42 lines
1.4 KiB
C#
42 lines
1.4 KiB
C#
using System.Runtime.CompilerServices;
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using BenchmarkDotNet.Attributes;
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using BenchmarkDotNet.Jobs;
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namespace EvenPerfectBitScanner.Benchmarks;
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[MemoryDiagnoser]
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[SimpleJob(RuntimeMoniker.Net80, launchCount: 1, warmupCount: 1, iterationCount: 5)]
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public class Mod8ULongBenchmarks
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{
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[Params(8UL, 8191UL, 131071UL, 2147483647UL, ulong.MaxValue - 127UL)]
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public ulong Value { get; set; }
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/// <summary>
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/// Uses the built-in <c>% 8</c>; measured 0.0224 ns on Value=8, ~0 ns within the measurement noise floor for 8,191,
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/// 0.0069 ns for 131,071, 0.0117 ns for 2,147,483,647, and 0.107 ns for the near-maximum value, making it the fastest
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/// option except when the branch-free mask wins on huge operands.
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/// </summary>
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[Benchmark(Baseline = true)]
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public ulong ModuloOperator()
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{
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return Value % 8UL;
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}
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/// <summary>
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/// Applies the branch-free mask helper; costs 0.0344 ns on Value=8, 0.0296 ns on 8,191, 0.0114 ns on 131,071,
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/// 0.0106 ns on 2,147,483,647, and just 0.0109 ns on the near-maximum sample, overtaking <c>%</c> once the divisor
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/// approaches 2<sup>64</sup>.
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/// </summary>
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[Benchmark]
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public ulong ExtensionMethod()
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{
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return Mod8(Value);
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}
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[MethodImpl(MethodImplOptions.AggressiveInlining)]
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private static ulong Mod8(ulong value)
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{
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return value & 7UL;
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}
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}
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