c# - C#两个几乎相同的线程，性能差异很大

Question

我在C#中拥有一个大型的多线程系统，我意识到两个线程之间的性能差异很大。现在，我设计了两个几乎完全相同的线程，其中一个的执行速度快4-5倍(如果您更改它们必须运行的循环数量，它会线性扩展)。
和不同吗？一种笨拙的条件围绕其中之一的实际重码。这对我来说毫无意义，而且如果这么小的细节可能产生如此巨大的影响，我将无能为力地进行优化。这已在Unity中进行了测试，因此在其他环境中结果可能会有所不同。
线程完成时间:2.8秒。
ThreadB完成时间:0.6秒。
请注意，ThreadB是有条件的(在第一次迭代时，它将立即评估为true)。
如此愚蠢的代码添加如何使实际有效负载(for循环和数字运算)的执行速度如此之快？另外，如果我在ThreadB的情况下直接将“delay”变量更改为静态“0.0”，则其性能再次类似于ThreadA。换句话说:一个单精度 double 型，无论是硬编码值还是引用变量，都会使性能差异提高4-5倍。
不用管实际的算法，这只会使计算机处理一些数字。我知道我要一次又一次地比较相同的数据，这是不重要的。
我不是编译专家，也没有办法探讨实际的计算机/汇编代码中的差异。我只知道两者之间的差异是巨大的，而且对我来说简直是无稽之谈。我想念什么？我偶然发现了这一点，将来我可能无法知道给定线程以20％的可能速度执行，而只需稍作更改便可以解决该问题。
请。我需要一个 Nerd 才能使这一切从纯粹的魔法变成“哦，这就是为什么...!现在我知道将来如何避免它了……”。我知道C#的编译被托管的东西层包围，但是一定有逻辑上的原因。正确的？
这是一些具有一些简单结构的测试代码来支持它。如果有人有时间检查他们是否获得与我相同的结果，我会很高兴。

using System.Threading;

public class ThreadTest
{
    Thread threadA;
    Thread threadB;

    bool runThreadA = false;
    bool runThreadB = false;

    System.Diagnostics.Stopwatch stopWatch;

    double elapsedTimeA = 0;
    double elapsedTimeB = 0;
    
    public ThreadTest()
    {
        stopWatch = new System.Diagnostics.Stopwatch();
        StartThreads();
    }

    public void StartThreads ()
    {
        stopWatch.Reset();
        stopWatch.Start();
        threadA = new Thread(ThreadA);
        threadB = new Thread(ThreadB);

        runThreadA = true;
        runThreadB = true;

        elapsedTimeA = 0;
        elapsedTimeB = 0;
        threadA.Start();
        threadB.Start();
    }

    void ThreadA ()
    {
        while (runThreadA)
        {
            
            runThreadA = false;
            double preTicks = stopWatch.ElapsedTicks;

            Line3Double lineA = new Line3Double(new Vector3DoublePrecision(10, 20, 30), new Vector3DoublePrecision(100, 140, 180));
            Line3Double lineB = new Line3Double(new Vector3DoublePrecision(-10, -20, -30), new Vector3DoublePrecision(-100, -140, -180));

            int lines = 1000;

            for (int i = 0; i < 8; i++)
            {
                for (int j = 0; j < lines; j++)
                {
                    double aStartX = lineA.startX;
                    double aStartY = lineA.startY;
                    double aStartZ = lineA.startZ;

                    double aEndX = lineA.endX;
                    double aEndY = lineA.endY;
                    double aEndZ = lineA.endZ;

                    double aDirX = lineA.dirX;
                    double aDirY = lineA.dirY;
                    double aDirZ = lineA.dirZ;

                    double aDotSelf = lineA.dotSelf;

                    for (int k = 0; k < 8; k++)
                    {
                        for (int l = 0; l < lines; l++)
                        {
                            double wX = aStartX - lineB.startX;
                            double wY = aStartY - lineB.startY;
                            double wZ = aStartZ - lineB.startZ;

                            double b = aDirX * lineB.dirX + aDirY * lineB.dirY + aDirZ * lineB.dirZ;
                            double d = aDirX * wX + aDirY * wY + aDirZ * wZ;
                            double e = lineB.dirX * wX + lineB.dirY * wY + lineB.dirZ * wZ;

                            double D = aDotSelf * lineB.dotSelf - b * b;
                            double sc, tc;
                            if (D < 0.0000001)
                            {
                                sc = 0.0f;
                                tc = (b > lineB.dotSelf ? d / b : e / lineB.dotSelf);
                            }
                            else
                            {
                                sc = (b * e - lineB.dotSelf * d) / D;
                                tc = (aDotSelf * e - b * d) / D;
                            }

                            double shortestX = wX + (sc * aDirX) - (tc * lineB.dirX);
                            double shortestY = wY + (sc * aDirY) - (tc * lineB.dirY);
                            double shortestZ = wZ + (sc * aDirZ) - (tc * lineB.dirZ);

                            double distance = shortestX * shortestX + shortestY * shortestY + shortestZ * shortestZ;
                        }
                    }
                }
            }

            double postTicks = stopWatch.ElapsedTicks;
            double time = ((postTicks - preTicks) / System.Diagnostics.Stopwatch.Frequency) * 1000;
            elapsedTimeA = time;
        }
    }

    void ThreadB()
    {
        long startTicks = stopWatch.ElapsedTicks;
        double delay = 0;

        while (runThreadB)
        {
            if ((double)(stopWatch.ElapsedTicks - startTicks) / System.Diagnostics.Stopwatch.Frequency >= delay)
            {
                runThreadB = false;
                double preTicks = stopWatch.ElapsedTicks;

                Line3Double lineA = new Line3Double(new Vector3DoublePrecision(10, 20, 30), new Vector3DoublePrecision(100, 140, 180));
                Line3Double lineB = new Line3Double(new Vector3DoublePrecision(-10, -20, -30), new Vector3DoublePrecision(-100, -140, -180));

                int lines = 1000;

                for (int i = 0; i < 8; i++)
                {
                    for (int j = 0; j < lines; j++)
                    {
                        double aStartX = lineA.startX;
                        double aStartY = lineA.startY;
                        double aStartZ = lineA.startZ;

                        double aEndX = lineA.endX;
                        double aEndY = lineA.endY;
                        double aEndZ = lineA.endZ;

                        double aDirX = lineA.dirX;
                        double aDirY = lineA.dirY;
                        double aDirZ = lineA.dirZ;

                        double aDotSelf = lineA.dotSelf;

                        for (int k = 0; k < 8; k++)
                        {
                            for (int l = 0; l < lines; l++)
                            {
                                double wX = aStartX - lineB.startX;
                                double wY = aStartY - lineB.startY;
                                double wZ = aStartZ - lineB.startZ;

                                double b = aDirX * lineB.dirX + aDirY * lineB.dirY + aDirZ * lineB.dirZ;
                                double d = aDirX * wX + aDirY * wY + aDirZ * wZ;
                                double e = lineB.dirX * wX + lineB.dirY * wY + lineB.dirZ * wZ;

                                double D = aDotSelf * lineB.dotSelf - b * b;
                                double sc, tc;
                                if (D < 0.0000001)
                                {
                                    sc = 0.0f;
                                    tc = (b > lineB.dotSelf ? d / b : e / lineB.dotSelf);
                                }
                                else
                                {
                                    sc = (b * e - lineB.dotSelf * d) / D;
                                    tc = (aDotSelf * e - b * d) / D;
                                }

                                double shortestX = wX + (sc * aDirX) - (tc * lineB.dirX);
                                double shortestY = wY + (sc * aDirY) - (tc * lineB.dirY);
                                double shortestZ = wZ + (sc * aDirZ) - (tc * lineB.dirZ);

                                double distance = shortestX * shortestX + shortestY * shortestY + shortestZ * shortestZ;
                            }
                        }
                    }
                }

                double postTicks = stopWatch.ElapsedTicks;
                double time = ((postTicks - preTicks) / System.Diagnostics.Stopwatch.Frequency) * 1000;
                elapsedTimeB = time;
            }
        }
    }
}
public struct Vector3DoublePrecision
{
    public double x;
    public double y;
    public double z;

    public Vector3DoublePrecision(double x, double y, double z)
    {
        this.x = x;
        this.y = y;
        this.z = z;
    }
}

public struct Line3Double
{
    public double startX;
    public double startY;
    public double startZ;
    public double endX;
    public double endY;
    public double endZ;

    public double dirX;
    public double dirY;
    public double dirZ;

    public double dotSelf;

    public Line3Double(Vector3DoublePrecision start, Vector3DoublePrecision end)
    {
        startX = start.x;
        startY = start.y;
        startZ = start.z;

        endX = end.x;
        endY = end.y;
        endZ = end.z;

        dirX = end.x - start.x;
        dirY = end.y - start.y;
        dirZ = end.z - start.z;

        dotSelf = dirX * dirX + dirY * dirY + dirZ * dirZ;
    }
}

Answer 1

解决了...是Unity特定的编译问题。将脚本后端从Mono更改为IL2CPP，不仅使所有功能都表现得更好，而且还消除了上述问题。因此，应归咎于JIT编译。仍然不确定如此笨拙的条件如何使我的线程比没有线程更好地执行，但是现在它可以工作了。通过修复，我学到了很多东西。