From 9a3c56aaabfb0c6bc26433a20362ef24698d9502 Mon Sep 17 00:00:00 2001 From: bicijinlian Date: Sun, 9 Apr 2023 13:34:06 +0800 Subject: [PATCH] =?UTF-8?q?docs:=20=E6=9B=B4=E6=96=B0=E6=96=87=E6=A1=A3?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- Docs/Jupyter笔记.2.5.原子操作.ipynb | 426 +++++++++++++++++++++- MultiThreadingStudy.ConsoleApp/Program.cs | 3 +- 2 files changed, 427 insertions(+), 2 deletions(-) diff --git a/Docs/Jupyter笔记.2.5.原子操作.ipynb b/Docs/Jupyter笔记.2.5.原子操作.ipynb index 160fe8c..de080da 100644 --- a/Docs/Jupyter笔记.2.5.原子操作.ipynb +++ b/Docs/Jupyter笔记.2.5.原子操作.ipynb @@ -120,7 +120,7 @@ "cell_type": "markdown", "metadata": {}, "source": [ - "### Increment\n", + "### 原子递增 Interlocked.Increment()\n", "Interlocked.Increment 函数执行的原子操作属于 “获取-添加”分类，执行后变量的值增加1，返回的值是增加后的值，即增加前的值加1" ] }, @@ -178,6 +178,430 @@ "\n", "//原子操作，多线程下多次执行结果相同" ] + }, + { + "attachments": {}, + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## 原子递减 Interlocked.Decrement()" + ] + }, + { + "attachments": {}, + "cell_type": "markdown", + "metadata": {}, + "source": [ + "属于 `获取-添加`分类，执行后变量的值减少1，返回值是减少后的值即原值减1" + ] + }, + { + "cell_type": "code", + "execution_count": null, + "metadata": { + "dotnet_interactive": { + "language": "csharp" + }, + "polyglot_notebook": { + "kernelName": "csharp" + }, + "vscode": { + "languageId": "polyglot-notebook" + } + }, + "outputs": [], + "source": [ + "#region 原子递减\n", + "//原子递减\n", + "public class Counter4Decrement\n", + "{\n", + " //总次数\n", + " public static int TotalNumber = 0;\n", + " \n", + " //方法循环次数\n", + " public static readonly int LoopNumber = 10000;\n", + "\n", + " //执行\n", + " public static void Decrement()\n", + " {\n", + " for (int i = 1; i <= LoopNumber; i++)\n", + " {\n", + " //原子操作：循环递减,返回递减后的值\n", + " var decreValue = System.Threading.Interlocked.Decrement(ref TotalNumber);\n", + " }\n", + " Console.WriteLine($\"线程[{Thread.CurrentThread.Name}] 执行了递减 {LoopNumber} 次，结束时 TotalNumber = {TotalNumber}\");\n", + " }\n", + "}\n", + "\n", + "//使用域隔离和代码折叠\n", + "{\n", + " var threads = new List()\n", + " {\n", + " new Thread(Counter4Decrement.Decrement){Name=\"thread_a\"},\n", + " new Thread(Counter4Decrement.Decrement){Name=\"thread_b\"}\n", + " };\n", + "\n", + " threads.ForEach(t => t.Start());\n", + " threads.ForEach(t => t.Join());\n", + "\n", + " //主线程信息\n", + " Console.WriteLine($\"主(执行)线程[{Thread.CurrentThread.Name}] 结束时，TotalLoopNumber = {Counter4Decrement.TotalNumber}\");\n", + "}\n", + "\n", + "//原子操作：\n", + "//1、多线程下,每线程执行结束后共享变量可能不同\n", + "//2、所有线程结束, 主线程获取的变量值与最后完成的线程值相同\n", + "#endregion" + ] + }, + { + "attachments": {}, + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## 原子增加指定数量(负数为减) Interlocked.Add()" + ] + }, + { + "attachments": {}, + "cell_type": "markdown", + "metadata": {}, + "source": [ + "Interlocked.Add 属于 `获取-添加`分类，执行后变量的值加等于第二个参数的值，返回值是增加后的值即原值加第二个参数值" + ] + }, + { + "cell_type": "code", + "execution_count": null, + "metadata": { + "dotnet_interactive": { + "language": "csharp" + }, + "polyglot_notebook": { + "kernelName": "csharp" + }, + "vscode": { + "languageId": "polyglot-notebook" + } + }, + "outputs": [], + "source": [ + "//原子增加指定数量\n", + "public class Counter4Add\n", + "{\n", + " //共享变量\n", + " public static int ShareNumber = 0;\n", + "\n", + " //执行\n", + " public static void Add()\n", + " {\n", + " //随机休眠，打乱多线程执行顺序\n", + " Thread.Sleep(Random.Shared.Next(100,500));\n", + "\n", + " //原子操作：增加指定数量\n", + " var decreValue = System.Threading.Interlocked.Add(ref ShareNumber,2);\n", + " Console.WriteLine($\"线程[{Thread.CurrentThread.Name}] 递减2后， ShareNumber = {ShareNumber}\");\n", + " }\n", + "}\n", + "\n", + "//使用域隔离和代码折叠\n", + "{\n", + " var threads = new List()\n", + " {\n", + " new Thread(Counter4Add.Add){Name=\"thread_a\"},\n", + " new Thread(Counter4Add.Add){Name=\"thread_b\"}\n", + " };\n", + "\n", + " threads.ForEach(t => t.Start());\n", + " threads.ForEach(t => t.Join());\n", + "\n", + " //主线程信息\n", + " Console.WriteLine($\"主[执行]线程获共享变量 ShareNumber 最终的值 = {Counter4Add.ShareNumber}\");\n", + "}\n", + "\n", + "//原子操作：\n", + "//1、两个线程同时执行会输出: 2 4 或 4 2\n", + "//2、全局变量最终的值为 4" + ] + }, + { + "attachments": {}, + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## 原子替换 Interlocked.Exchange()" + ] + }, + { + "attachments": {}, + "cell_type": "markdown", + "metadata": {}, + "source": [ + "Interlocked.Exchange() 属于 `测试-设置` 分类, 将变量的值修改为第二个参数的值，返回修改前的值" + ] + }, + { + "cell_type": "code", + "execution_count": null, + "metadata": { + "dotnet_interactive": { + "language": "csharp" + }, + "polyglot_notebook": { + "kernelName": "csharp" + }, + "vscode": { + "languageId": "polyglot-notebook" + } + }, + "outputs": [], + "source": [ + "//原子替换\n", + "public class Counter4Exchange\n", + "{\n", + " //共享变量\n", + " public static int ShareNumber = 0;\n", + "\n", + " //执行\n", + " public static void Exchange()\n", + " {\n", + " //随机休眠，打乱多线程执行顺序\n", + " Thread.Sleep(Random.Shared.Next(100,500));\n", + "\n", + " //原子操作：替换\n", + " var oldValue = System.Threading.Interlocked.Exchange(ref ShareNumber,1);\n", + " Console.WriteLine($\"线程[{Thread.CurrentThread.Name}] 替换前的值为 {oldValue}\");\n", + " }\n", + "}\n", + "\n", + "//使用域隔离和代码折叠\n", + "{\n", + " var threads = new List()\n", + " {\n", + " new Thread(Counter4Exchange.Exchange){Name=\"thread_a\"},\n", + " new Thread(Counter4Exchange.Exchange){Name=\"thread_b\"}\n", + " };\n", + "\n", + " threads.ForEach(t => t.Start());\n", + " threads.ForEach(t => t.Join());\n", + "\n", + " //主线程信息\n", + " Console.WriteLine($\"主[执行]线程获共享变量 ShareNumber 最终的值 = {Counter4Exchange.ShareNumber}\");\n", + "}\n", + "\n", + "//原子替换：\n", + "//1、两个线程同时执行会输出: 0 1 或 1 0\n", + "//2、全局变量最终的值为 1" + ] + }, + { + "attachments": {}, + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## 原子比较替换 Interlocked.CompareExchange()" + ] + }, + { + "attachments": {}, + "cell_type": "markdown", + "metadata": {}, + "source": [ + "Interlocked.CompareExchange() 属于 `比较-交换` 分类, 执行时如果变量的值等于第三个变量的值，则修改为第二个变量的值并返回修改前的值；否则直接返回现有值" + ] + }, + { + "cell_type": "code", + "execution_count": null, + "metadata": { + "dotnet_interactive": { + "language": "csharp" + }, + "polyglot_notebook": { + "kernelName": "csharp" + }, + "vscode": { + "languageId": "polyglot-notebook" + } + }, + "outputs": [], + "source": [ + "//原子比较替换\n", + "public class Counter4CompareExchange\n", + "{\n", + " //共享变量\n", + " public static int ShareNumber = 0;\n", + "\n", + " //执行\n", + " public static void CompareExchange()\n", + " {\n", + " //随机休眠，打乱多线程执行顺序\n", + " Thread.Sleep(Random.Shared.Next(100,500));\n", + "\n", + " //原子操作：比较替换\n", + " int y;\n", + " while(true)\n", + " {\n", + " y = ShareNumber;\n", + " int oldShareValue = System.Threading.Interlocked.CompareExchange(ref ShareNumber,y+1,y);\n", + "\n", + " if(oldShareValue == y)\n", + " {\n", + " break;\n", + " }\n", + " }\n", + "\n", + " Console.WriteLine($\"线程[{Thread.CurrentThread.Name}] 替换前的值为 {y+1}\");\n", + " }\n", + "}\n", + "\n", + "//使用域隔离和代码折叠\n", + "{\n", + " var threads = new List()\n", + " {\n", + " new Thread(Counter4CompareExchange.CompareExchange){Name=\"thread_a\"},\n", + " new Thread(Counter4CompareExchange.CompareExchange){Name=\"thread_b\"}\n", + " };\n", + "\n", + " threads.ForEach(t => t.Start());\n", + " threads.ForEach(t => t.Join());\n", + "\n", + " //主线程信息\n", + " Console.WriteLine($\"主[执行]线程获共享变量 ShareNumber 最终的值 = {Counter4CompareExchange.ShareNumber}\");\n", + "}\n", + "\n", + "//原子替换：\n", + "//1、两个线程同时执行会输出: 1 2 或 2 1\n", + "//2、全局变量最终的值为 2" + ] + }, + { + "attachments": {}, + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## 原子读取 Interlocked.Read()" + ] + }, + { + "attachments": {}, + "cell_type": "markdown", + "metadata": {}, + "source": [ + "从内存读取值通常都是原子的，除非32位平台读取64位数据，比如32位平台上读取 long 型数值。因为32位平台读取64位数据是分高位和低位两次读取操作的，所以不是原子操作。原子读取一般会与其它原子操作配合使用。" + ] + }, + { + "cell_type": "code", + "execution_count": null, + "metadata": { + "dotnet_interactive": { + "language": "csharp" + }, + "polyglot_notebook": { + "kernelName": "csharp" + }, + "vscode": { + "languageId": "polyglot-notebook" + } + }, + "outputs": [], + "source": [ + "//原子读取\n", + "public class Counter4Read\n", + "{\n", + " //共享变量,64位数据\n", + " public static long ShareNumber = 0;\n", + "\n", + " //循环次数\n", + " public readonly static int LoopNumber = 10000;\n", + "\n", + " //一个线程循环替换数据\n", + " public static void Exchange()\n", + " {\n", + " for(int i=0; i< LoopNumber; i++)\n", + " {\n", + " System.Threading.Interlocked.Exchange(ref ShareNumber,0x7aaabbbbccccdddd);\n", + " }\n", + " }\n", + " \n", + " //一个线程循环读取\n", + " //无论多少次读取的都是 0 或者 0x7aaabbbbccccdddd\n", + " //不可能是 0x7aaabbbb00000000 或者 ccccdddd\n", + " public static void Read()\n", + " {\n", + " for(int i=0; i< LoopNumber; i++)\n", + " {\n", + " long y = System.Threading.Interlocked.Read(ref ShareNumber);\n", + "\n", + " //此条件应该永远不成立\n", + " if(y==0x7aaabbbb00000000 || y==0x00000000ccccdddd)\n", + " { \n", + " Console.WriteLine($\"线程[{System.Threading.Thread.CurrentThread.Name}], 读取到非原子值{y}\");\n", + " }\n", + " }\n", + " }\n", + "}\n", + "\n", + "//使用域隔离和代码折叠\n", + "{\n", + " var threads = new List()\n", + " {\n", + " new Thread(Counter4Read.Exchange){Name=\"thread_a\"},\n", + " new Thread(Counter4Read.Read){Name=\"thread_b\"}\n", + " };\n", + "\n", + " threads.ForEach(t => t.Start());\n", + " threads.ForEach(t => t.Join());\n", + "\n", + " //主线程信息\n", + " Console.WriteLine($\"主[执行]线程获共享变量 ShareNumber 最终的值 = {Counter4Read.ShareNumber}\");\n", + "}\n", + "\n", + "//原子读取：\n", + "//1、无论多少次读取的都是 0 或者 0x7aaabbbbccccdddd 不可能是 0x7aaabbbb00000000 或者 ccccdddd\n", + "//2、全局变量最终的值为 0x7aaabbbbccccdddd 即是 8839083633937276381 或者极概率是 0" + ] + }, + { + "attachments": {}, + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## 内存屏障 Interlocked.MemoryBarrier()" + ] + }, + { + "attachments": {}, + "cell_type": "markdown", + "metadata": {}, + "source": [ + "System.Threading.Interlocked 还提供了一些其它方法，比如内存屏障相关的 MemoryBarrier() 和 MemoryBarrierProcessWide() 和 新的 And() Or()方法等。" + ] + }, + { + "cell_type": "code", + "execution_count": null, + "metadata": { + "dotnet_interactive": { + "language": "csharp" + }, + "polyglot_notebook": { + "kernelName": "csharp" + }, + "vscode": { + "languageId": "polyglot-notebook" + } + }, + "outputs": [], + "source": [ + "/*\n", + "System.Threading.Interlocked.MemoryBarrier();\n", + "System.Threading.Interlocked.MemoryBarrierProcessWide();\n", + "System.Threading.Interlocked.And();\n", + "System.Threading.Interlocked.Or();\n", + "*/" + ] } ], "metadata": { diff --git a/MultiThreadingStudy.ConsoleApp/Program.cs b/MultiThreadingStudy.ConsoleApp/Program.cs index baf876c..b007d48 100644 --- a/MultiThreadingStudy.ConsoleApp/Program.cs +++ b/MultiThreadingStudy.ConsoleApp/Program.cs @@ -12,8 +12,9 @@ namespace MultiThreadingStudy.ConsoleApp // ThreadLocalStorage.UseDataSlot(); // ThreadLocalStorage.UseThreadStaticAttribute(); // ThreadLocalStorage.UseThreadLocalClass(); - ThreadLocalStorage.UseAsyncLocalClass(); + // ThreadLocalStorage.UseAsyncLocalClass(); + Console.WriteLine("选中的操作执行完成，主线程退出！"); } } } \ No newline at end of file