[Perf] Linux/x64: 1 Regression on 4/12/2026 7:42:22 PM +00:00

### Run Information

Name | Value
-- | --
Architecture | x64
OS | ubuntu 22.04
Queue | ViperUbuntu
Baseline | [c62c41f71a527b2d450e57782182e68ae169ba33](https://github.com/dotnet/runtime/commit/c62c41f71a527b2d450e57782182e68ae169ba33)
Compare | [fe15cb280012d02b4c83388bf30bd757c23d97b2](https://github.com/dotnet/runtime/commit/fe15cb280012d02b4c83388bf30bd757c23d97b2)
Diff | [Diff](https://github.com/dotnet/runtime/compare/c62c41f71a527b2d450e57782182e68ae169ba33...fe15cb280012d02b4c83388bf30bd757c23d97b2)
Configs | CompilationMode:wasm, RunKind:micro

### Regressions in System.IO.Tests.Perf_RandomAccess

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

• [Read - Duration of single invocation]()
• 📝 - [Benchmark Source]()
• [ADX - Test Multi Config 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_RandomAccess*'
```

### System.IO.Tests.Perf_RandomAccess.Read(fileSize: 104857600, bufferSize: 16384, options: None)

#### 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 performance/src/benchmarks/micro/libraries/System.IO.FileSystem/Perf.RandomAccess.cs#L76-L92 and the provided benchmarking workflow. Reproduce System.IO.Tests.Perf_RandomAccess.Read with the wasm configuration, then compare the baseline and test commits to isolate the regression. Done means the performance change is explained and a verified correction removes the reported regression.

Written by the indexing model from the issue text.