[Perf] Windows/x86: 14 Regressions on 6/1/2026 11:49:46 AM +00:00

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#74,244 opened on Jun 9, 2026 0 comments 0 reactions 0 assignees View on GitHub

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

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Forks: 8
PR merge metrics: PR metrics pending

Description

### Run Information

Name | Value
-- | --
Architecture | x86
OS | Windows 10.0.22631
Queue | ViperWindows
Baseline | [6963a5964693f9c439d100b4bba9ae01af697dc1](https://github.com/dotnet/runtime/commit/6963a5964693f9c439d100b4bba9ae01af697dc1)
Compare | [a82b35567c0b55dbd892abace73a3ad4ac859ccb](https://github.com/dotnet/runtime/commit/a82b35567c0b55dbd892abace73a3ad4ac859ccb)
Diff | [Diff](https://github.com/dotnet/runtime/compare/6963a5964693f9c439d100b4bba9ae01af697dc1...a82b35567c0b55dbd892abace73a3ad4ac859ccb)
Configs | CompilationMode:tiered, RunKind:micro

### Regressions in System.Text.Json.Serialization.Tests.ReadJson<ArrayList>

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]()

| 10.76 μs | 12.39 μs | 1.15 | 0.06 | False | | |
|

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

| 12.42 μs | 14.08 μs | 1.13 | 0.17 | False | | |
|

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

| 11.13 μs | 12.55 μs | 1.13 | 0.12 | False | | |
|

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

| 11.14 μs | 12.38 μs | 1.11 | 0.03 | False | | |
|

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

| 11.12 μs | 12.34 μs | 1.11 | 0.10 | False | | |

![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
py .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Text.Json.Serialization.Tests.ReadJson*'
```

### System.Text.Json.Serialization.Tests.ReadJson<ArrayList>.DeserializeFromUtf8Bytes(Mode: Reflection)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Text.Json.Serialization.Tests.ReadJson<ArrayList>.DeserializeFromReader(Mode: Reflection)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Text.Json.Serialization.Tests.ReadJson<ArrayList>.DeserializeFromString(Mode: Reflection)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Text.Json.Serialization.Tests.ReadJson<ArrayList>.DeserializeFromUtf8Bytes(Mode: SourceGen)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Text.Json.Serialization.Tests.ReadJson<ArrayList>.DeserializeFromString(Mode: SourceGen)

#### 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.Text.Json.Serialization.Tests.ReadJson<BinaryDataPayload>

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

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

| 383.09 ns | 433.60 ns | 1.13 | 0.02 | False | | |
|

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

| 386.73 ns | 417.84 ns | 1.08 | 0.04 | 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.Text.Json.Serialization.Tests.ReadJson*'
```

### System.Text.Json.Serialization.Tests.ReadJson<BinaryDataPayload>.DeserializeFromReader(Mode: Reflection)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Text.Json.Serialization.Tests.ReadJson<BinaryDataPayload>.DeserializeFromReader(Mode: SourceGen)

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

### Regressions in System.Text.Json.Serialization.Tests.ReadJson<LoginViewModel>

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

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

| 376.45 ns | 417.82 ns | 1.11 | 0.04 | False | | |
|

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

| 383.89 ns | 423.77 ns | 1.10 | 0.05 | 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.Text.Json.Serialization.Tests.ReadJson*'
```

### System.Text.Json.Serialization.Tests.ReadJson<LoginViewModel>.DeserializeFromReader(Mode: SourceGen)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Text.Json.Serialization.Tests.ReadJson<LoginViewModel>.DeserializeFromReader(Mode: Reflection)

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

### Regressions in System.Memory.ReadOnlySequence

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

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

| 1.15 ns | 4.12 ns | 3.57 | 0.05 | 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.Memory.ReadOnlySequence*'
```

### System.Memory.ReadOnlySequence.Slice_Start(Segment: Single)

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

### Regressions in System.Text.Json.Serialization.Tests.ReadJson<MyEventsListerViewModel>

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

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

| 178.02 μs | 212.24 μs | 1.19 | 0.03 | 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.Json.Serialization.Tests.ReadJson*'
```

### System.Text.Json.Serialization.Tests.ReadJson<MyEventsListerViewModel>.DeserializeFromStream(Mode: Reflection)

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

Name | Value
-- | --
Architecture | x86
OS | Windows 10.0.22631
Queue | ViperWindows
Baseline | [f2d5042ceaea5642bac6bde8a1a5765afcbf2ef4](https://github.com/dotnet/runtime/commit/f2d5042ceaea5642bac6bde8a1a5765afcbf2ef4)
Compare | [a82b35567c0b55dbd892abace73a3ad4ac859ccb](https://github.com/dotnet/runtime/commit/a82b35567c0b55dbd892abace73a3ad4ac859ccb)
Diff | [Diff](https://github.com/dotnet/runtime/compare/f2d5042ceaea5642bac6bde8a1a5765afcbf2ef4...a82b35567c0b55dbd892abace73a3ad4ac859ccb)
Configs | CompilationMode:tiered, RunKind:micro

### Regressions in System.Diagnostics.Perf_Activity

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

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

| 9.21 μs | 13.60 μs | 1.48 | 0.20 | 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.Diagnostics.Perf_Activity*'
```

### System.Diagnostics.Perf_Activity.EnumerateActivityLinksLarge

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

### Regressions in System.Memory.SequenceReader

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

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

| 56.02 ns | 63.73 ns | 1.14 | 0.18 | 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.Memory.SequenceReader*'
```

### System.Memory.SequenceReader.TryReadTo

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

### Regressions in MicroBenchmarks.Serializers.Json_FromStream<MyEventsListerViewModel>

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

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

| 183.05 μs | 204.86 μs | 1.12 | 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 'MicroBenchmarks.Serializers.Json_FromStream*'
```

### MicroBenchmarks.Serializers.Json_FromStream<MyEventsListerViewModel>.SystemTextJson_Reflection_

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

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[Perf] Windows/x86: 14 Regressions on 6/1/2026 11:49:46 AM +00:00

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