[Perf] Linux/arm64: 5 Improvements on 6/30/2026 6:17:45 PM +00:00

### Run Information

Name | Value
-- | --
Architecture | arm64
OS | ubuntu 22.04
Queue | AmpereUbuntu
Baseline | [8b16f838b402a42d4edd4d6ed299ed2d4508a2a2](https://github.com/dotnet/runtime/commit/8b16f838b402a42d4edd4d6ed299ed2d4508a2a2)
Compare | [8edc1cf5f0229b2bfd25445d5baac0ded07f615e](https://github.com/dotnet/runtime/commit/8edc1cf5f0229b2bfd25445d5baac0ded07f615e)
Diff | [Diff](https://github.com/dotnet/runtime/compare/8b16f838b402a42d4edd4d6ed299ed2d4508a2a2...8edc1cf5f0229b2bfd25445d5baac0ded07f615e)
Configs | CompilationMode:tiered, RunKind:micro

### Improvements in System.Text.Tests.Perf_StringBuilder

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

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

| 354.38 μs | 313.50 μs | 0.88 | 0.48 | False | | |
|

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

| 391.96 ns | 352.81 ns | 0.90 | 0.12 | 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.Tests.Perf_StringBuilder*'
```

### System.Text.Tests.Perf_StringBuilder.Append_Char(length: 100000)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Text.Tests.Perf_StringBuilder.Append_Char_Capacity(length: 100)

#### 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

Name | Value
-- | --
Architecture | arm64
OS | ubuntu 22.04
Queue | AmpereUbuntu
Baseline | [8b16f838b402a42d4edd4d6ed299ed2d4508a2a2](https://github.com/dotnet/runtime/commit/8b16f838b402a42d4edd4d6ed299ed2d4508a2a2)
Compare | [8edc1cf5f0229b2bfd25445d5baac0ded07f615e](https://github.com/dotnet/runtime/commit/8edc1cf5f0229b2bfd25445d5baac0ded07f615e)
Diff | [Diff](https://github.com/dotnet/runtime/compare/8b16f838b402a42d4edd4d6ed299ed2d4508a2a2...8edc1cf5f0229b2bfd25445d5baac0ded07f615e)
Configs | CompilationMode:tiered, RunKind:micro

### Improvements in System.Diagnostics.Perf_Process

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

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

| 543.22 μs | 478.56 μs | 0.88 | 0.38 | False | | |
|

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

| 1.66 ms | 1.51 ms | 0.91 | 0.06 | 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.Diagnostics.Perf_Process*'
```

### System.Diagnostics.Perf_Process.Start

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Diagnostics.Perf_Process.StartAndWaitForExit

#### 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

Name | Value
-- | --
Architecture | arm64
OS | ubuntu 22.04
Queue | AmpereUbuntu
Baseline | [8b16f838b402a42d4edd4d6ed299ed2d4508a2a2](https://github.com/dotnet/runtime/commit/8b16f838b402a42d4edd4d6ed299ed2d4508a2a2)
Compare | [8edc1cf5f0229b2bfd25445d5baac0ded07f615e](https://github.com/dotnet/runtime/commit/8edc1cf5f0229b2bfd25445d5baac0ded07f615e)
Diff | [Diff](https://github.com/dotnet/runtime/compare/8b16f838b402a42d4edd4d6ed299ed2d4508a2a2...8edc1cf5f0229b2bfd25445d5baac0ded07f615e)
Configs | CompilationMode:tiered, RunKind:micro

### Improvements in System.Net.Tests.DnsTests

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

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

| 184.93 μs | 156.26 μs | 0.84 | 0.45 | 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.Net.Tests.DnsTests*'
```

### System.Net.Tests.DnsTests.GetHostAddressesAsync

#### 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)

Start with the benchmark sources named in the report: src/benchmarks/micro/libraries/System.Text/Perf.StringBuilder.cs, System.Diagnostics/Perf_Process.cs, and System.Net.Primitives/DnsTests.cs. Read the benchmarking workflow documentation, then run benchmarks_ci.py with the reported filters on Linux/arm64. Done means determining whether the reported improvements are actionable and documenting or validating the result.

Written by the indexing model from the issue text.