[Perf] Linux/x64: 11 Regressions on 7/10/2026 4:12:43 PM +00:00

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#76,183 opened on Jul 14, 2026 1 comment 0 reactions 0 assignees View on GitHub

aot-true arch-wasm arch-x64 branch-refs/heads/main compilationmode-wasm kind-micro Look Again os-linux perf-regression PGO runkind-micro untriaged wasm-aot

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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 | [c369fd627a26b606f36e6b3cbef6f25f3c00bbac](https://github.com/dotnet/runtime/commit/c369fd627a26b606f36e6b3cbef6f25f3c00bbac)
Compare | [2f3204f6e8df27046832bb56afa980a923deaf91](https://github.com/dotnet/runtime/commit/2f3204f6e8df27046832bb56afa980a923deaf91)
Diff | [Diff](https://github.com/dotnet/runtime/compare/c369fd627a26b606f36e6b3cbef6f25f3c00bbac...2f3204f6e8df27046832bb56afa980a923deaf91)
Configs | AOT:true, CompilationMode:wasm, RunKind:micro

### Regressions in System.Tests.Perf_String

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

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

| 1.23 μs | 1.39 μs | 1.13 | 0.17 | False | | |
|

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

| 59.91 ns | 66.85 ns | 1.12 | 0.16 | False | | |
|

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

| 60.35 ns | 66.79 ns | 1.11 | 0.11 | 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.Tests.Perf_String*'
```

### System.Tests.Perf_String.Split(s: "A B C D E F G H I J K L M N O P Q R S T U V W X Y Z", arr: [' '], options: None)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Tests.Perf_String.ToLowerInvariant(s: "TEST")

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Tests.Perf_String.ToLowerInvariant(s: "TeSt")

#### 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.Tests.Perf_Booleans

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

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

| 2.32 ms | 3.03 ms | 1.31 | 0.22 | False | | |
|

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

| 2.39 ms | 3.09 ms | 1.29 | 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.Text.Json.Tests.Perf_Booleans*'
```

### System.Text.Json.Tests.Perf_Booleans.WriteBooleans(Formatted: False, SkipValidation: True)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Text.Json.Tests.Perf_Booleans.WriteBooleans(Formatted: False, SkipValidation: False)

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

### Regressions in System.Tests.Perf_DateTime

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

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

| 73.44 ns | 83.46 ns | 1.14 | 0.15 | False | | |
|

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

| 64.74 ns | 70.76 ns | 1.09 | 0.13 | 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.Tests.Perf_DateTime*'
```

### System.Tests.Perf_DateTime.ToString(format: "r")

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Tests.Perf_DateTime.ToString(format: "s")

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

### Regressions in System.Tests.Perf_Enum

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

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

| 68.64 ns | 76.18 ns | 1.11 | 0.13 | 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.Tests.Perf_Enum*'
```

### System.Tests.Perf_Enum.ToString_Format_Flags_Large(value: All, format: "d")

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

### Regressions in System.Tests.Perf_Decimal

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

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

| 113.85 ns | 121.97 ns | 1.07 | 0.11 | 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.Tests.Perf_Decimal*'
```

### System.Tests.Perf_Decimal.TryParse(value: "123456.789")

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

### Regressions in System.Tests.Perf_Double

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

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

| 105.36 ns | 113.14 ns | 1.07 | 0.10 | 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.Tests.Perf_Double*'
```

### System.Tests.Perf_Double.TryParse(value: "12345")

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

### Regressions in System.Tests.Perf_Single

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

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

| 126.98 ns | 136.94 ns | 1.08 | 0.14 | 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.Tests.Perf_Single*'
```

### System.Tests.Perf_Single.TryParse(value: "-3.4028235E+38")

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

Contributor guide

No contributing guide indexed for this repository

Research direction

Start with the linked benchmark sources in src/benchmarks/micro/libraries/System.Runtime/Perf.String.cs and src/benchmarks/micro/libraries/System.Text.Json/Utf8JsonWriter/Perf.Booleans.cs, then run the provided benchmarks_ci.py commands. Compare the reported regressions against the baseline and compare commits and determine whether each regression is actionable. Done means the regressions are explained or fixed and the benchmark results are verified.

Written by the indexing model from the issue text.

Assessment

Tech stack: csharp, linux, python, ubuntu, wasm
Domain: performance, testing-qa
Issue type: Bug
Difficulty: 4/5
Estimated time: 3-5 days
Activity status: Quiet
Clarity: Needs clarification
Newbie friendliness: 28/100

[Perf] Linux/x64: 11 Regressions on 7/10/2026 4:12:43 PM +00:00

Description

Contributor guide

Research direction

Assessment

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