ReadOnlySpan 最適化

SpanBenchmark.cs

using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Running;

BenchmarkRunner.Run<SpanBenchmark>();

[MemoryDiagnoser]
public class SpanBenchmark
{
    private const int N = 1000;

    [Benchmark]
    public void IntArray()
    {
        for (int i = 0; i < N; i++)
        {
            m(i);
        }

        static int m(int i)
        {
            ReadOnlySpan<int> table = new[] { 1, 0, -1, 0 }; // 差はこの行だけ
            return table[i % 4];
        }
    }

    [Benchmark]
    public void SByteArray()
    {
        for (int i = 0; i < N; i++)
        {
            m(i);
        }

        static int m(int i)
        {
            ReadOnlySpan<sbyte> table = new sbyte[] { 1, 0, -1, 0 }; // 差はこの行だけ
            return table[i % 4];
        }
    }
}