无锁

多个关联数据无法完整获取修改

 internal class Program
 {
     static void Main(string[] args)
     {
         Console.WriteLine("Hello, World!");
         ThreadPool.QueueUserWorkItem(Thread1);
         ThreadPool.QueueUserWorkItem(Thread2);
         ThreadPool.QueueUserWorkItem(Thread3);

         Console.ReadKey();
     }

     public static int[] Datas = new int[3];

     public static void Thread1(object o)
     {
         Datas[0] = 100;
         Thread.Sleep(5000);
         Datas[1] = 101;
         Thread.Sleep(2000);
         Datas[2] = 120;
     }

     public static void Thread2(object o)
     {
         while (true)
         {
             Console.WriteLine($"Thread2:0->{Datas[0]},1->{Datas[1]},2->{Datas[2]}");

             Thread.Sleep(1000);
         }
     }

     private static void Thread3(object? state)
     {
         while (true)
         {
             Console.WriteLine($"Thread3:0->{Datas[0]},1->{Datas[1]},2->{Datas[2]}");

             Thread.Sleep(1000);
         }
     }
 }

锁

加上lock锁

每次需要等其他线程解锁了才能用

自旋锁

遇到上锁时，短暂循环等待，线程不挂起

internal class Program
{
    static int _lock = 0;

    static void Main(string[] args)
    {
        Console.WriteLine("Hello, World!");
        Console.WriteLine($"time:{DateTime.Now.ToString("HH:mm:ss.fff")}");
        ThreadPool.QueueUserWorkItem(Thread1);
        ThreadPool.QueueUserWorkItem(Thread2);
        ThreadPool.QueueUserWorkItem(Thread3);

        Console.ReadKey();
    }

    public static int[] Datas = new int[3];

    public static void Thread1(object o)
    {
        while (Interlocked.Exchange(ref _lock, 1) != 0)
        {
            Thread.SpinWait(1);
        }

        Datas[0] = 100;
        Thread.Sleep(5000);
        Datas[1] = 101;
        Thread.Sleep(2000);
        Datas[2] = 120;
        Console.WriteLine($"write finish,time:{DateTime.Now.ToString("HH:mm:ss.fff")}");
        //lock (Datas)
        //{

        //}
        Interlocked.Exchange(ref _lock, 0);
    }

    public static void Thread2(object o)
    {
        while (true)
        {
            while (Interlocked.Exchange(ref _lock, 1) != 0)
            {
                Thread.SpinWait(1);
            }
            //lock (Datas)
            //{
            Console.WriteLine(
                $"Thread2:0->{Datas[0]},1->{Datas[1]},2->{Datas[2]},time:{DateTime.Now.ToString("HH:mm:ss.fff")}"
            );
            Thread.Sleep(1000);
            //}
            Interlocked.Exchange(ref _lock, 0);
        }
    }

    private static void Thread3(object? state)
    {
        while (true)
        {
            while (Interlocked.Exchange(ref _lock, 1) != 0)
            {
                Thread.SpinWait(1);
            }
            Console.WriteLine(
                $"Thread3:0->{Datas[0]},1->{Datas[1]},2->{Datas[2]},time:{DateTime.Now.ToString("HH:mm:ss.fff")}"
            );

            Thread.Sleep(1000);
            Interlocked.Exchange(ref _lock, 0);
        }
    }
}

读写锁

写入时，唯一线程写入，读的时候可以多个线程同时读取

    internal class Program
    {
        static ReaderWriterLockSlim _lock = new ReaderWriterLockSlim();

        static void Main(string[] args)
        {
            Console.WriteLine("Hello, World!");
            Console.WriteLine($"time:{DateTime.Now.ToString("HH:mm:ss.fff")}");
            ThreadPool.QueueUserWorkItem(Thread1);
            ThreadPool.QueueUserWorkItem(Thread2);
            ThreadPool.QueueUserWorkItem(Thread3);

            Console.ReadKey();
        }

        public static int[] Datas = new int[3];

        public static void Thread1(object o)
        {
            _lock.EnterWriteLock();

            try
            {
                Datas[0] = 100;
                Thread.Sleep(5000);
                Datas[1] = 101;
                Thread.Sleep(2000);
                Datas[2] = 120;
                Console.WriteLine($"write finish,time:{DateTime.Now.ToString("HH:mm:ss.fff")}");
            }
            catch (Exception) { }
            finally
            {
                _lock.ExitWriteLock();
            }
        }

        public static void Thread2(object o)
        {
            while (true)
            {
                _lock.EnterReadLock();
                try
                {
                    Console.WriteLine(
                        $"Thread2:0->{Datas[0]},1->{Datas[1]},2->{Datas[2]},time:{DateTime.Now.ToString("HH:mm:ss.fff")}"
                    );
                    Thread.Sleep(1000);
                }
                catch (Exception) { }
                finally
                {
                    _lock.ExitReadLock();
                }
            }
        }

        private static void Thread3(object? state)
        {
            while (true)
            {
                _lock.EnterReadLock();
                try
                {
                    Console.WriteLine(
                        $"Thread3:0->{Datas[0]},1->{Datas[1]},2->{Datas[2]},time:{DateTime.Now.ToString("HH:mm:ss.fff")}"
                    );

                    Thread.Sleep(1000);
                }
                catch (Exception) { }
                finally
                {
                    _lock.ExitReadLock();
                }
            }
        }
    }