[Perf] Linux/arm64: 5 Improvements on 6/28/2026 1:49:22 PM +00:00

### Run Information

Name | Value
-- | --
Architecture | arm64
OS | azurelinux 3.0
Queue | CobaltAzureLinux
Baseline | [567a079a3f45e2e217815b49e1e09fa76ab72f11](https://github.com/dotnet/runtime/commit/567a079a3f45e2e217815b49e1e09fa76ab72f11)
Compare | [33db1610a13c814c71deb0865a23927305eecb5a](https://github.com/dotnet/runtime/commit/33db1610a13c814c71deb0865a23927305eecb5a)
Diff | [Diff](https://github.com/dotnet/runtime/compare/567a079a3f45e2e217815b49e1e09fa76ab72f11...33db1610a13c814c71deb0865a23927305eecb5a)
Configs | CompilationMode:tiered, R2RType:r2r_interpreter, RunKind:micro

### Improvements in System.Text.Json.Serialization.Tests.WriteJson<ImmutableSortedDictionary<String, String>>

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

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

| 67.14 μs | 52.57 μs | 0.78 | 0.14 | False | | |
|

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

| 67.08 μs | 52.61 μs | 0.78 | 0.09 | False | | |
|

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

| 64.21 μs | 50.72 μs | 0.79 | 0.10 | False | | |
|

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

| 67.85 μs | 53.70 μs | 0.79 | 0.14 | False | | |
|

• [SerializeToUtf8Bytes - Duration of single invocation]()
• 📝 - [Benchmark Source]()
• [ADX - Test Multi Config Graph]()

| 67.64 μs | 53.97 μs | 0.80 | 0.09 | False | | |

![graph]()
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[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.WriteJson>*'
```

### System.Text.Json.Serialization.Tests.WriteJson<ImmutableSortedDictionary<String, String>>.SerializeToString(Mode: SourceGen)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Text.Json.Serialization.Tests.WriteJson<ImmutableSortedDictionary<String, String>>.SerializeToStream(Mode: SourceGen)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Text.Json.Serialization.Tests.WriteJson<ImmutableSortedDictionary<String, String>>.SerializeToWriter(Mode: SourceGen)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Text.Json.Serialization.Tests.WriteJson<ImmutableSortedDictionary<String, String>>.SerializeObjectProperty(Mode: SourceGen)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Text.Json.Serialization.Tests.WriteJson<ImmutableSortedDictionary<String, String>>.SerializeToUtf8Bytes(Mode: SourceGen)

#### 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 src/benchmarks/micro/libraries/System.Text.Json/Serializer/WriteJson.cs at lines 75-98 and the benchmarking workflow documentation, then run the provided benchmarks_ci.py command with its filter. Compare the ARM64 AzureLinux results with the linked baseline and compare commits; done means a documented triage outcome for the five reported improvements.

Written by the indexing model from the issue text.