[Perf] Linux/arm64: 5 Regressions on 5/7/2026 3:57:15 PM +00:00

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#72,945 opened on May 14, 2026 1 comment 0 reactions 0 assignees View on GitHub

arch-arm64 branch-refs/heads/main compilationmode-tiered kind-micro Look Again os-linux perf-regression runkind-micro runtime-coreclr

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Forks: 8
PR merge metrics: PR metrics pending

Description

### Run Information

Name | Value
-- | --
Architecture | arm64
OS | azurelinux 3.0
Queue | CobaltAzureLinux
Baseline | [cdbf0c2ba8a84fdc9d83f019baa2103a0afd580b](https://github.com/dotnet/runtime/commit/cdbf0c2ba8a84fdc9d83f019baa2103a0afd580b)
Compare | [c3caf4d3163c429efbdefe7756a71702e9e6c982](https://github.com/dotnet/runtime/commit/c3caf4d3163c429efbdefe7756a71702e9e6c982)
Diff | [Diff](https://github.com/dotnet/runtime/compare/cdbf0c2ba8a84fdc9d83f019baa2103a0afd580b...c3caf4d3163c429efbdefe7756a71702e9e6c982)
Configs | CompilationMode:tiered, RunKind:micro

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

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]()

| 190.03 μs | 305.48 μs | 1.61 | 0.21 | False | | |
|

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

| 185.68 μs | 227.74 μs | 1.23 | 0.17 | 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.Collections.ContainsTrue*'
```

### System.Collections.ContainsTrue<String>.LinkedList(Size: 512)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Collections.ContainsTrue<String>.Stack(Size: 512)

#### 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.Reader.Tests.Perf_Base64

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

[ReadBase64EncodedByteArray_HeavyEscaping - Duration of single invocation]()
📝 - [Benchmark Source]()
[ADX - Test Multi Config Graph]()

| 527.14 ns | 827.24 ns | 1.57 | 0.22 | 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.Reader.Tests.Perf_Base64*'
```

### System.Text.Json.Reader.Tests.Perf_Base64.ReadBase64EncodedByteArray_HeavyEscaping(NumberOfBytes: 1000)

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

### Regressions in System.Collections.CtorFromCollection<Int32>

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

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

| 45.36 μs | 72.21 μs | 1.59 | 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.Collections.CtorFromCollection*'
```

### System.Collections.CtorFromCollection<Int32>.ImmutableDictionary(Size: 512)

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

### Regressions in System.Tests.Perf_Char

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

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

| 16.40 ns | 26.58 ns | 1.62 | 0.25 | 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.Tests.Perf_Char*'
```

### System.Tests.Perf_Char.Char_IsUpper(input: "Good afternoon, Constable!")

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

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[Perf] Linux/arm64: 5 Regressions on 5/7/2026 3:57:15 PM +00:00

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