[Perf] Linux/arm64: 2 Improvements on 6/23/2026 8:41:58 PM +00:00

### Run Information

Name | Value
-- | --
Architecture | arm64
OS | azurelinux 3.0
Queue | CobaltAzureLinux
Baseline | [e3ecd30e4d6bfeedec6b4730c8ef87951cfe1f17](https://github.com/dotnet/runtime/commit/e3ecd30e4d6bfeedec6b4730c8ef87951cfe1f17)
Compare | [feb1fe23e41b7af2401edbd4230bf11dcb9cfc96](https://github.com/dotnet/runtime/commit/feb1fe23e41b7af2401edbd4230bf11dcb9cfc96)
Diff | [Diff](https://github.com/dotnet/runtime/compare/e3ecd30e4d6bfeedec6b4730c8ef87951cfe1f17...feb1fe23e41b7af2401edbd4230bf11dcb9cfc96)
Configs | CompilationMode:tiered, RunKind:micro

### Improvements in System.Collections.Tests.Perf_Dictionary

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

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

| 14.04 μs | 12.10 μs | 0.86 | 0.17 | 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.Tests.Perf_Dictionary*'
```

### System.Collections.Tests.Perf_Dictionary.Clone(Items: 3000)

#### 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 | arm64
OS | azurelinux 3.0
Queue | CobaltAzureLinux
Baseline | [e3ecd30e4d6bfeedec6b4730c8ef87951cfe1f17](https://github.com/dotnet/runtime/commit/e3ecd30e4d6bfeedec6b4730c8ef87951cfe1f17)
Compare | [feb1fe23e41b7af2401edbd4230bf11dcb9cfc96](https://github.com/dotnet/runtime/commit/feb1fe23e41b7af2401edbd4230bf11dcb9cfc96)
Diff | [Diff](https://github.com/dotnet/runtime/compare/e3ecd30e4d6bfeedec6b4730c8ef87951cfe1f17...feb1fe23e41b7af2401edbd4230bf11dcb9cfc96)
Configs | CompilationMode:tiered, RunKind:micro

### Improvements in System.Collections.CtorFromCollection<Int32>

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

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

| 2.56 μs | 2.22 μs | 0.87 | 0.30 | 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<Int32>.Dictionary(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 src/benchmarks/micro/libraries/System.Collections/Dictionary/Perf_Dictionary.cs and src/benchmarks/micro/libraries/System.Collections/Create/CtorFromCollection.cs at the linked lines. Reproduce both filters with benchmarks_ci.py, then compare the baseline and test reports for the Linux/arm64 run. Done means identifying whether the reported improvements require follow-up or can be closed as expected behavior.

Written by the indexing model from the issue text.