[Perf] Linux/x64: 2 Regressions on 8/25/2026 5:23:38 PM +00:00

### Run Information

Name | Value
-- | --
Architecture | x64
OS | ubuntu 22.04
Queue | ViperUbuntu
Baseline | [df846d69e1666f9c6060f2487975b568f3ed93bb](https://github.com/dotnet/runtime/commit/df846d69e1666f9c6060f2487975b568f3ed93bb)
Compare | [cd254340926a9de135f596224d5d4daff12c2395](https://github.com/dotnet/runtime/commit/cd254340926a9de135f596224d5d4daff12c2395)
Diff | [Diff](https://github.com/dotnet/runtime/compare/df846d69e1666f9c6060f2487975b568f3ed93bb...cd254340926a9de135f596224d5d4daff12c2395)
Configs | AOT:true, CompilationMode:wasm, RunKind:micro

### Regressions in System.Text.Json.Tests.Perf_Get

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

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

| 7.11 μs | 8.55 μs | 1.20 | 0.03 | False | | |
|

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

| 7.00 μs | 8.39 μs | 1.20 | 0.04 | 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.Text.Json.Tests.Perf_Get*'
```

### System.Text.Json.Tests.Perf_Get.GetSingle

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Text.Json.Tests.Perf_Get.GetDouble

#### 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 source at performance/src/benchmarks/micro/libraries/System.Text.Json/Utf8JsonReader/Perf.Get.cs lines 161-188 and reproduce with the provided benchmarks_ci.py command. Compare the baseline and test commits and inspect the linked performance reports for GetSingle and GetDouble. Done means identifying and resolving the regression while preserving the benchmark results.

Written by the indexing model from the issue text.