[Perf] Windows/x64: 1 Improvement on 7/19/2026 9:49:55 PM +00:00

### Run Information

Name | Value
-- | --
Architecture | x64
OS | Windows 10.0.22631
Queue | ViperWindows
Baseline | [c536338d89a6ccc0bcbca46e44e3343d990e06aa](https://github.com/dotnet/runtime/commit/c536338d89a6ccc0bcbca46e44e3343d990e06aa)
Compare | [563abf220847ed66cab58f0d7d166cb264874f40](https://github.com/dotnet/runtime/commit/563abf220847ed66cab58f0d7d166cb264874f40)
Diff | [Diff](https://github.com/dotnet/runtime/compare/c536338d89a6ccc0bcbca46e44e3343d990e06aa...563abf220847ed66cab58f0d7d166cb264874f40)
Configs | CompilationMode:tiered, RunKind:micro

### Improvements in System.Text.RegularExpressions.Tests.Perf_Regex_Cache

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

• [IsMatch_Multithreading - 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
py .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Text.RegularExpressions.Tests.Perf_Regex_Cache*'
```

### System.Text.RegularExpressions.Tests.Perf_Regex_Cache.IsMatch_Multithreading(total: 40000, unique: 7, cacheSize: 0)

#### 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.Text.RegularExpressions/Perf.Regex.Cache.cs#L63-L89 and review the linked performance report for IsMatch_Multithreading. Run the provided benchmarks_ci.py command to reproduce the comparison; done requires identifying and validating the cause of the reported performance difference.

Written by the indexing model from the issue text.