[Perf] Linux/x64: 4 Regressions on 2/25/2024 4:37:10 PM

[performanceautofiler]

Run Information

Name	Value
Architecture	x64
OS	ubuntu 22.04
Queue	TigerUbuntu
Baseline	f32c428c86b4cc41e88e2e5a750c37dfb354e33a
Compare	5ef47c852ffd51aaeb52e34391fe4fed261c9f26
Diff	Diff
Configs	CompilationMode:tiered, RunKind:micro

Regressions in System.Text.Tests.Perf_StringBuilder

Benchmark	Baseline	Test	Test/Base	Test Quality	Edge Detector	Baseline IR	Compare IR	IR Ratio
ToString_MultipleSegments - Duration of single invocation 📝 - Benchmark Source 📈 - ADX Test Multi Config Graph	87.46 μs	101.66 μs	1.16	0.00	False

Test Report

Repro

General Docs link: https://github.com/dotnet/performance/blob/main/docs/benchmarking-workflow-dotnet-runtime.md

git clone https://github.com/dotnet/performance.git
python3 .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Text.Tests.Perf_StringBuilder*'

Payloads

Baseline
Compare

System.Text.Tests.Perf_StringBuilder.ToString_MultipleSegments(length: 100000)

ETL Files

Histogram

JIT Disasms

Docs

Profiling workflow for dotnet/runtime repository
Benchmarking workflow for dotnet/runtime repository

[DrewScoggins]

From #98623

Improvements:
dotnet/perf-autofiling-issues#29825
dotnet/perf-autofiling-issues#29808

[mangod9]

@EgorBo is this by design, so it could be closed?

[EgorBo]

@EgorBot -amd64 -intel -perf -commit 79dd9ba vs fab69ef --disasm

using BenchmarkDotNet.Attributes;
using System.Text;

public class MyProgram
{
    const int LOHAllocatedStringSize = 100_000;
    private string _stringLOH;
    private string _string100;
    private StringBuilder _builderSingleSegment100;
    private StringBuilder _builderSingleSegmentLOH;
    private StringBuilder _builderMultipleSegments100;
    private StringBuilder _builderMultipleSegmentsLOH;

    [GlobalSetup(Target = nameof(ToString_MultipleSegments))]
    public void Setup_ToString_MultipleSegments()
    {
        _builderMultipleSegments100 = Append_Char(100); // 16 + 32 + 48 + 96 char segments
        _builderMultipleSegmentsLOH = Append_Char(LOHAllocatedStringSize);
    }

    public StringBuilder Append_Char(int length)
    {
        StringBuilder builder = new StringBuilder();
        for (int i = 0; i < length; i++)
            builder.Append('a');
        return builder;
    }

    [Benchmark]
    [Arguments(LOHAllocatedStringSize)]
    public string ToString_MultipleSegments(int length) => (length == 100 ? _builderMultipleSegments100 : _builderMultipleSegmentsLOH).ToString();
}