C#直接賦值和反射賦值（無GC）的性能比較

using System;
using System.Reflection;
using System.Diagnostics;
using System.Runtime.InteropServices;

namespace Field
{
    struct Test
    {
        public float X;
    }

    class MainClass
    {
        const int loops = 10000000;

        Stopwatch m_StopWatch = new Stopwatch();
        Test m_Test;
        object m_Target;
        object m_Value;
        FieldInfo m_Field;
        public MainClass()
        {
            m_Target = m_Test;
            Type t = typeof(Test);
            m_Field = t.GetField("X");
            m_Value = m_Field.GetValue(m_Test);
        }

        public void Test1()
        {
            m_StopWatch.Reset();
            m_StopWatch.Start();
            for (int i = 0; i < loops; ++i)
            {
                m_Test.X = (float)i;
            }
            m_StopWatch.Stop();

            Console.WriteLine("Test1: " + m_StopWatch.ElapsedMilliseconds + " ms");
        }

        public unsafe void Test2()
        {
            m_StopWatch.Reset();
            m_StopWatch.Start();
            for (int i = 0; i < loops; ++i)
            {
                GCHandle gcHandle = GCHandle.Alloc(m_Value, GCHandleType.Pinned);
                IntPtr rawPtr = gcHandle.AddrOfPinnedObject();
                float* buffer = (float*)rawPtr.ToPointer();
                *buffer = (float)i;
                gcHandle.Free();
                m_Field.SetValueDirect(__makeref(m_Test), m_Value);
            }
            m_StopWatch.Stop();

            Console.WriteLine("Test2: " + m_StopWatch.ElapsedMilliseconds + " ms");
        }

        public unsafe void Test3()
        {
            m_StopWatch.Reset();
            m_StopWatch.Start();
            for (int i = 0; i < loops; ++i)
            {
                GCHandle gcHandle = GCHandle.Alloc(m_Value, GCHandleType.Pinned);
                IntPtr rawPtr = gcHandle.AddrOfPinnedObject();
                float* buffer = (float*)rawPtr.ToPointer();
                *buffer = (float)i;
                gcHandle.Free();
                m_Field.SetValue(m_Target, m_Value);
                m_Test = (Test)m_Target;
            }
            m_StopWatch.Stop();

            Console.WriteLine("Test3: " + m_StopWatch.ElapsedMilliseconds + " ms");
        }

        public static void Main(string[] args)
        {
            MainClass main = new MainClass();
            main.Test1();
            main.Test2();
            main.Test3();

            Console.ReadKey();
        }
    }
}

Xamarin - Release

Test1: 35 ms

Test2: 3237 ms

Test3: 5189 ms