0.20 | False | | |

[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.Perf_DefaultFrozenDictionary*'
```

### System.Collections.Perf_DefaultFrozenDictionary.TryGetValue_True_FrozenDictionary(Count: 10000)

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

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

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

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

| 16.50 ns | 17.82 ns | 1.08 | 0.09 | False | | |

[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.Memory.Memory*'
```

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

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

### Regressions in System.IO.Compression.ZLib

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

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

| 3.35 ms | 3.76 ms | 1.13 | 0.01 | False | | |

[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.Compression.ZLib*'
```

### System.IO.Compression.ZLib.Compress(level: Optimal, file: "TestDocument.pdf")

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

### Regressions in System.Memory.Memory<Byte>

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

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

| 16.47 ns | 17.77 ns | 1.08 | 0.10 | False | | |

[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.Memory.Memory*'
```

### System.Memory.Memory<Byte>.Pin(Size: 512)

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

### Regressions in System.Text.Json.Serialization.Tests.ReadJson<ImmutableDictionary<String, String>>

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

[DeserializeFromUtf8Bytes - Duration of single invocation]()
📝 - [Benchmark Source]()
[ADX - Test Multi Config Graph]()

| 20.31 μs | 21.51 μs | 1.06 | 0.05 | False | | |

[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<ImmutableDictionary<String, String>>.DeserializeFromUtf8Bytes(Mode: SourceGen)

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

### Regressions in System.IO.Compression.Gzip

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

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

| 3.30 ms | 3.81 ms | 1.15 | 0.01 | False | | |

[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.Compression.Gzip*'
```

### System.IO.Compression.Gzip.Compress(level: Optimal, file: "TestDocument.pdf")

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

### Regressions in System.Memory.ReadOnlyMemory<Byte>

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

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

| 16.41 ns | 17.76 ns | 1.08 | 0.11 | False | | |

[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.Memory.ReadOnlyMemory*'
```

### System.Memory.ReadOnlyMemory<Byte>.Pin(Size: 512)

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

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Assessment

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[Perf] Windows/x86: 9 Regressions on 1/24/2026 4:18:23 AM +00:00

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