[Perf] Linux/arm64: 16 Regressions on 8/28/2026 11:31:31 PM +00:00

Open

#79,258 opened on Sep 10, 2026 1 comment 0 reactions 0 assignees View on GitHub

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

Dominant language: No language data
Stars: 10
Forks: 8
PR merge metrics: PR metrics pending

Description

### Run Information

Name | Value
-- | --
Architecture | arm64
OS | ubuntu 22.04
Queue | AmpereUbuntu
Baseline | [b4e9424c4f9e05944f3fd1ef1277e85e857b8036](https://github.com/dotnet/runtime/commit/b4e9424c4f9e05944f3fd1ef1277e85e857b8036)
Compare | [aa036afce592ad80e938a35bd376222fb232cba9](https://github.com/dotnet/runtime/commit/aa036afce592ad80e938a35bd376222fb232cba9)
Diff | [Diff](https://github.com/dotnet/runtime/compare/b4e9424c4f9e05944f3fd1ef1277e85e857b8036...aa036afce592ad80e938a35bd376222fb232cba9)
Configs | CompilationMode:tiered, RunKind:micro

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

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]()

| 306.97 ns | 761.45 ns | 2.48 | 0.49 | False | | |
|

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

| 248.76 ns | 521.89 ns | 2.10 | 0.54 | False | | |
|

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

| 23.61 μs | 48.87 μs | 2.07 | 0.10 | False | | |
|

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

| 23.66 μs | 38.16 μs | 1.61 | 0.11 | False | | |
|

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

| 968.52 ns | 1512.41 ns | 1.56 | 0.28 | 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
python3 .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Buffers.Tests.RentReturnArrayPoolTests*'
```

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

#### ETL Files

#### Histogram

#### JIT Disasms

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

#### ETL Files

#### Histogram

#### JIT Disasms

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

#### ETL Files

#### Histogram

#### JIT Disasms

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

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Buffers.Tests.RentReturnArrayPoolTests<Object>.MultipleSerial(RentalSize: 4096, ManipulateArray: False, 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.IO.Tests.Perf_FileStream

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

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

| 1.79 ms | 2.53 ms | 1.42 | 0.23 | False | | |
|

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

| 153.33 ms | 205.67 ms | 1.34 | 0.16 | False | | |
|

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

| 158.61 ms | 210.12 ms | 1.32 | 0.14 | 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.IO.Tests.Perf_FileStream*'
```

### System.IO.Tests.Perf_FileStream.CopyToFileAsync(fileSize: 1048576, options: Asynchronous)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.IO.Tests.Perf_FileStream.CopyToFileAsync(fileSize: 104857600, options: Asynchronous)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.IO.Tests.Perf_FileStream.CopyToFileAsync(fileSize: 104857600, options: None)

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

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

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

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

| 17.48 μs | 35.45 μs | 2.03 | 0.09 | False | | |
|

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

| 882.52 ns | 1458.79 ns | 1.65 | 0.29 | False | | |
|

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

| 17.46 μs | 19.66 μs | 1.13 | 0.07 | 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.Buffers.Tests.RentReturnArrayPoolTests*'
```

### System.Buffers.Tests.RentReturnArrayPoolTests<Byte>.MultipleSerial(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: False)

#### ETL Files

#### Histogram

#### JIT Disasms

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

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

### Regressions in System.Formats.Tar.Tests.Perf_TarFile

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

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

| 219.35 μs | 266.14 μs | 1.21 | 0.55 | 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.Formats.Tar.Tests.Perf_TarFile*'
```

### System.Formats.Tar.Tests.Perf_TarFile.CreateFromDirectory_Path_Async

#### 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]()

| 601.01 ns | 1565.98 ns | 2.61 | 0.47 | 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.Threading.Tasks.ValueTaskPerfTest*'
```

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

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

### Regressions in System.Threading.Channels.Tests.BoundedChannelPerfTests

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

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

| 11.74 ms | 23.75 ms | 2.02 | 0.51 | 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.Threading.Channels.Tests.BoundedChannelPerfTests*'
```

### System.Threading.Channels.Tests.BoundedChannelPerfTests.PingPong

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

---

### Run Information

### Regressions in System.Threading.Channels.Tests.SpscUnboundedChannelPerfTests

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

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

| 10.95 ms | 22.70 ms | 2.07 | 0.48 | 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.Threading.Channels.Tests.SpscUnboundedChannelPerfTests*'
```

### System.Threading.Channels.Tests.SpscUnboundedChannelPerfTests.PingPong

#### 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]()

| 455.53 ns | 957.04 ns | 2.10 | 0.52 | 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.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 sources linked in dotnet/performance, including src/benchmarks/micro/libraries/System.Buffers/ArrayPoolTests.cs, and review the baseline and compare commits. Run scripts/benchmarks_ci.py with the provided filter on Linux/arm64, then use the regression report and profiling workflow to identify and resolve the reported performance regressions.

Written by the indexing model from the issue text.

Assessment

Tech stack: linux, python, ubuntu
Domain: performance
Issue type: Bug
Difficulty: 4/5
Estimated time: 3-5 days
Activity status: Active
Clarity: Needs clarification
Newbie friendliness: 35/100

[Perf] Linux/arm64: 16 Regressions on 8/28/2026 11:31:31 PM +00:00

Description

Contributor guide

Research direction

Assessment

Get new issues in your inbox