[Perf] Linux/x64: 1 Regression on 6/18/2026 7:52:57 AM +00:00

### Run Information

Name | Value
-- | --
Architecture | x64
OS | ubuntu 22.04
Queue | ViperUbuntu
Baseline | [d72d2fcf29301c5f9fe2c7188c90df93b0730989](https://github.com/dotnet/runtime/commit/d72d2fcf29301c5f9fe2c7188c90df93b0730989)
Compare | [a17debec450d73f9d84e68ca44f63b217f5db49f](https://github.com/dotnet/runtime/commit/a17debec450d73f9d84e68ca44f63b217f5db49f)
Diff | [Diff](https://github.com/dotnet/runtime/compare/d72d2fcf29301c5f9fe2c7188c90df93b0730989...a17debec450d73f9d84e68ca44f63b217f5db49f)
Configs | CompilationMode:wasm, RunKind:micro, RuntimeType:coreclr

### Regressions in System.IO.Tests.Perf_FileStream

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

• [Write_NoBuffering - 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
python3 .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.IO.Tests.Perf_FileStream*'
```

### System.IO.Tests.Perf_FileStream.Write_NoBuffering(fileSize: 104857600, userBufferSize: 16384, options: Asynchronous)

#### 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 linked benchmark source, performance/src/benchmarks/micro/libraries/System.IO.FileSystem/Perf.FileStream.cs, and reproduce System.IO.Tests.Perf_FileStream with the provided benchmarks_ci.py command. Compare the reported baseline and test results for Write_NoBuffering, then use the profiling and benchmarking workflow documents to investigate the regression; done means identifying and addressing its cause.

Written by the indexing model from the issue text.