[Perf] Windows/x64: 4 Improvements on 9/13/2026 2:59:42 PM +00:00

### Run Information

Name | Value
-- | --
Architecture | x64
OS | Windows 10.0.22631
Queue | ViperWindows
Baseline | [6ed2ba318dcaa936da60f7d6bc9eb30cad54fc0c](https://github.com/dotnet/runtime/commit/6ed2ba318dcaa936da60f7d6bc9eb30cad54fc0c)
Compare | [edd70ca597f37a95a3ccc04c127fb8e883cc4139](https://github.com/dotnet/runtime/commit/edd70ca597f37a95a3ccc04c127fb8e883cc4139)
Diff | [Diff](https://github.com/dotnet/runtime/compare/6ed2ba318dcaa936da60f7d6bc9eb30cad54fc0c...edd70ca597f37a95a3ccc04c127fb8e883cc4139)
Configs | CompilationMode:tiered, RunKind:micro

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

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

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

| 39.18 ns | 27.93 ns | 0.71 | 0.31 | False | | |
|

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

| 4.87 ns | 3.52 ns | 0.72 | 0.00 | False | | |
|

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

| 5.42 ns | 4.06 ns | 0.75 | 0.01 | False | | |
|

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

| 8.40 ns | 7.31 ns | 0.87 | 0.19 | False | | |

![graph]()
![graph]()
![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.Memory.Span*'
```

### System.Memory.Span<Char>.IndexOfValue(Size: 3000)

#### ETL Files

#### Histogram

#### JIT Disasms

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

#### ETL Files

#### Histogram

#### JIT Disasms

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

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Memory.Span<Char>.IndexOfValue(Size: 512)

#### 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 performance/src/benchmarks/micro/libraries/System.Memory/Span.cs lines 74-75 and 88-89, then review the linked System.Memory.Span test report. Run the provided benchmarks_ci.py command to reproduce the Windows/x64 results. Done would require identifying an actionable runtime performance change and validating it against these benchmarks, but the issue does not specify a target change.

Written by the indexing model from the issue text.