[Perf] Linux/arm64: 11 Regressions on 7/13/2026 8:32:42 PM +00:00

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#76,333 opened on Jul 16, 2026 1 comment 0 reactions 0 assignees View on GitHub

arch-arm64 bdn-update branch-refs/heads/main compilationmode-tiered kind-micro Look Again os-linux perf-regression r2rtype-r2r_interpreter runkind-micro runtime-coreclr untriaged

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Description

### Run Information

Name | Value
-- | --
Architecture | arm64
OS | azurelinux 3.0
Queue | CobaltAzureLinux
Baseline | [a90733cc40d6c7037a37d9c2b5c2403b8cac490f](https://github.com/dotnet/runtime/commit/a90733cc40d6c7037a37d9c2b5c2403b8cac490f)
Compare | [f2b30309fd488f1c3fd41c18723a7c80a81f4c67](https://github.com/dotnet/runtime/commit/f2b30309fd488f1c3fd41c18723a7c80a81f4c67)
Diff | [Diff](https://github.com/dotnet/runtime/compare/a90733cc40d6c7037a37d9c2b5c2403b8cac490f...f2b30309fd488f1c3fd41c18723a7c80a81f4c67)
Configs | CompilationMode:tiered, R2RType:r2r_interpreter, RunKind:micro

### Regressions in System.Buffers.Tests.RentReturnArrayPoolTests<Byte>

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

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

| 2.55 μs | 4.40 μs | 1.72 | 0.29 | False | | |
|

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

| 2.55 μs | 4.39 μs | 1.72 | 0.23 | False | | |
|

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

| 3.00 μs | 4.49 μs | 1.50 | 0.47 | False | | |
|

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

| 2.33 μs | 3.39 μs | 1.45 | 0.28 | False | | |
|

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

| 991.01 ns | 1409.93 ns | 1.42 | 0.19 | False | | |
|

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

| 2.45 μs | 3.45 μs | 1.41 | 0.09 | False | | |

![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
py .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Buffers.Tests.RentReturnArrayPoolTests*'
```

### System.Buffers.Tests.RentReturnArrayPoolTests<Byte>.SingleSerial(RentalSize: 4096, ManipulateArray: True, Async: True, UseSharedPool: True)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Buffers.Tests.RentReturnArrayPoolTests<Byte>.SingleSerial(RentalSize: 4096, ManipulateArray: True, Async: True, UseSharedPool: False)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Buffers.Tests.RentReturnArrayPoolTests<Byte>.ProducerConsumer(RentalSize: 4096, ManipulateArray: True, Async: True, UseSharedPool: True)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Buffers.Tests.RentReturnArrayPoolTests<Byte>.MultipleSerial(RentalSize: 4096, ManipulateArray: False, Async: True, UseSharedPool: True)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Buffers.Tests.RentReturnArrayPoolTests<Byte>.MultipleSerial(RentalSize: 4096, ManipulateArray: False, Async: True, UseSharedPool: False)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Buffers.Tests.RentReturnArrayPoolTests<Byte>.ProducerConsumer(RentalSize: 4096, ManipulateArray: True, Async: True, UseSharedPool: False)

#### 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<StructRecord>

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]()

| 3.84 μs | 4.84 μs | 1.26 | 0.20 | False | | |
|

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

| 3.32 μs | 4.16 μs | 1.25 | 0.15 | 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<StructRecord>.DeserializeFromStream(Mode: Reflection)

#### ETL Files

#### Histogram

#### JIT Disasms

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

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

### Regressions in System.Threading.Tasks.ValueTaskPerfTest

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

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

| 1.78 μs | 5.00 μs | 2.81 | 0.21 | 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.Threading.Tasks.ValueTaskPerfTest*'
```

### System.Threading.Tasks.ValueTaskPerfTest.CreateAndAwait_FromYieldingAsyncMethod

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

### Regressions in System.Memory.Span<Int32>

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

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

| 732.45 ns | 865.09 ns | 1.18 | 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
py .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Memory.Span*'
```

### System.Memory.Span<Int32>.ToArray(Size: 3000)

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

### Regressions in System.Threading.Tasks.Tests.Perf_AsyncMethods

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

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

| 951.73 ns | 1419.63 ns | 1.49 | 0.33 | 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.Threading.Tasks.Tests.Perf_AsyncMethods*'
```

### System.Threading.Tasks.Tests.Perf_AsyncMethods.SingleYieldMethodInvocation

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

Contributor guide

No contributing guide indexed for this repository

Research direction

Start with the benchmark source at src/benchmarks/micro/libraries/System.Buffers/ArrayPoolTests.cs, especially lines 48-60 and 83-149, and read docs/benchmarking-workflow-dotnet-runtime.md. Run the provided benchmarks_ci.py command, then compare the ARM64 AzureLinux results with the linked baseline and test commits. Done means the reported regressions are explained and the relevant benchmark performance is restored or the issue is narrowed to an actionable cause.

Written by the indexing model from the issue text.

Assessment

Tech stack: git, linux, python
Domain: performance, testing, tooling
Issue type: Bug
Difficulty: 4/5
Estimated time: 3-5 days
Activity status: Quiet
Clarity: Needs clarification
Newbie friendliness: 42/100

[Perf] Linux/arm64: 11 Regressions on 7/13/2026 8:32:42 PM +00:00

Description

Contributor guide

Research direction

Assessment

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