[Perf] Windows/x86: 6 Regressions on 7/30/2026 6:50:50 PM +00:00

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#77,234 opened on Aug 4, 2026 1 comment 0 reactions 0 assignees View on GitHub

arch-x86 branch-refs/heads/main compilationmode-tiered kind-micro Look Again 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 | [72dac24a0e6fa1047002858a762f36c88e53850b](https://github.com/dotnet/runtime/commit/72dac24a0e6fa1047002858a762f36c88e53850b)
Compare | [640b326fc81d94d410753b67c0f89b166d6666df](https://github.com/dotnet/runtime/commit/640b326fc81d94d410753b67c0f89b166d6666df)
Diff | [Diff](https://github.com/dotnet/runtime/compare/72dac24a0e6fa1047002858a762f36c88e53850b...640b326fc81d94d410753b67c0f89b166d6666df)
Configs | CompilationMode:tiered, RunKind:micro

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

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

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

| 555.52 μs | 783.18 μs | 1.41 | 0.00 | 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.Xml_FromStream*'
```

### MicroBenchmarks.Serializers.Xml_FromStream<MyEventsListerViewModel>.XmlSerializer_

#### 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 MicroBenchmarks.Serializers.Xml_FromStream<SimpleStructWithProperties>

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

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

| 2.51 μs | 2.77 μs | 1.10 | 0.01 | 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.Xml_FromStream*'
```

### MicroBenchmarks.Serializers.Xml_FromStream<SimpleStructWithProperties>.XmlSerializer_

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

### Regressions in MicroBenchmarks.Serializers.Xml_FromStream<IndexViewModel>

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

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

| 54.80 μs | 81.55 μs | 1.49 | 0.01 | 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.Xml_FromStream*'
```

### MicroBenchmarks.Serializers.Xml_FromStream<IndexViewModel>.XmlSerializer_

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

### Regressions in MicroBenchmarks.Serializers.Xml_FromStream<LoginViewModel>

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

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

| 2.85 μs | 3.30 μs | 1.16 | 0.01 | 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.Xml_FromStream*'
```

### MicroBenchmarks.Serializers.Xml_FromStream<LoginViewModel>.XmlSerializer_

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

### Regressions in MicroBenchmarks.Serializers.Xml_FromStream<CollectionsOfPrimitives>

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

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

| 362.51 μs | 676.70 μs | 1.87 | 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.Xml_FromStream*'
```

### MicroBenchmarks.Serializers.Xml_FromStream<CollectionsOfPrimitives>.XmlSerializer_

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

### Regressions in MicroBenchmarks.Serializers.Xml_FromStream<Location>

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

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

| 3.68 μs | 5.09 μs | 1.38 | 0.01 | 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.Xml_FromStream*'
```

### MicroBenchmarks.Serializers.Xml_FromStream<Location>.XmlSerializer_

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

Contributor guide

No contributing guide indexed for this repository

Research direction

Start with src/benchmarks/micro/Serializers/Xml_FromStream.cs lines 42-48 and run the provided benchmarks_ci.py command for the listed filters. Compare the baseline and test reports, including the linked commit diff and profiling workflow, to identify the regression. Done means determining the cause and verifying the affected Windows/x86 benchmark results no longer regress.

Written by the indexing model from the issue text.

Assessment

Domain: performance
Issue type: Bug
Difficulty: 4/5
Estimated time: 3-5 days
Activity status: Quiet
Clarity: Mostly clear
Newbie friendliness: 45/100

[Perf] Windows/x86: 6 Regressions on 7/30/2026 6:50:50 PM +00:00

Description

Contributor guide

Research direction

Assessment

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