[Perf] Linux/x64: 5 Improvements on 8/21/2026 2:45:13 AM +00:00

### Run Information

Name | Value
-- | --
Architecture | x64
OS | ubuntu 22.04
Queue | ViperUbuntu
Baseline | [be1c680101458a735200e68a74460919be249315](https://github.com/dotnet/runtime/commit/be1c680101458a735200e68a74460919be249315)
Compare | [76c60b960a2daa412c44a5061abf66f3286f6a92](https://github.com/dotnet/runtime/commit/76c60b960a2daa412c44a5061abf66f3286f6a92)
Diff | [Diff](https://github.com/dotnet/runtime/compare/be1c680101458a735200e68a74460919be249315...76c60b960a2daa412c44a5061abf66f3286f6a92)
Configs | CompilationMode:tiered, RunKind:micro

### Improvements in System.Buffers.Text.Tests.Base64Tests

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

• [Base64Decode - Duration of single invocation]()
• 📝 - [Benchmark Source]()
• [ADX - Test Multi Config Graph]()

| 37.16 ns | 23.54 ns | 0.63 | 0.19 | False | | |
|

• [Base64EncodeDestinationTooSmall - Duration of single invocation]()
• 📝 - [Benchmark Source]()
• [ADX - Test Multi Config Graph]()

| 30.23 ns | 25.76 ns | 0.85 | 0.36 | 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.Buffers.Text.Tests.Base64Tests*'
```

### System.Buffers.Text.Tests.Base64Tests.Base64Decode(NumberOfBytes: 1000)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Buffers.Text.Tests.Base64Tests.Base64EncodeDestinationTooSmall(NumberOfBytes: 1000)

#### 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 | [be1c680101458a735200e68a74460919be249315](https://github.com/dotnet/runtime/commit/be1c680101458a735200e68a74460919be249315)
Compare | [76c60b960a2daa412c44a5061abf66f3286f6a92](https://github.com/dotnet/runtime/commit/76c60b960a2daa412c44a5061abf66f3286f6a92)
Diff | [Diff](https://github.com/dotnet/runtime/compare/be1c680101458a735200e68a74460919be249315...76c60b960a2daa412c44a5061abf66f3286f6a92)
Configs | CompilationMode:tiered, RunKind:micro

### Improvements in System.Text.Perf_Ascii

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

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

| 14.85 ns | 13.23 ns | 0.89 | 0.03 | False | | |
|

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

| 14.42 ns | 13.23 ns | 0.92 | 0.05 | 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.Perf_Ascii*'
```

### System.Text.Perf_Ascii.ToUpper_Chars(Size: 128)

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Text.Perf_Ascii.ToLower_Chars(Size: 128)

#### 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 | [be1c680101458a735200e68a74460919be249315](https://github.com/dotnet/runtime/commit/be1c680101458a735200e68a74460919be249315)
Compare | [76c60b960a2daa412c44a5061abf66f3286f6a92](https://github.com/dotnet/runtime/commit/76c60b960a2daa412c44a5061abf66f3286f6a92)
Diff | [Diff](https://github.com/dotnet/runtime/compare/be1c680101458a735200e68a74460919be249315...76c60b960a2daa412c44a5061abf66f3286f6a92)
Configs | CompilationMode:tiered, RunKind:micro

### Improvements in System.Text.Json.Tests.Perf_Base64

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

• [WriteByteArrayAsBase64_NoEscaping - Duration of single invocation]()
• 📝 - [Benchmark Source]()
• [ADX - Test Multi Config Graph]()

| 69.49 ns | 64.60 ns | 0.93 | 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
python3 .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Text.Json.Tests.Perf_Base64*'
```

### System.Text.Json.Tests.Perf_Base64.WriteByteArrayAsBase64_NoEscaping(NumberOfBytes: 1000)

#### 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 linked benchmark sources: src/benchmarks/micro/libraries/System.Buffers/Base64Tests.cs, System.Text.Encoding/Perf.Ascii.cs, and System.Text.Json/Utf8JsonWriter/Perf.Base64.cs. Run the provided benchmarks_ci.py filters and inspect the linked reports and baseline/compare commits; done means determining whether the measured improvements need runtime follow-up.

Written by the indexing model from the issue text.