95 lines
3.3 KiB
C#
95 lines
3.3 KiB
C#
using System.Runtime.CompilerServices;
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using BenchmarkDotNet.Attributes;
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using BenchmarkDotNet.Jobs;
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using PerfectNumbers.Core;
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namespace EvenPerfectBitScanner.Benchmarks;
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[SimpleJob(RuntimeMoniker.Net80, launchCount: 1, warmupCount: 1, iterationCount: 5)]
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[MemoryDiagnoser]
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public class Mod7Benchmarks
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{
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private static readonly ModBenchmarkCase[] Cases =
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[
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new(ModNumericType.UInt32, 7U, "UInt32:7"),
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new(ModNumericType.UInt32, 2047U, "UInt32:2047"),
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new(ModNumericType.UInt32, 65535U, "UInt32:65535"),
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new(ModNumericType.UInt32, 2147483647U, "UInt32:2147483647"),
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new(ModNumericType.UInt64, 7UL, "UInt64:7"),
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new(ModNumericType.UInt64, 8191UL, "UInt64:8191"),
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new(ModNumericType.UInt64, 131071UL, "UInt64:131071"),
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new(ModNumericType.UInt64, 2147483647UL, "UInt64:2147483647"),
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new(ModNumericType.UInt64, ulong.MaxValue - 63UL, "UInt64:Max-63"),
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new(ModNumericType.UInt128, 7UL, "UInt128:7"),
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new(ModNumericType.UInt128, 8191UL, "UInt128:8191"),
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new(ModNumericType.UInt128, 131071UL, "UInt128:131071"),
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new(ModNumericType.UInt128, 2147483647UL, "UInt128:2147483647"),
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new(ModNumericType.UInt128, ulong.MaxValue - 127UL, "UInt128:Max-127"),
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];
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public static IEnumerable<ModBenchmarkCase> GetCases() => Cases;
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[MethodImpl(MethodImplOptions.AggressiveInlining)]
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private static uint Mod7(uint value)
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{
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uint remainder = 0U;
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while (value != 0U)
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{
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remainder += value & 7U;
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value >>= 3;
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if (remainder >= 7U)
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{
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remainder -= 7U;
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}
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}
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return remainder >= 7U ? remainder - 7U : remainder;
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}
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[MethodImpl(MethodImplOptions.AggressiveInlining)]
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private static ulong Mod7(ulong value)
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{
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ulong remainder = ((uint)value % 7U) + (((uint)(value >> 32) % 7U) << 2);
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while (remainder >= 7UL)
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{
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remainder -= 7UL;
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}
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return remainder;
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}
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/// <summary>
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/// `% 7` baseline across the merged dataset; hovered near the noise floor on <c>uint</c>, 0.27 ns on <c>ulong</c>, and
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/// 2.86-2.91 ns on <see cref="UInt128"/> inputs.
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/// </summary>
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[Benchmark(Baseline = true)]
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[ArgumentsSource(nameof(GetCases))]
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public ulong ModuloOperator(ModBenchmarkCase data)
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{
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return data.Type switch
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{
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ModNumericType.UInt32 => (uint)data.Value % 7U,
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ModNumericType.UInt64 => (ulong)data.Value % 7UL,
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ModNumericType.UInt128 => (ulong)(data.Value % 7UL),
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_ => throw new ArgumentOutOfRangeException(nameof(data)),
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};
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}
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/// <summary>
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/// Extension helpers; dramatically slower on <c>uint</c>, modestly slower on <c>ulong</c>, and 3.2-4.2× faster on
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/// <see cref="UInt128"/> inputs where the folding helpers shine.
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/// </summary>
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[Benchmark]
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[ArgumentsSource(nameof(GetCases))]
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public ulong ExtensionMethod(ModBenchmarkCase data)
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{
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return data.Type switch
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{
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ModNumericType.UInt32 => Mod7((uint)data.Value),
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ModNumericType.UInt64 => Mod7((ulong)data.Value),
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ModNumericType.UInt128 => data.Value.Mod7(),
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_ => throw new ArgumentOutOfRangeException(nameof(data)),
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};
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}
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}
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