[Perf] Linux/x64: 6 Regressions on 8/19/2026 11:48:00 PM +00:00

### Run Information

Name | Value
-- | --
Architecture | x64
OS | ubuntu 22.04
Queue | ViperUbuntu
Baseline | [22645b47c400e6cc0aec97ddcb3f1998677b6d94](https://github.com/dotnet/runtime/commit/22645b47c400e6cc0aec97ddcb3f1998677b6d94)
Compare | [cb8ddc8cac0182e932903d921bd09300be7ae2a6](https://github.com/dotnet/runtime/commit/cb8ddc8cac0182e932903d921bd09300be7ae2a6)
Diff | [Diff](https://github.com/dotnet/runtime/compare/22645b47c400e6cc0aec97ddcb3f1998677b6d94...cb8ddc8cac0182e932903d921bd09300be7ae2a6)
Configs | AOT:true, CompilationMode:wasm, RunKind:micro

### Regressions in System.Numerics.Tests.Perf_BigInteger

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

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

| 67.12 μs | 90.52 μs | 1.35 | 0.34 | False | | |
|

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

| 1.05 ms | 1.30 ms | 1.24 | 0.08 | False | | |
|

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

| 18.95 ns | 23.25 ns | 1.23 | 0.14 | False | | |
|

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

| 4.38 μs | 5.36 μs | 1.22 | 0.05 | False | | |

![graph]()
![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.Numerics.Tests.Perf_BigInteger*'
```

### System.Numerics.Tests.Perf_BigInteger.ModPow(arguments: 1024,1024,64 bits)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Numerics.Tests.Perf_BigInteger.ModPow(arguments: 16384,16384,64 bits)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Numerics.Tests.Perf_BigInteger.Multiply(arguments: 16,8 bits)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Numerics.Tests.Perf_BigInteger.GreatestCommonDivisor(arguments: 1024,1024 bits)

#### 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 | [22645b47c400e6cc0aec97ddcb3f1998677b6d94](https://github.com/dotnet/runtime/commit/22645b47c400e6cc0aec97ddcb3f1998677b6d94)
Compare | [cb8ddc8cac0182e932903d921bd09300be7ae2a6](https://github.com/dotnet/runtime/commit/cb8ddc8cac0182e932903d921bd09300be7ae2a6)
Diff | [Diff](https://github.com/dotnet/runtime/compare/22645b47c400e6cc0aec97ddcb3f1998677b6d94...cb8ddc8cac0182e932903d921bd09300be7ae2a6)
Configs | AOT:true, CompilationMode:wasm, RunKind:micro

### Regressions in System.Tests.Perf_String

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

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

| 1.63 μs | 1.85 μs | 1.14 | 0.12 | False | | |
|

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

| 18.53 ns | 20.35 ns | 1.10 | 0.10 | 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.Tests.Perf_String*'
```

### System.Tests.Perf_String.Format_OneArg(s: "Testing {0}, {0:C}, {0:E} - {0:F4}{0:G}{0:N} , !!", o: 3.14159)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Tests.Perf_String.IndexOfAny

#### 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 at src/benchmarks/micro/libraries/System.Runtime.Numerics/Perf.BigInteger.cs and src/benchmarks/micro/libraries/System.Runtime/Perf.String.cs, then run the provided benchmarks_ci.py command using the reported filter. Compare the baseline and test commits and confirm that the listed regressions are understood and no longer reproduce against the corrected change.

Written by the indexing model from the issue text.