[Perf] Linux/x64: 2 Regressions on 8/5/2026 1:23:13 AM +00:00

### Run Information

Name | Value
-- | --
Architecture | x64
OS | ubuntu 22.04
Queue | ViperUbuntu
Baseline | [2dd5330804f9d4f49599d82c90a67892d4dd8af0](https://github.com/dotnet/runtime/commit/2dd5330804f9d4f49599d82c90a67892d4dd8af0)
Compare | [c8f97975ab0d8ff84aebf176829e17f7c7052f03](https://github.com/dotnet/runtime/commit/c8f97975ab0d8ff84aebf176829e17f7c7052f03)
Diff | [Diff](https://github.com/dotnet/runtime/compare/2dd5330804f9d4f49599d82c90a67892d4dd8af0...c8f97975ab0d8ff84aebf176829e17f7c7052f03)
Configs | AOT:true, CompilationMode:wasm, RunKind:micro

### Regressions in System.Buffers.Tests.ReadOnlySequenceTests<Char>

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

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

| 51.59 ns | 59.24 ns | 1.15 | 0.10 | False | | |
|

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

| 82.78 ns | 91.84 ns | 1.11 | 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.Buffers.Tests.ReadOnlySequenceTests*'
```

### System.Buffers.Tests.ReadOnlySequenceTests<Char>.SliceArray

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Buffers.Tests.ReadOnlySequenceTests<Char>.IterateForEachSingleSegment

#### 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 entries in src/benchmarks/micro/libraries/System.Buffers/ReadOnlySequenceTests.cs at lines 89-90 and 111-113, then run the provided benchmarks_ci.py reproduction. Compare the baseline and compare commits and the linked test report; done means determining and addressing the regression so both benchmarks no longer show the reported slowdown.

Written by the indexing model from the issue text.