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Regressions in System.Buffers.Text.Tests.Base64EncodeDecodeInPlaceTests #86336
Description
Run Information
| Name | Value |
|---|---|
| Architecture | x64 |
| OS | ubuntu 18.04 |
| Queue | TigerUbuntu |
| Baseline | 05a3d360d6079db3cb64636fcdf99f832a58c1d2 |
| Compare | bc1175382857c4af11c27b3134fd22dc8377dfb5 |
| Diff | Diff |
| Configs | CompilationMode:tiered, RunKind:micro |
Regressions in System.Buffers.Text.Tests.Base64EncodeDecodeInPlaceTests
| Benchmark | Baseline | Test | Test/Base | Test Quality | Edge Detector | Baseline IR | Compare IR | IR Ratio | Baseline ETL | Compare ETL |
|---|---|---|---|---|---|---|---|---|---|---|
| Base64DecodeInPlace - Duration of single invocation | 113.82 ms | 143.74 ms | 1.26 | 0.01 | True |
Repro
General Docs link: https://github.com/dotnet/performance/blob/main/docs/benchmarking-workflow-dotnet-runtime.md
Payloads
git clone https://github.com/dotnet/performance.git
python3 .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Buffers.Text.Tests.Base64EncodeDecodeInPlaceTests*'Details
Payloads
Histogram
System.Buffers.Text.Tests.Base64EncodeDecodeInPlaceTests.Base64DecodeInPlace(NumberOfBytes: 200000000)
Description of detection logic
IsRegressionBase: Marked as regression because the compare was 5% greater than the baseline, and the value was not too small.
IsRegressionChecked: Marked as regression because the three check build points were 0.05 greater than the baseline.
IsImprovementBase: Marked as not an improvement because the compare was not 5% less than the baseline, or the value was too small.
IsRegressionBase: Marked as regression because the compare was 5% greater than the baseline, and the value was not too small.
IsRegressionChecked: Marked as regression because the three check build points were 0.05 greater than the baseline.
IsRegressionWindowed: Marked as regression because 143.736245 > 119.5565114153846.
IsChangePoint: Marked as a change because one of 2/24/2023 8:06:06 PM, 5/8/2023 3:52:55 PM, 5/16/2023 7:34:13 AM falls between 5/7/2023 5:11:33 AM and 5/16/2023 7:34:13 AM.
IsRegressionStdDev: Marked as regression because -207.8542267672069 (T) = (0 -144284018.73783883) / Math.Sqrt((31267341672.962914 / (15)) + (484350566709.22046 / (25))) is less than -2.0243941639098457 = MathNet.Numerics.Distributions.StudentT.InvCDF(0, 1, (15) + (25) - 2, .025) and -0.26747237620001 = (113836026.28912087 - 144284018.73783883) / 113836026.28912087 is less than -0.05.
IsImprovementBase: Marked as not an improvement because the compare was not 5% less than the baseline, or the value was too small.
IsChangeEdgeDetector: Marked as regression because Edge Detector said so.
JIT Disasms
Docs
Profiling workflow for dotnet/runtime repository
Benchmarking workflow for dotnet/runtime repository
Activity
[-][Perf] Linux/x64: 1 Regression on 5/9/2023 7:00:05 PM[/-][+]Regressions in System.Buffers.Text.Tests.Base64EncodeDecodeInPlaceTests[/+]EgorBo commentedon May 16, 2023
Regressed in #85938 cc @stephentoub
stephentoub commentedon May 16, 2023
I'll take a look. We weren't expecting such regressions for existing input.
gfoidl commentedon May 16, 2023
May this come from
runtime/src/libraries/System.Private.CoreLib/src/System/Buffers/Text/Base64Decoder.cs
Line 460 in 80ffe5c
outparam, and not a local anymore? (So stack vs. register)