[Perf] Linux/x64: 1 Improvement on 8/18/2026 6:23:40 PM +00:00

### Run Information

Name | Value
-- | --
Architecture | x64
OS | ubuntu 22.04
Queue | ViperUbuntu
Baseline | [66301852b657d335afd90dfc388450676a3084a8](https://github.com/dotnet/runtime/commit/66301852b657d335afd90dfc388450676a3084a8)
Compare | [029a98f26a9506810140781e88ccb8e45de1cc79](https://github.com/dotnet/runtime/commit/029a98f26a9506810140781e88ccb8e45de1cc79)
Diff | [Diff](https://github.com/dotnet/runtime/compare/66301852b657d335afd90dfc388450676a3084a8...029a98f26a9506810140781e88ccb8e45de1cc79)
Configs | AOT:true, CompilationMode:wasm, RunKind:micro

### Improvements in System.Tests.Perf_Int128

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

• [ParseSpan - 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_Int128*'
```

### System.Tests.Perf_Int128.ParseSpan(value: "-170141183460469231731687303715884105728")

#### 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 src/benchmarks/micro/libraries/System.Runtime/Perf.Int128.cs lines 43-45 and reproduce System.Tests.Perf_Int128.ParseSpan using the benchmarks_ci.py command in the issue. Compare the baseline and test commits and inspect the linked benchmark report; done means identifying and addressing the cause of the reported performance change, with the benchmark confirming the result.

Written by the indexing model from the issue text.