[Perf] Linux/x64: 3 Regressions on 1/20/2026 3:13:09 AM +00:00

### Run Information

Name | Value
-- | --
Architecture | x64
OS | ubuntu 22.04
Queue | TigerUbuntu
Baseline | [de88fe799ce9f061dcf33dc54292cf1c41700434](https://github.com/dotnet/runtime/commit/de88fe799ce9f061dcf33dc54292cf1c41700434)
Compare | [de91bb5034d88c9205096f9c43b05d03b3f62d11](https://github.com/dotnet/runtime/commit/de91bb5034d88c9205096f9c43b05d03b3f62d11)
Diff | [Diff](https://github.com/dotnet/runtime/compare/de88fe799ce9f061dcf33dc54292cf1c41700434...de91bb5034d88c9205096f9c43b05d03b3f62d11)
Configs | CompilationMode:tiered, RunKind:micro

### Regressions in System.Memory.Span<Char>

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

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

| 1.60 ns | 2.71 ns | 1.70 | 0.05 | False | | |
|

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

| 1.62 ns | 3.03 ns | 1.87 | 0.08 | 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.Memory.Span*'
```

### System.Memory.Span<Char>.Reverse(Size: 4)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Memory.Span<Char>.Reverse(Size: 33)

#### 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)

---

### Run Information

Name | Value
-- | --
Architecture | x64
OS | ubuntu 22.04
Queue | TigerUbuntu
Baseline | [420d1efe11c29c8e8b9a6346ca6c3676750e8498](https://github.com/dotnet/runtime/commit/420d1efe11c29c8e8b9a6346ca6c3676750e8498)
Compare | [de91bb5034d88c9205096f9c43b05d03b3f62d11](https://github.com/dotnet/runtime/commit/de91bb5034d88c9205096f9c43b05d03b3f62d11)
Diff | [Diff](https://github.com/dotnet/runtime/compare/420d1efe11c29c8e8b9a6346ca6c3676750e8498...de91bb5034d88c9205096f9c43b05d03b3f62d11)
Configs | CompilationMode:tiered, RunKind:micro

### Regressions in Benchstone.MDBenchI.MDGeneralArray

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

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

| 11.91 ms | 14.76 ms | 1.24 | 0.52 | False | | |

![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 'Benchstone.MDBenchI.MDGeneralArray*'
```

### Benchstone.MDBenchI.MDGeneralArray.Test

#### 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)