[Perf] Linux/x64: 2 Improvements on 7/28/2026 2:40:15 PM +00:00

### Run Information

Name | Value
-- | --
Architecture | x64
OS | ubuntu 22.04
Queue | ViperUbuntu
Baseline | [00115f085a2df36ea7b135673d290298e20775f7](https://github.com/dotnet/runtime/commit/00115f085a2df36ea7b135673d290298e20775f7)
Compare | [975877333c98d9d08bad66670d74accc6047be34](https://github.com/dotnet/runtime/commit/975877333c98d9d08bad66670d74accc6047be34)
Diff | [Diff](https://github.com/dotnet/runtime/compare/00115f085a2df36ea7b135673d290298e20775f7...975877333c98d9d08bad66670d74accc6047be34)
Configs | CompilationMode:wasm, RunKind:micro, RuntimeType:coreclr

### Improvements in System.Text.Json.Serialization.Tests.ReadJson<StructRecord>

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

• [DeserializeFromUtf8Bytes - Duration of single invocation]()
• 📝 - [Benchmark Source]()
• [ADX - Test Multi Config Graph]()

| 117.96 μs | 93.13 μs | 0.79 | 0.15 | False | | |
|

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

| 139.53 μs | 114.75 μs | 0.82 | 0.15 | 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.Serialization.Tests.ReadJson*'
```

### System.Text.Json.Serialization.Tests.ReadJson<StructRecord>.DeserializeFromUtf8Bytes(Mode: Reflection)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Text.Json.Serialization.Tests.ReadJson<StructRecord>.DeserializeFromString(Mode: Reflection)

#### 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 in performance/src/benchmarks/micro/libraries/System.Text.Json/Serializer/ReadJson.cs at lines 66-72, then run the provided benchmarks_ci.py command. Compare the reported baseline and test results for both deserialization benchmarks, using the linked reports and commits to determine what changed and whether the improvement is reproducible.

Written by the indexing model from the issue text.