[Perf] Windows/x64: 2 Improvements on 7/5/2026 2:44:21 PM +00:00

### Run Information

Name | Value
-- | --
Architecture | x64
OS | Windows 10.0.22631
Queue | ViperWindows
Baseline | [986fba00d9f89d2dfb8ac440bf37727a18828f64](https://github.com/dotnet/runtime/commit/986fba00d9f89d2dfb8ac440bf37727a18828f64)
Compare | [8f365c934088b8ae21a4dfce8073da0d3eb22a54](https://github.com/dotnet/runtime/commit/8f365c934088b8ae21a4dfce8073da0d3eb22a54)
Diff | [Diff](https://github.com/dotnet/runtime/compare/986fba00d9f89d2dfb8ac440bf37727a18828f64...8f365c934088b8ae21a4dfce8073da0d3eb22a54)
Configs | CompilationMode:tiered, RunKind:micro

### Improvements in System.Tests.Perf_String

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

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

| 4.47 ms | 3.90 ms | 0.87 | 0.09 | False | | |
|

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

| 1001.11 μs | 939.38 μs | 0.94 | 0.03 | 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
py .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Tests.Perf_String*'
```

### System.Tests.Perf_String.Split_Csv(testName: "Short Text", lines: ["Year,quarter,Bene_Geo_Desc,Bene_Mdcd_Mdcr_Enrl_Stus,Bene_Race_Desc,Bene_Sex_Desc,Bene_Mdcr_Entlmt_Stus,Bene_Age_Desc,Bene_RUCA_Desc,Total_Bene_TH_Elig,Total_PartB_Enrl,Total_Bene_Telehealth,Pct_Telehealth", "2020,Overall,National,All,All,All,All,All,All,30946785,32244893.5,14826919,0.4791", "2020,Overall,National,All,All,All,All,All,Rural,7179538,7490300.6667,2858284,0.3981", "2020,Overall,National,All,All,All,All,All,Urban,23696871,24629142.917,11944230,0.504", "2020,Overall,National,All,All,All,All,All,Unknown,,,,", ...])

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Tests.Perf_String.Split_Csv(testName: "Long Numbers", lines: ["StateAbbr,PlaceName,PlaceFIPS,Population2010,ACCESS2_CrudePrev,ACCESS2_Crude95CI,ACCESS2_AdjPrev,ACCESS2_Adj95CI,ARTHRITIS_CrudePrev,ARTHRITIS_Crude95CI,ARTHRITIS_AdjPrev,ARTHRITIS_Adj95CI,BINGE_CrudePrev,BINGE_Crude95CI,BINGE_AdjPrev,BINGE_Adj95CI,BPHIGH_CrudePrev,BPHIGH_Crude95CI,BPHIGH_AdjPrev,BPHIGH_Adj95CI,BPMED_CrudePrev,BPMED_Crude95CI,BPMED_AdjPrev,BPMED_Adj95CI,CANCER_CrudePrev,CANCER_Crude95CI,CANCER_AdjPrev,CANCER_Adj95CI,CASTHMA_CrudePrev,CASTHMA_Crude95CI,CASTHMA_AdjPrev,CASTHMA_Adj95CI,CHD_CrudePrev,CHD_Crude95CI,CHD_AdjPrev,CHD_Adj95CI,CHECKUP_CrudePrev,CHECKUP_Crude95CI,CHECKUP_AdjPrev,CHECKUP_Adj95CI,CHOLSCREEN_CrudePrev,CHOLSCREEN_Crude95CI,CHOLSCREEN_AdjPrev,CHOLSCREEN_Adj95CI,COLON_SCREEN_CrudePrev,COLON_SCREEN_Crude95CI,COLON_SCREEN_AdjPrev,COLON_SCREEN_Adj95CI,COPD_CrudePrev,COPD_Crude95CI,COPD_AdjPrev,COPD_Adj95CI,COREM_CrudePrev,COREM_Crude95CI,COREM_AdjPrev,COREM_Adj95CI,COREW_CrudePrev,COREW_Crude95CI,COREW_AdjPrev,COREW_Adj95CI,CSMOKING_CrudePrev,CSMOKING_Crude95CI,CSMOKING_AdjPrev,CSMOKING_Adj95CI,DENTAL_CrudePrev,DENTAL_Crude95CI,DENTAL_AdjPrev,DENTAL_Adj95CI,DIABETES_CrudePrev,DIABETES_Crude95CI,DIABETES_AdjPrev,DIABETES_Adj95CI,HIGHCHOL_CrudePrev,HIGHCHOL_Crude95CI,HIGHCHOL_AdjPrev,HIGHCHOL_Adj95CI,KIDNEY_CrudePrev,KIDNEY_Crude95CI,KIDNEY_AdjPrev,KIDNEY_Adj95CI,LPA_CrudePrev,LPA_Crude95CI,LPA_AdjPrev,LPA_Adj95CI,MAMMOUSE_CrudePrev,MAMMOUSE_Crude95CI,MAMMOUSE_AdjPrev,MAMMOUSE_Adj95CI,MHLTH_CrudePrev,MHLTH_Crude95CI,MHLTH_AdjPrev,MHLTH_Adj95CI,OBESITY_CrudePrev,OBESITY_Crude95CI,OBESITY_AdjPrev,OBESITY_Adj95CI,PAPTEST_CrudePrev,PAPTEST_Crude95CI,PAPTEST_AdjPrev,PAPTEST_Adj95CI,PHLTH_CrudePrev,PHLTH_Crude95CI,PHLTH_AdjPrev,PHLTH_Adj95CI,SLEEP_CrudePrev,SLEEP_Crude95CI,SLEEP_AdjPrev,SLEEP_Adj95CI,STROKE_CrudePrev,STROKE_Crude95CI,STROKE_AdjPrev,STROKE_Adj95CI,TEETHLOST_CrudePrev,TEETHLOST_Crude95CI,TEETHLOST_AdjPrev,TEETHLOST_Adj95CI,Geolocation", "AL,Birmingham,0107000,212237,20.3,\"(19.9, 20.6)\",20.6,\"(20.2, 21.0)\",29.8,\"(29.6, 29.9)\",29.8,\"(29.6, 29.9)\",11.6,\"(11.5, 11.7)\",11.5,\"(11.4, 11.5)\",44.9,\"(44.7, 45.1)\",45.2,\"(45.0, 45.4)\",79.0,\"(78.9, 79.1)\",67.6,\"(67.6, 67.6)\",5.8,\"( 5.8, 5.8)\",5.8,\"( 5.8, 5.8)\",12.2,\"(12.1, 12.3)\",12.1,\"(12.0, 12.2)\",7.3,\"( 7.2, 7.4)\",7.3,\"( 7.2, 7.3)\",74.9,\"(74.8, 75.0)\",74.9,\"(74.8, 75.0)\",80.2,\"(80.0, 80.4)\",80.9,\"(80.7, 81.1)\",64.1,\"(63.6, 64.5)\",64.7,\"(64.2, 65.1)\",9.3,\"( 9.1, 9.4)\",9.2,\"( 9.1, 9.4)\",32.9,\"(32.2, 33.7)\",33.0,\"(32.2, 33.8)\",26.0,\"(25.4, 26.6)\",26.7,\"(26.1, 27.3)\",21.8,\"(21.4, 22.1)\",22.2,\"(21.8, 22.5)\",52.6,\"(52.1, 53.1)\",52.5,\"(52.0, 53.0)\",16.3,\"(16.1, 16.4)\",16.2,\"(16.1, 16.3)\",34.6,\"(34.5, 34.7)\",31.9,\"(31.9, 31.9)\",4.0,\"( 4.0, 4.1)\",4.0,\"( 4.0, 4.1)\",37.8,\"(37.4, 38.2)\",38.1,\"(37.7, 38.5)\",83.6,\"(83.2, 83.9)\",77.7,\"(77.3, 78.1)\",17.0,\"(16.7, 17.2)\",16.8,\"(16.6, 17.0)\",41.2,\"(41.0, 41.4)\",42.0,\"(41.9, 42.2)\",85.0,\"(84.8, 85.3)\",78.4,\"(78.1, 78.8)\",17.1,\"(16.9, 17.3)\",17.1,\"(16.9, 17.3)\",41.5,\"(41.3, 41.6)\",41.8,\"(41.7, 42.0)\",5.1,\"( 5.0, 5.2)\",5.1,\"( 5.0, 5.1)\",22.8,\"(21.8, 23.9)\",22.9,\"(21.8, 23.9)\",\"(33.52756637730, -86.7988174678)\"", "AL,Hoover,0135896,81619,11.5,\"(11.0, 12.0)\",11.8,\"(11.3, 12.3)\",25.3,\"(25.0, 25.6)\",24.4,\"(24.1, 24.6)\",15.4,\"(15.3, 15.6)\",15.7,\"(15.5, 15.8)\",32.4,\"(32.1, 32.7)\",31.4,\"(31.2, 31.7)\",75.0,\"(74.7, 75.2)\",60.1,\"(60.0, 60.3)\",6.7,\"( 6.6, 6.8)\",6.5,\"( 6.5, 6.6)\",9.2,\"( 9.1, 9.3)\",9.2,\"( 9.1, 9.3)\",4.9,\"( 4.8, 5.0)\",4.7,\"( 4.6, 4.9)\",71.0,\"(70.8, 71.2)\",70.7,\"(70.5, 70.8)\",83.8,\"(83.5, 84.1)\",83.1,\"(82.8, 83.4)\",74.0,\"(73.4, 74.7)\",74.3,\"(73.6, 75.0)\",5.6,\"( 5.3, 5.8)\",5.4,\"( 5.2, 5.6)\",46.3,\"(44.7, 48.0)\",46.8,\"(45.0, 48.5)\",38.6,\"(37.1, 40.0)\",39.3,\"(37.9, 40.7)\",13.4,\"(12.8, 13.9)\",13.2,\"(12.7, 13.8)\",74.5,\"(73.8, 75.2)\",74.5,\"(73.8, 75.1)\",8.4,\"( 8.2, 8.6)\",8.1,\"( 7.9, 8.2)\",33.2,\"(33.0, 33.4)\",30.1,\"(30.0, 30.1)\",2.4,\"( 2.4, 2.5)\",2.4,\"( 2.3, 2.4)\",24.2,\"(23.6, 24.8)\",24.0,\"(23.4, 24.5)\",81.0,\"(80.2, 81.7)\",78.9,\"(78.1, 79.6)\",11.5,\"(11.2, 11.8)\",11.5,\"(11.2, 11.8)\",28.8,\"(28.4, 29.1)\",28.4,\"(28.1, 28.7)\",85.5,\"(85.0, 86.0)\",83.5,\"(83.0, 84.0)\",10.6,\"(10.3, 10.9)\",10.2,\"(10.0, 10.5)\",32.9,\"(32.6, 33.3)\",32.8,\"(32.5, 33.2)\",2.4,\"( 2.3, 2.4)\",2.3,\"( 2.2, 2.4)\",8.3,\"( 7.3, 9.3)\",8.3,\"( 7.4, 9.4)\",\"(33.37676027290, -86.8051937568)\"", "AL,Huntsville,0137000,180105,16.4,\"(16.0, 16.9)\",16.6,\"(16.1, 17.0)\",28.9,\"(28.7, 29.1)\",28.3,\"(28.1, 28.5)\",13.3,\"(13.2, 13.3)\",13.4,\"(13.3, 13.5)\",37.4,\"(37.2, 37.6)\",36.9,\"(36.7, 37.1)\",75.2,\"(75.0, 75.3)\",62.7,\"(62.6, 62.7)\",6.7,\"( 6.7, 6.8)\",6.5,\"( 6.4, 6.5)\",10.9,\"(10.8, 11.0)\",10.8,\"(10.7, 10.9)\",6.7,\"( 6.6, 6.8)\",6.4,\"( 6.3, 6.5)\",71.0,\"(70.9, 71.2)\",70.5,\"(70.4, 70.6)\",80.1,\"(79.9, 80.4)\",80.5,\"(80.2, 80.7)\",71.7,\"(71.3, 72.2)\",71.6,\"(71.1, 72.1)\",8.0,\"( 7.9, 8.2)\",7.8,\"( 7.7, 8.0)\",46.4,\"(45.2, 47.5)\",46.0,\"(44.9, 47.1)\",39.5,\"(38.6, 40.4)\",39.8,\"(38.9, 40.7)\",18.4,\"(18.0, 18.9)\",19.0,\"(18.5, 19.4)\",61.2,\"(60.6, 61.8)\",61.1,\"(60.6, 61.7)\",11.8,\"(11.7, 11.9)\",11.4,\"(11.3, 11.6)\",33.5,\"(33.3, 33.6)\",30.3,\"(30.3, 30.3)\",3.2,\"( 3.2, 3.2)\",3.1,\"( 3.1, 3.2)\",30.6,\"(30.1, 31.0)\",30.7,\"(30.2, 31.1)\",80.2,\"(79.8, 80.7)\",76.5,\"(76.0, 77.0)\",15.1,\"(14.9, 15.3)\",15.1,\"(14.9, 15.3)\",35.5,\"(35.3, 35.8)\",36.2,\"(35.9, 36.4)\",82.9,\"(82.5, 83.2)\",78.2,\"(77.8, 78.6)\",14.5,\"(14.2, 14.7)\",14.4,\"(14.1, 14.6)\",37.8,\"(37.6, 38.1)\",38.3,\"(38.1, 38.6)\",3.6,\"( 3.5, 3.6)\",3.5,\"( 3.4, 3.5)\",14.2,\"(13.4, 15.0)\",14.2,\"(13.4, 15.0)\",\"(34.69896926710, -86.6387042882)\"", "AL,Mobile,0150000,195111,18.1,\"(17.8, 18.5)\",18.5,\"(18.1, 18.9)\",30.2,\"(30.0, 30.4)\",29.0,\"(28.9, 29.2)\",13.6,\"(13.5, 13.7)\",13.9,\"(13.8, 14.0)\",42.2,\"(42.0, 42.3)\",41.2,\"(41.0, 41.3)\",78.7,\"(78.6, 78.8)\",66.2,\"(66.2, 66.2)\",6.5,\"( 6.5, 6.5)\",6.1,\"( 6.1, 6.2)\",11.5,\"(11.4, 11.6)\",11.5,\"(11.4, 11.6)\",7.6,\"( 7.5, 7.7)\",7.1,\"( 7.0, 7.2)\",74.6,\"(74.5, 74.7)\",74.0,\"(73.9, 74.1)\",80.3,\"(80.1, 80.5)\",80.2,\"(80.0, 80.4)\",65.0,\"(64.6, 65.4)\",65.1,\"(64.6, 65.5)\",8.8,\"( 8.7, 9.0)\",8.5,\"( 8.3, 8.6)\",31.8,\"(31.0, 32.6)\",31.6,\"(30.8, 32.4)\",30.7,\"(30.0, 31.4)\",31.5,\"(30.8, 32.1)\",20.5,\"(20.2, 20.8)\",21.2,\"(20.8, 21.5)\",58.7,\"(58.2, 59.1)\",58.4,\"(57.9, 58.9)\",14.2,\"(14.1, 14.3)\",13.5,\"(13.4, 13.6)\",35.2,\"(35.0, 35.3)\",31.5,\"(31.4, 31.5)\",3.7,\"( 3.7, 3.7)\",3.5,\"( 3.5, 3.6)\",35.8,\"(35.4, 36.1)\",35.7,\"(35.4, 36.1)\",82.0,\"(81.7, 82.3)\",77.1,\"(76.7, 77.5)\",16.2,\"(16.1, 16.4)\",16.3,\"(16.2, 16.5)\",37.5,\"(37.4, 37.7)\",38.2,\"(38.0, 38.3)\",85.5,\"(85.2, 85.7)\",80.1,\"(79.8, 80.5)\",15.9,\"(15.7, 16.1)\",15.6,\"(15.4, 15.8)\",39.1,\"(39.0, 39.3)\",39.7,\"(39.5, 39.9)\",4.4,\"( 4.3, 4.4)\",4.2,\"( 4.1, 4.2)\",19.7,\"(18.8, 20.5)\",19.6,\"(18.8, 20.5)\",\"(30.67762486480, -88.1184482714)\"", ...])

#### 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 src/benchmarks/micro/libraries/System.Runtime/Perf.String.cs, especially the Split_Csv benchmark referenced in the report, and run the provided benchmarks_ci.py command to reproduce the measurements. The issue reports performance improvements but does not identify a code change, regression, or acceptance criterion, so the intended definition of done is unresolved.

Written by the indexing model from the issue text.