[Perf] Linux/x64: 4 Improvements on 8/7/2026 3:11:20 AM +00:00

### Run Information

Name | Value
-- | --
Architecture | x64
OS | ubuntu 22.04
Queue | ViperUbuntu
Baseline | [55fba988b198b5d36d3adae189b4ab1d1420cf7c](https://github.com/dotnet/runtime/commit/55fba988b198b5d36d3adae189b4ab1d1420cf7c)
Compare | [45fb46d810550207fe12a2b02dabec25f47c71ad](https://github.com/dotnet/runtime/commit/45fb46d810550207fe12a2b02dabec25f47c71ad)
Diff | [Diff](https://github.com/dotnet/runtime/compare/55fba988b198b5d36d3adae189b4ab1d1420cf7c...45fb46d810550207fe12a2b02dabec25f47c71ad)
Configs | CompilationMode:wasm, RunKind:micro, RuntimeType:coreclr

### Improvements 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]()

| 30.31 ms | 21.47 ms | 0.71 | 0.34 | False | | |
|

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

| 4.58 μs | 3.98 μs | 0.87 | 0.29 | 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.Collections.CtorFromCollection*'
```

### System.Collections.CtorFromCollection<String>.ImmutableSortedDictionary(Size: 512)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Collections.CtorFromCollection<String>.Stack(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 | x64
OS | ubuntu 22.04
Queue | ViperUbuntu
Baseline | [55fba988b198b5d36d3adae189b4ab1d1420cf7c](https://github.com/dotnet/runtime/commit/55fba988b198b5d36d3adae189b4ab1d1420cf7c)
Compare | [45fb46d810550207fe12a2b02dabec25f47c71ad](https://github.com/dotnet/runtime/commit/45fb46d810550207fe12a2b02dabec25f47c71ad)
Diff | [Diff](https://github.com/dotnet/runtime/compare/55fba988b198b5d36d3adae189b4ab1d1420cf7c...45fb46d810550207fe12a2b02dabec25f47c71ad)
Configs | CompilationMode:wasm, RunKind:micro, RuntimeType:coreclr

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

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

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

| 2.18 μs | 1.84 μs | 0.85 | 0.29 | 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 'System.Memory.Span*'
```

### System.Memory.Span<Byte>.CopyTo(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 | x64
OS | ubuntu 22.04
Queue | ViperUbuntu
Baseline | [55fba988b198b5d36d3adae189b4ab1d1420cf7c](https://github.com/dotnet/runtime/commit/55fba988b198b5d36d3adae189b4ab1d1420cf7c)
Compare | [45fb46d810550207fe12a2b02dabec25f47c71ad](https://github.com/dotnet/runtime/commit/45fb46d810550207fe12a2b02dabec25f47c71ad)
Diff | [Diff](https://github.com/dotnet/runtime/compare/55fba988b198b5d36d3adae189b4ab1d1420cf7c...45fb46d810550207fe12a2b02dabec25f47c71ad)
Configs | CompilationMode:wasm, RunKind:micro, RuntimeType:coreclr

### Improvements in System.Collections.IterateFor<String>

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

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

| 1.34 ms | 1.15 ms | 0.86 | 0.29 | 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 'System.Collections.IterateFor*'
```

### System.Collections.IterateFor<String>.IList(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 named in the report: src/benchmarks/micro/libraries/System.Collections/Create/CtorFromCollection.cs, System.Memory/Span.cs, and System.Collections/Iterate/IterateFor.cs. Run the provided benchmarks_ci.py filters, then compare the baseline and test reports for the listed WASM improvements. Done means the cause and an appropriate runtime change are identified and validated against the affected benchmarks.

Written by the indexing model from the issue text.