[Perf] Linux/x64: 22 Regressions on 4/28/2026 6:34:45 PM +00:00

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#72,646 opened on May 7, 2026 1 comment 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

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Forks: 8
PR merge metrics: PR metrics pending

Description

### Run Information

Name | Value
-- | --
Architecture | x64
OS | ubuntu 22.04
Queue | ViperUbuntu
Baseline | [2e4f24bdff2049c533e89260fc74a45ed27fe309](https://github.com/dotnet/runtime/commit/2e4f24bdff2049c533e89260fc74a45ed27fe309)
Compare | [5391e9ec4fb4ab1bcebe4dbfc33bf4b8fdf01981](https://github.com/dotnet/runtime/commit/5391e9ec4fb4ab1bcebe4dbfc33bf4b8fdf01981)
Diff | [Diff](https://github.com/dotnet/runtime/compare/2e4f24bdff2049c533e89260fc74a45ed27fe309...5391e9ec4fb4ab1bcebe4dbfc33bf4b8fdf01981)
Configs | CompilationMode:wasm, RunKind:micro, RuntimeType:coreclr

### Regressions in System.Text.Encodings.Web.Tests.Perf_Encoders

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

[EncodeUtf16 - Duration of single invocation]()
📝 - [Benchmark Source]()
[ADX - Test Multi Config Graph]()

| 88.78 μs | 102.14 μs | 1.15 | 0.29 | False | | |
|

[EncodeUtf16 - Duration of single invocation]()
📝 - [Benchmark Source]()
[ADX - Test Multi Config Graph]()

| 76.98 μs | 88.39 μs | 1.15 | 0.33 | False | | |
|

[EncodeUtf16 - Duration of single invocation]()
📝 - [Benchmark Source]()
[ADX - Test Multi Config Graph]()

| 7.16 μs | 8.16 μs | 1.14 | 0.27 | False | | |
|

[EncodeUtf16 - Duration of single invocation]()
📝 - [Benchmark Source]()
[ADX - Test Multi Config Graph]()

| 84.47 μs | 96.12 μs | 1.14 | 0.28 | False | | |
|

[EncodeUtf16 - Duration of single invocation]()
📝 - [Benchmark Source]()
[ADX - Test Multi Config Graph]()

| 81.78 μs | 90.43 μs | 1.11 | 0.29 | False | | |
|

[EncodeUtf16 - Duration of single invocation]()
📝 - [Benchmark Source]()
[ADX - Test Multi Config Graph]()

| 13.68 μs | 14.90 μs | 1.09 | 0.35 | False | | |
|

[EncodeUtf8 - Duration of single invocation]()
📝 - [Benchmark Source]()
[ADX - Test Multi Config Graph]()

| 14.72 μs | 15.74 μs | 1.07 | 0.33 | 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
python3 .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Text.Encodings.Web.Tests.Perf_Encoders*'
```

### System.Text.Encodings.Web.Tests.Perf_Encoders.EncodeUtf16(arguments: Url,&lorem ipsum=dolor sit amet,512)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Text.Encodings.Web.Tests.Perf_Encoders.EncodeUtf16(arguments: JavaScript,no escaping required,512)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Text.Encodings.Web.Tests.Perf_Encoders.EncodeUtf16(arguments: UnsafeRelaxed,no <escaping /> required,16)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Text.Encodings.Web.Tests.Perf_Encoders.EncodeUtf16(arguments: JavaScript,&Hello+<World>!,512)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Text.Encodings.Web.Tests.Perf_Encoders.EncodeUtf16(arguments: Url,�2020,512)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Text.Encodings.Web.Tests.Perf_Encoders.EncodeUtf16(arguments: JavaScript,&Hello+<World>!,16)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Text.Encodings.Web.Tests.Perf_Encoders.EncodeUtf8(arguments: Url,�2020,16)

#### 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.Perf_Frozen<Int16>

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

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

| 3.34 μs | 3.66 μs | 1.10 | 0.32 | False | | |
|

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

| 247.53 μs | 264.05 μs | 1.07 | 0.43 | False | | |
|

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

| 3.70 μs | 3.89 μs | 1.05 | 0.20 | False | | |

![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.Collections.Perf_Frozen*'
```

### System.Collections.Perf_Frozen<Int16>.Contains_True(Count: 4)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Collections.Perf_Frozen<Int16>.ToFrozenSet(Count: 64)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Collections.Perf_Frozen<Int16>.TryGetValue_True(Count: 4)

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

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

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

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

| 765.78 μs | 857.81 μs | 1.12 | 0.28 | False | | |
|

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

| 13.20 μs | 14.16 μs | 1.07 | 0.16 | 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
python3 .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.IO.Tests.Perf_File*'
```

### System.IO.Tests.Perf_File.AppendAllText(size: 10000)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.IO.Tests.Perf_File.Exists

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

### Regressions in System.Collections.ContainsKeyFalse<Int32, Int32>

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

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

| 159.94 μs | 178.47 μs | 1.12 | 0.46 | False | | |
|

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

| 742.55 μs | 802.11 μs | 1.08 | 0.32 | 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
python3 .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Collections.ContainsKeyFalse*'
```

### System.Collections.ContainsKeyFalse<Int32, Int32>.FrozenDictionary(Size: 512)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Collections.ContainsKeyFalse<Int32, Int32>.ImmutableSortedDictionary(Size: 512)

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

### Regressions in System.IO.Tests.MemoryStreamChunkedTests

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

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

| 21.63 μs | 23.75 μs | 1.10 | 0.31 | False | | |
|

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

| 779.37 ns | 848.85 ns | 1.09 | 0.27 | 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
python3 .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.IO.Tests.MemoryStreamChunkedTests*'
```

### System.IO.Tests.MemoryStreamChunkedTests.WriteSpan(ChunkSize: 4096)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.IO.Tests.MemoryStreamChunkedTests.CopyToWithBufferSize(ChunkSize: 4096)

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

### Regressions in Benchstone.BenchF.InvMt

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

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

| 127.08 ms | 143.81 ms | 1.13 | 0.56 | 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
python3 .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'Benchstone.BenchF.InvMt*'
```

### Benchstone.BenchF.InvMt.Test

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

### Regressions in MicroBenchmarks.Serializers.Xml_ToStream<SimpleStructWithProperties>

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

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

| 25.71 μs | 27.85 μs | 1.08 | 0.38 | 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
python3 .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'MicroBenchmarks.Serializers.Xml_ToStream*'
```

### MicroBenchmarks.Serializers.Xml_ToStream<SimpleStructWithProperties>.DataContractSerializer_BinaryXml_

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

### Regressions in System.Collections.DictionaryTryRemove<String, String>

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

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

| 2.63 ms | 2.93 ms | 1.11 | 0.41 | 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
python3 .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Collections.DictionaryTryRemove*'
```

### System.Collections.DictionaryTryRemove<String, String>.TryRemove_Hit(Size: 512)

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

### Regressions in System.Text.Json.Document.Tests.Perf_DocumentParse

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]()

| 190.73 ms | 205.46 ms | 1.08 | 0.34 | 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
python3 .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Text.Json.Document.Tests.Perf_DocumentParse*'
```

### System.Text.Json.Document.Tests.Perf_DocumentParse.Parse(IsDataIndented: True, TestRandomAccess: False, TestCase: Json400KB)

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

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

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

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

| 1.05 ms | 1.14 ms | 1.09 | 0.43 | 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
python3 .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Collections.RemoveFalse*'
```

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

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

### Regressions in PerfLabTests.DictionaryExpansion

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

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

| 25.09 μs | 26.55 μs | 1.06 | 0.35 | 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
python3 .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'PerfLabTests.DictionaryExpansion*'
```

### PerfLabTests.DictionaryExpansion.ExpandDictionaries

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

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[Perf] Linux/x64: 22 Regressions on 4/28/2026 6:34:45 PM +00:00

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