[Perf] Linux/arm64: 1 Improvement on 7/25/2026 4:19:05 PM +00:00

### Run Information

Name | Value
-- | --
Architecture | arm64
OS | azurelinux 3.0
Queue | CobaltAzureLinux
Baseline | [dad8c23384924cd46ba8d4482131416443b06445](https://github.com/dotnet/runtime/commit/dad8c23384924cd46ba8d4482131416443b06445)
Compare | [69d18c7af02f97ed5588f06adb0f63491c1b2be1](https://github.com/dotnet/runtime/commit/69d18c7af02f97ed5588f06adb0f63491c1b2be1)
Diff | [Diff](https://github.com/dotnet/runtime/compare/dad8c23384924cd46ba8d4482131416443b06445...69d18c7af02f97ed5588f06adb0f63491c1b2be1)
Configs | CompilationMode:tiered, RunKind:micro

### Improvements in System.Buffers.Text.Tests.Base64EncodeDecodeInPlaceTests

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

• [Base64DecodeInPlace - Duration of single invocation]()
• 📝 - [Benchmark Source]()
• [ADX - Test Multi Config 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.Text.Tests.Base64EncodeDecodeInPlaceTests*'
```

### System.Buffers.Text.Tests.Base64EncodeDecodeInPlaceTests.Base64DecodeInPlace(NumberOfBytes: 200000000)

#### 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 source at src/benchmarks/micro/libraries/System.Buffers/Base64Tests.cs lines 128-130 and reproduce it with the provided benchmarks_ci.py command. Review the linked test report and comparison data to identify a concrete runtime change; done requires a validated result for System.Buffers.Text.Tests.Base64EncodeDecodeInPlaceTests.

Written by the indexing model from the issue text.