[Perf] Linux/x64: 1 Regression on 7/21/2026 10:06:44 PM +00:00

### Run Information

Name | Value
-- | --
Architecture | x64
OS | ubuntu 22.04
Queue | ViperUbuntu
Baseline | [7e3626903d758fab196fa09782a7e198a985bf36](https://github.com/dotnet/runtime/commit/7e3626903d758fab196fa09782a7e198a985bf36)
Compare | [56c76e2f3594e2b6208c8bf61f5dda0eb476e353](https://github.com/dotnet/runtime/commit/56c76e2f3594e2b6208c8bf61f5dda0eb476e353)
Diff | [Diff](https://github.com/dotnet/runtime/compare/7e3626903d758fab196fa09782a7e198a985bf36...56c76e2f3594e2b6208c8bf61f5dda0eb476e353)
Configs | AOT:true, CompilationMode:wasm, RunKind:micro

### Regressions in System.Tests.Perf_Int64

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

• [ToString - 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.Tests.Perf_Int64*'
```

### System.Tests.Perf_Int64.ToString(value: 12345)

#### 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 baseline-to-compare commit diff and the benchmark source at src/benchmarks/micro/libraries/System.Runtime/Perf.Int64.cs#L26-L28. Reproduce System.Tests.Perf_Int64.ToString(value: 12345) using the provided benchmarks_ci.py command and inspect the linked test report for the Linux/x64 WebAssembly AOT run. Done means identifying the regression and restoring the benchmark result.

Written by the indexing model from the issue text.