[Perf] Windows/x86: 2 Regressions on 6/21/2026 12:45:10 PM +00:00

### Run Information

Name | Value
-- | --
Architecture | x86
OS | Windows 10.0.22631
Queue | ViperWindows
Baseline | [b4ca93f1d026919b29a1000cf520db442cabf61b](https://github.com/dotnet/runtime/commit/b4ca93f1d026919b29a1000cf520db442cabf61b)
Compare | [3b1cc5f2cbbc27d5622c92be222aaeb9c4a819e6](https://github.com/dotnet/runtime/commit/3b1cc5f2cbbc27d5622c92be222aaeb9c4a819e6)
Diff | [Diff](https://github.com/dotnet/runtime/compare/b4ca93f1d026919b29a1000cf520db442cabf61b...3b1cc5f2cbbc27d5622c92be222aaeb9c4a819e6)
Configs | CompilationMode:tiered, RunKind:micro

### Regressions in System.Collections.CtorFromCollection<String>

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

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

| 185.75 μs | 216.61 μs | 1.17 | 0.32 | 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
py .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Collections.CtorFromCollection*'
```

### System.Collections.CtorFromCollection<String>.ImmutableSortedDictionary(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)

---

### Run Information

Name | Value
-- | --
Architecture | x86
OS | Windows 10.0.22631
Queue | ViperWindows
Baseline | [b4ca93f1d026919b29a1000cf520db442cabf61b](https://github.com/dotnet/runtime/commit/b4ca93f1d026919b29a1000cf520db442cabf61b)
Compare | [3b1cc5f2cbbc27d5622c92be222aaeb9c4a819e6](https://github.com/dotnet/runtime/commit/3b1cc5f2cbbc27d5622c92be222aaeb9c4a819e6)
Diff | [Diff](https://github.com/dotnet/runtime/compare/b4ca93f1d026919b29a1000cf520db442cabf61b...3b1cc5f2cbbc27d5622c92be222aaeb9c4a819e6)
Configs | CompilationMode:tiered, RunKind:micro

### Regressions in System.Collections.Sort<String>

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

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

| 175.56 μs | 192.48 μs | 1.10 | 0.28 | 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
py .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Collections.Sort*'
```

### System.Collections.Sort<String>.LinqQuery(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 sources in src/benchmarks/micro/libraries/System.Collections/Create/CtorFromCollection.cs and Sort.cs, then run the provided benchmarks_ci.py filters on Windows x86. Compare commits b4ca93f1d026919b29a1000cf520db442cabf61b and 3b1cc5f2cbbc27d5622c92be222aaeb9c4a819e6 using the linked reports and profiling workflow. Done means the reported regressions are explained and the affected benchmark results no longer regress.

Written by the indexing model from the issue text.