Regressions in System.Memory.ReadOnlySpan

### Run Information

Architecture | x64
-- | --
OS | Windows 10.0.18362
Baseline | [6aaee1622b87d8a8d1cf38c235e9c37f2c622df1](https://github.com/dotnet/runtime/commit/6aaee1622b87d8a8d1cf38c235e9c37f2c622df1)
Compare | [1e48eca9577433526c5c649a87ca2f2545d35958](https://github.com/dotnet/runtime/commit/1e48eca9577433526c5c649a87ca2f2545d35958)
Diff | [Diff](https://github.com/dotnet/runtime/compare/6aaee1622b87d8a8d1cf38c235e9c37f2c622df1...1e48eca9577433526c5c649a87ca2f2545d35958)


### Regressions in System.Memory.ReadOnlySpan

Benchmark | Baseline | Test | Test/Base | Test Quality | Edge Detector | Baseline IR | Compare IR | IR Ratio | Baseline ETL | Compare ETL
-- | -- | -- | -- | -- | -- | -- | -- | -- | -- | --
[IndexOfString - Duration of single invocation](<https://pvscmdupload.blob.core.windows.net/reports/allTestHistory/refs/heads/main_x64_Windows 10.0.18362/System.Memory.ReadOnlySpan.IndexOfString(input%3a%20%22AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAXAAAAAAAAAAAAAAAAAAAAAAAAAAAAA%22%2c%20value%3a%20%22x%22%2c%20comparisonType%3a%20OrdinalIgnoreCase).html>) | 217.46 ns | 238.56 ns | 1.10 | 0.03 | False | | |

![graph](<https://pvscmdupload.blob.core.windows.net/autofilereport/autofilereports/11_09_2021/refs/heads/main_x64_Windows%2010.0.18362_Regression/System.Memory.ReadOnlySpan_1.png>)
[Test Report](<https://pvscmdupload.blob.core.windows.net/autofilereport/autofilereports/11_09_2021/refs/heads/main_x64_Windows%2010.0.18362_Regression/System.Memory.ReadOnlySpan.html>)

### Repro

```cmd
git clone https://github.com/dotnet/performance.git
py .\performance\scripts\benchmarks_ci.py -f net6.0 --filter 'System.Memory.ReadOnlySpan*'
```
<details>

### Payloads

[Baseline](<https://helixdi8s23ayyeko0k025g8.blob.core.windows.net/helix-job-f66b7184-14f2-41c6-ad07-97f7f31772dcfdee065eefd491cbb/d0a1ff5e-09de-4e01-9f8d-37d56d663dc0.zip?sv=2019-07-07&se=2021-12-03T12%3A26%3A08Z&sr=c&sp=rl&sig=9mDvAObzIF1n8OW1NGxxGEBKwa%2FNBPL0bWZwJQ85OqI%3D>)
[Compare](<https://helixdi8s23ayyeko0k025g8.blob.core.windows.net/helix-job-d7d5f257-09ec-4151-8ea8-10c61d623bb42c96cb913414f8b9f/d4a7cd2f-7efd-49bb-98d5-14bab5ed5399.zip?sv=2019-07-07&se=2021-12-04T01%3A14%3A00Z&sr=c&sp=rl&sig=xA8zjoN69FRaBpXoe%2BMJHb%2BlMybCXvFvnhYIe6fQ4uw%3D>)
### Histogram

#### System.Memory.ReadOnlySpan.IndexOfString(input: "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAXAAAAAAAAAAAAAAAAAAAAAAAAAAAAA", value: "x", comparisonType: OrdinalIgnoreCase)

```log

```


### 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)

</details>


Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Regressions in System.Memory.ReadOnlySpan #61679

Run Information