[Perf] Linux/x64: 2 Regressions on 8/4/2026 3:42:07 PM +00:00

### Run Information

Name | Value
-- | --
Architecture | x64
OS | ubuntu 22.04
Queue | ViperUbuntu
Baseline | [80aa3f8c5a2d33664fbedafd2f2bb18fdeb8002f](https://github.com/dotnet/runtime/commit/80aa3f8c5a2d33664fbedafd2f2bb18fdeb8002f)
Compare | [f107b2325cccfd453f9bf46013159f4704ea56c2](https://github.com/dotnet/runtime/commit/f107b2325cccfd453f9bf46013159f4704ea56c2)
Diff | [Diff](https://github.com/dotnet/runtime/compare/80aa3f8c5a2d33664fbedafd2f2bb18fdeb8002f...f107b2325cccfd453f9bf46013159f4704ea56c2)
Configs | CompilationMode:wasm, RunKind:micro

### Regressions in System.Tests.Perf_Double

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

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

| 502.39 μs | 534.28 μs | 1.06 | 0.02 | False | | |
|

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

| 502.24 μs | 531.47 μs | 1.06 | 0.01 | 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.Tests.Perf_Double*'
```

### System.Tests.Perf_Double.ToStringWithFormat(value: -1.7976931348623157E+308, format: "F50")

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Tests.Perf_Double.ToStringWithFormat(value: 1.7976931348623157E+308, format: "F50")

#### 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.Runtime/Perf.Double.cs#L65-L69 and compare the listed baseline and comparison commits. Run the provided benchmarks_ci.py command for System.Tests.Perf_Double, then inspect the linked test report and graphs. Done means the cause of the two wasm performance regressions is identified and the affected benchmarks no longer regress.

Written by the indexing model from the issue text.