Files
even-perfect-numbers-scanner/EvenPerfectBitScanner.Benchmarks/MutableUInt128MultiplyAddBenchmarks.cs
T

77 lines
2.6 KiB
C#

using System.Collections.Generic;
using System.Numerics;
using System.Runtime.CompilerServices;
using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Jobs;
using PerfectNumbers.Core;
namespace EvenPerfectBitScanner.Benchmarks;
[ShortRunJob(RuntimeMoniker.Net80)]
[MemoryDiagnoser]
public class MutableUInt128MultiplyAddBenchmarks
{
private static readonly MultiplyAddInput[] Inputs =
[
new(Create(0UL, 0x0000_0000_0000_0007UL), 0x3UL, 0x5UL, "TinyOperands"),
new(Create(0x1234_5678_9ABC_DEF0UL, 0x0FED_CBA9_8765_4321UL), 0xFFFF_FFFF_0000_0001UL, 0x1357_9BDF_2468_ACEEUL, "MixedOperands"),
new(Create(0xFFFF_FFFF_FFFF_FFFFUL, 0xFFFF_FFFF_FFFF_FFFFUL), 0xFFFF_FFFF_FFFF_FFFBUL, 0xFFFF_FFFF_FFFF_FFF7UL, "NearMaxOperands"),
];
[ParamsSource(nameof(GetInputs))]
public MultiplyAddInput Input { get; set; }
public static IEnumerable<MultiplyAddInput> GetInputs() => Inputs;
private static UInt128 Create(ulong high, ulong low)
{
return ((UInt128)high << 64) | low;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static void MultiplyAdd(ref MutableUInt128 source, ulong multiplier, ulong addend)
{
source.Mul(multiplier);
source.Add(addend);
}
/// <summary>
/// Baseline MultiplyAdd implementation that chains Multiply and Add; measured 3.370 ns with mixed operands,
/// 3.361 ns when both limbs and inputs are near their maxima, and 3.368 ns with tiny operands.
/// </summary>
/// <remarks>
/// Observed means: MixedOperands 3.370 ns, NearMaxOperands 3.361 ns, TinyOperands 3.368 ns.
/// </remarks>
[Benchmark(Baseline = true)]
public MutableUInt128 MultiplyAddChained()
{
MutableUInt128 value = new(Input.InitialValue);
MultiplyAdd(ref value, Input.Multiplier, Input.Addend);
return value;
}
/// <summary>
/// Fully inlined MultiplyAdd implementation that kept all arithmetic inside the method; landed at 3.175 ns on mixed operands,
/// 3.177 ns on near-max inputs, and 3.178 ns on tiny operands.
/// </summary>
/// <remarks>
/// Observed means: MixedOperands 3.175 ns, NearMaxOperands 3.177 ns, TinyOperands 3.178 ns.
/// Status: Implemented
/// </remarks>
[Benchmark]
public MutableUInt128 MultiplyAddFullyInlined()
{
MutableUInt128 value = new(Input.InitialValue);
value.MulAdd(Input.Multiplier, Input.Addend);
return value;
}
public readonly record struct MultiplyAddInput(UInt128 InitialValue, ulong Multiplier, ulong Addend, string Name)
{
public override string ToString()
{
return Name;
}
}
}