dotnet / dotnet/perf-autofiling-issues

[Perf] Linux/x64: 6 Regressions on 8/14/2026 4:30:00 PM +00:00

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arch-wasm arch-x64 branch-refs/heads/main compilationmode-wasm kind-micro Look Again os-linux perf-regression runkind-micro runtimetype-coreclr untriaged
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Description

### Run Information

Name | Value
-- | --
Architecture | x64
OS | ubuntu 22.04
Queue | ViperUbuntu
Baseline | [691fd960eb500743b4be71373b11b2263bdbc318](https://github.com/dotnet/runtime/commit/691fd960eb500743b4be71373b11b2263bdbc318)
Compare | [6276bd4a23e9e21597ccccba91f908917bc8e189](https://github.com/dotnet/runtime/commit/6276bd4a23e9e21597ccccba91f908917bc8e189)
Diff | [Diff](https://github.com/dotnet/runtime/compare/691fd960eb500743b4be71373b11b2263bdbc318...6276bd4a23e9e21597ccccba91f908917bc8e189)
Configs | CompilationMode:wasm, RunKind:micro, RuntimeType:coreclr

### Regressions in System.Collections.TryGetValueTrue<SmallClass, SmallClass>

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]()
| 7.87 ms | 13.78 ms | 1.75 | 0.26 | False | | |
|
  • [ConcurrentDictionary - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 1.01 ms | 1.59 ms | 1.58 | 0.28 | False | | |
|
  • [ImmutableDictionary - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 2.08 ms | 3.02 ms | 1.45 | 0.23 | False | | |

![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
python3 .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Collections.TryGetValueTrue*'
```

### System.Collections.TryGetValueTrue<SmallClass, SmallClass>.ImmutableSortedDictionary(Size: 512)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Collections.TryGetValueTrue<SmallClass, SmallClass>.ConcurrentDictionary(Size: 512)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Collections.TryGetValueTrue<SmallClass, SmallClass>.ImmutableDictionary(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 | [691fd960eb500743b4be71373b11b2263bdbc318](https://github.com/dotnet/runtime/commit/691fd960eb500743b4be71373b11b2263bdbc318)
Compare | [6276bd4a23e9e21597ccccba91f908917bc8e189](https://github.com/dotnet/runtime/commit/6276bd4a23e9e21597ccccba91f908917bc8e189)
Diff | [Diff](https://github.com/dotnet/runtime/compare/691fd960eb500743b4be71373b11b2263bdbc318...6276bd4a23e9e21597ccccba91f908917bc8e189)
Configs | CompilationMode:wasm, RunKind:micro, RuntimeType:coreclr

### Regressions in PerfLabTests.CastingPerf

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

  • [CheckArrayIsInterfaceYes - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 58.92 ms | 104.99 ms | 1.78 | 0.21 | 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 'PerfLabTests.CastingPerf*'
```

### PerfLabTests.CastingPerf.CheckArrayIsInterfaceYes

#### 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 | [d00a0a24912957046ed2443adc0af7bbfb4c43bc](https://github.com/dotnet/runtime/commit/d00a0a24912957046ed2443adc0af7bbfb4c43bc)
Compare | [6276bd4a23e9e21597ccccba91f908917bc8e189](https://github.com/dotnet/runtime/commit/6276bd4a23e9e21597ccccba91f908917bc8e189)
Diff | [Diff](https://github.com/dotnet/runtime/compare/d00a0a24912957046ed2443adc0af7bbfb4c43bc...6276bd4a23e9e21597ccccba91f908917bc8e189)
Configs | CompilationMode:wasm, RunKind:micro, RuntimeType:coreclr

### Regressions in System.Collections.Perf_SubstringFrozenDictionary

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

  • [ToFrozenDictionary - Duration of single invocation]()
  • [ADX - Test Multi Config Graph]()
| 73.67 ms | 104.21 ms | 1.41 | 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
python3 .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Collections.Perf_SubstringFrozenDictionary*'
```

### System.Collections.Perf_SubstringFrozenDictionary.ToFrozenDictionary(Count: 10000)

#### 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 | [d00a0a24912957046ed2443adc0af7bbfb4c43bc](https://github.com/dotnet/runtime/commit/d00a0a24912957046ed2443adc0af7bbfb4c43bc)
Compare | [6276bd4a23e9e21597ccccba91f908917bc8e189](https://github.com/dotnet/runtime/commit/6276bd4a23e9e21597ccccba91f908917bc8e189)
Diff | [Diff](https://github.com/dotnet/runtime/compare/d00a0a24912957046ed2443adc0af7bbfb4c43bc...6276bd4a23e9e21597ccccba91f908917bc8e189)
Configs | CompilationMode:wasm, RunKind:micro, RuntimeType:coreclr

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

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

  • [Array - Duration of single invocation]()
  • 📝 - [Benchmark Source]()
  • [ADX - Test Multi Config Graph]()
| 5.64 ms | 6.92 ms | 1.23 | 0.22 | 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.Sort*'
```

### System.Collections.Sort<IntClass>.Array(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)

Contributor guide

No contributing guide indexed for this repository

Research direction

Start with the benchmark command in the Repro section and the linked benchmarking workflow documentation. Inspect the named sources, including src/benchmarks/micro/libraries/System.Collections/TryGetValue/TryGetValueTrue.cs and src/benchmarks/micro/runtime/perflab/CastingPerf.cs, then compare the baseline and test reports and commits. Done means determining the cause of the reported regressions and providing a verified result for the affected benchmarks.

Written by the indexing model from the issue text.

Assessment

Tech stack
csharp, python, ubuntu, wasm
Domain
performance, testing, tooling
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Active
Clarity
Mostly clear
Newbie friendliness
48/100

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