{"id":4304,"date":"2020-05-07T19:54:23","date_gmt":"2020-05-07T11:54:23","guid":{"rendered":"https:\/\/damogame.cn\/wordpress\/?p=4304"},"modified":"2020-05-07T19:54:23","modified_gmt":"2020-05-07T11:54:23","slug":"%e9%9d%9e%e9%98%bb%e5%a1%9e%e5%90%8c%e6%ad%a5%e7%ae%97%e6%b3%95%e4%b8%8ecascompare-and-swap%e6%97%a0%e9%94%81%e7%ae%97%e6%b3%95","status":"publish","type":"post","link":"https:\/\/i007.cc\/wordpress\/archives\/4304","title":{"rendered":"\u975e\u963b\u585e\u540c\u6b65\u7b97\u6cd5\u4e0eCAS(Compare and Swap)\u65e0\u9501\u7b97\u6cd5"},"content":{"rendered":"<h2><a href=\"https:\/\/www.cnblogs.com\/Mainz\/p\/3546347.html\">\u539f\u6587\u5730\u5740<\/a><\/h2>\n<p>&nbsp;<\/p>\n<div class=\"postText\">\n<div id=\"cnblogs_post_body\" class=\"blogpost-body \">\n<h4>\u9501\uff08lock\uff09\u7684\u4ee3\u4ef7<\/h4>\n<p>\u9501\u662f\u7528\u6765\u505a\u5e76\u53d1\u6700\u7b80\u5355\u7684\u65b9\u5f0f\uff0c\u5f53\u7136\u5176\u4ee3\u4ef7\u4e5f\u662f\u6700\u9ad8\u7684\u3002\u5185\u6838\u6001\u7684\u9501\u7684\u65f6\u5019\u9700\u8981\u64cd\u4f5c\u7cfb\u7edf\u8fdb\u884c\u4e00\u6b21\u4e0a\u4e0b\u6587\u5207\u6362\uff0c\u52a0\u9501\u3001\u91ca\u653e\u9501\u4f1a\u5bfc\u81f4\u6bd4\u8f83\u591a\u7684\u4e0a\u4e0b\u6587\u5207\u6362\u548c\u8c03\u5ea6\u5ef6\u65f6\uff0c\u7b49\u5f85\u9501\u7684\u7ebf\u7a0b\u4f1a\u88ab\u6302\u8d77\u76f4\u81f3\u9501\u91ca\u653e\u3002\u5728\u4e0a\u4e0b\u6587\u5207\u6362\u7684\u65f6\u5019\uff0ccpu\u4e4b\u524d\u7f13\u5b58\u7684\u6307\u4ee4\u548c\u6570\u636e\u90fd\u5c06\u5931\u6548\uff0c\u5bf9\u6027\u80fd\u6709\u5f88\u5927\u7684\u635f\u5931\u3002\u64cd\u4f5c\u7cfb\u7edf\u5bf9\u591a\u7ebf\u7a0b\u7684\u9501\u8fdb\u884c\u5224\u65ad\u5c31\u50cf\u4e24\u59d0\u59b9\u5728\u4e3a\u4e00\u4e2a\u73a9\u5177\u5728\u4e89\u5435\uff0c\u7136\u540e\u64cd\u4f5c\u7cfb\u7edf\u5c31\u662f\u80fd\u51b3\u5b9a\u4ed6\u4eec\u8c01\u80fd\u62ff\u5230\u73a9\u5177\u7684\u7236\u6bcd\uff0c\u8fd9\u662f\u5f88\u6162\u7684\u3002\u7528\u6237\u6001\u7684\u9501\u867d\u7136\u907f\u514d\u4e86\u8fd9\u4e9b\u95ee\u9898\uff0c\u4f46\u662f\u5176\u5b9e\u5b83\u4eec\u53ea\u662f\u5728\u6ca1\u6709\u771f\u5b9e\u7684\u7ade\u4e89\u65f6\u624d\u6709\u6548\u3002<\/p>\n<p>Java\u5728JDK1.5\u4e4b\u524d\u90fd\u662f\u9760synchronized\u5173\u952e\u5b57\u4fdd\u8bc1\u540c\u6b65\u7684\uff0c\u8fd9\u79cd\u901a\u8fc7\u4f7f\u7528\u4e00\u81f4\u7684\u9501\u5b9a\u534f\u8bae\u6765\u534f\u8c03\u5bf9\u5171\u4eab\u72b6\u6001\u7684\u8bbf\u95ee\uff0c\u53ef\u4ee5\u786e\u4fdd\u65e0\u8bba\u54ea\u4e2a\u7ebf\u7a0b\u6301\u6709\u5b88\u62a4\u53d8\u91cf\u7684\u9501\uff0c\u90fd\u91c7\u7528\u72ec\u5360\u7684\u65b9\u5f0f\u6765\u8bbf\u95ee\u8fd9\u4e9b\u53d8\u91cf\uff0c\u5982\u679c\u51fa\u73b0\u591a\u4e2a\u7ebf\u7a0b\u540c\u65f6\u8bbf\u95ee\u9501\uff0c\u90a3\u7b2c\u4e00\u4e9b\u7ebf\u7ebf\u7a0b\u5c06\u88ab\u6302\u8d77\uff0c\u5f53\u7ebf\u7a0b\u6062\u590d\u6267\u884c\u65f6\uff0c\u5fc5\u987b\u7b49\u5f85\u5176\u5b83\u7ebf\u7a0b\u6267\u884c\u5b8c\u4ed6\u4eec\u7684\u65f6\u95f4\u7247\u4ee5\u540e\u624d\u80fd\u88ab\u8c03\u5ea6\u6267\u884c\uff0c\u5728\u6302\u8d77\u548c\u6062\u590d\u6267\u884c\u8fc7\u7a0b\u4e2d\u5b58\u5728\u7740\u5f88\u5927\u7684\u5f00\u9500\u3002\u9501\u8fd8\u5b58\u5728\u7740\u5176\u5b83\u4e00\u4e9b\u7f3a\u70b9\uff0c\u5f53\u4e00\u4e2a\u7ebf\u7a0b\u6b63\u5728\u7b49\u5f85\u9501\u65f6\uff0c\u5b83\u4e0d\u80fd\u505a\u4efb\u4f55\u4e8b\u3002\u5982\u679c\u4e00\u4e2a\u7ebf\u7a0b\u5728\u6301\u6709\u9501\u7684\u60c5\u51b5\u4e0b\u88ab\u5ef6\u8fdf\u6267\u884c\uff0c\u90a3\u4e48\u6240\u6709\u9700\u8981\u8fd9\u4e2a\u9501\u7684\u7ebf\u7a0b\u90fd\u65e0\u6cd5\u6267\u884c\u4e0b\u53bb\u3002\u5982\u679c\u88ab\u963b\u585e\u7684\u7ebf\u7a0b\u4f18\u5148\u7ea7\u9ad8\uff0c\u800c\u6301\u6709\u9501\u7684\u7ebf\u7a0b\u4f18\u5148\u7ea7\u4f4e\uff0c\u5c06\u4f1a\u5bfc\u81f4\u4f18\u5148\u7ea7\u53cd\u8f6c(Priority Inversion)\u3002<\/p>\n<h4>\u4e50\u89c2\u9501\u4e0e\u60b2\u89c2\u9501<\/h4>\n<p>\u72ec\u5360\u9501\u662f\u4e00\u79cd\u60b2\u89c2\u9501\uff0csynchronized\u5c31\u662f\u4e00\u79cd\u72ec\u5360\u9501\uff0c\u5b83\u5047\u8bbe\u6700\u574f\u7684\u60c5\u51b5\uff0c\u5e76\u4e14\u53ea\u6709\u5728\u786e\u4fdd\u5176\u5b83\u7ebf\u7a0b\u4e0d\u4f1a\u9020\u6210\u5e72\u6270\u7684\u60c5\u51b5\u4e0b\u6267\u884c\uff0c\u4f1a\u5bfc\u81f4\u5176\u5b83\u6240\u6709\u9700\u8981\u9501\u7684\u7ebf\u7a0b\u6302\u8d77\uff0c\u7b49\u5f85\u6301\u6709\u9501\u7684\u7ebf\u7a0b\u91ca\u653e\u9501\u3002\u800c\u53e6\u4e00\u4e2a\u66f4\u52a0\u6709\u6548\u7684\u9501\u5c31\u662f\u4e50\u89c2\u9501\u3002\u6240\u8c13\u4e50\u89c2\u9501\u5c31\u662f\uff0c\u6bcf\u6b21\u4e0d\u52a0\u9501\u800c\u662f\u5047\u8bbe\u6ca1\u6709\u51b2\u7a81\u800c\u53bb\u5b8c\u6210\u67d0\u9879\u64cd\u4f5c\uff0c\u5982\u679c\u56e0\u4e3a\u51b2\u7a81\u5931\u8d25\u5c31\u91cd\u8bd5\uff0c\u76f4\u5230\u6210\u529f\u4e3a\u6b62\u3002<\/p>\n<h4>volatile\u7684\u95ee\u9898<\/h4>\n<p>\u4e0e\u9501\u76f8\u6bd4\uff0cvolatile\u53d8\u91cf\u662f\u4e00\u548c\u66f4\u8f7b\u91cf\u7ea7\u7684\u540c\u6b65\u673a\u5236\uff0c\u56e0\u4e3a\u5728\u4f7f\u7528\u8fd9\u4e9b\u53d8\u91cf\u65f6\u4e0d\u4f1a\u53d1\u751f\u4e0a\u4e0b\u6587\u5207\u6362\u548c\u7ebf\u7a0b\u8c03\u5ea6\u7b49\u64cd\u4f5c\uff0c\u4f46\u662fvolatile\u53d8\u91cf\u4e5f\u5b58\u5728\u4e00\u4e9b\u5c40\u9650\uff1a\u4e0d\u80fd\u7528\u4e8e\u6784\u5efa\u539f\u5b50\u7684\u590d\u5408\u64cd\u4f5c\uff0c\u56e0\u6b64\u5f53\u4e00\u4e2a\u53d8\u91cf\u4f9d\u8d56\u65e7\u503c\u65f6\u5c31\u4e0d\u80fd\u4f7f\u7528volatile\u53d8\u91cf\u3002\uff08\u53c2\u8003\uff1a<a href=\"http:\/\/www.cnblogs.com\/lucifer1982\/archive\/2008\/03\/23\/1116981.html\" target=\"_blank\" rel=\"noopener noreferrer\">\u8c08\u8c08volatiile<\/a>\uff09<\/p>\n<p><strong>volatile\u53ea\u80fd\u4fdd\u8bc1\u53d8\u91cf\u5bf9\u5404\u4e2a\u7ebf\u7a0b\u7684\u53ef\u89c1\u6027\uff0c\u4f46\u4e0d\u80fd\u4fdd\u8bc1\u539f\u5b50\u6027<\/strong>\u3002\u4e3a\u4ec0\u4e48\uff1f\u89c1\u6211\u7684\u53e6\u5916\u4e00\u7bc7\u6587\u7ae0\uff1a\u300a<a href=\"http:\/\/www.cnblogs.com\/Mainz\/p\/3556430.html\" target=\"_blank\" rel=\"noopener noreferrer\">\u4e3a\u4ec0\u4e48volatile\u4e0d\u80fd\u4fdd\u8bc1\u539f\u5b50\u6027\u800cAtomic\u53ef\u4ee5\uff1f<\/a>\u300b<\/p>\n<h4>Java\u4e2d\u7684\u539f\u5b50\u64cd\u4f5c( atomic operations)<\/h4>\n<p>\u539f\u5b50\u64cd\u4f5c\u6307\u7684\u662f\u5728\u4e00\u6b65\u4e4b\u5185\u5c31\u5b8c\u6210\u800c\u4e14\u4e0d\u80fd\u88ab\u4e2d\u65ad\u3002\u539f\u5b50\u64cd\u4f5c\u5728\u591a\u7ebf\u7a0b\u73af\u5883\u4e2d\u662f\u7ebf\u7a0b\u5b89\u5168\u7684\uff0c\u65e0\u9700\u8003\u8651\u540c\u6b65\u7684\u95ee\u9898\u3002\u5728java\u4e2d\uff0c\u4e0b\u5217\u64cd\u4f5c\u662f\u539f\u5b50\u64cd\u4f5c\uff1a<\/p>\n<ul>\n<li>all assignments of primitive types except for long and double<\/li>\n<li>all assignments of references<\/li>\n<li>all operations of java.concurrent.Atomic* classes<\/li>\n<li>all assignments to volatile longs and doubles<\/li>\n<\/ul>\n<p>\u95ee\u9898\u6765\u4e86\uff0c\u4e3a\u4ec0\u4e48long\u578b\u8d4b\u503c\u4e0d\u662f\u539f\u5b50\u64cd\u4f5c\u5462\uff1f\u4f8b\u5982\uff1a<\/p>\n<div>\n<div id=\"highlighter_774997\" class=\"syntaxhighlighter  java\">\n<table border=\"0\" cellspacing=\"0\" cellpadding=\"0\">\n<tbody>\n<tr>\n<td class=\"gutter\">\n<div class=\"line number1 index0 alt2\">1<\/div>\n<\/td>\n<td class=\"code\">\n<div class=\"container\">\n<div class=\"line number1 index0 alt2\"><code class=\"java keyword\">long<\/code>\u00a0<code class=\"java plain\">foo = 65465498L;<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<p>\u5b9e\u65f6\u4e0ajava\u4f1a\u5206\u4e24\u6b65\u5199\u5165\u8fd9\u4e2along\u53d8\u91cf\uff0c\u5148\u519932\u4f4d\uff0c\u518d\u5199\u540e32\u4f4d\u3002\u8fd9\u6837\u5c31\u7ebf\u7a0b\u4e0d\u5b89\u5168\u4e86\u3002\u5982\u679c\u6539\u6210\u4e0b\u9762\u7684\u5c31\u7ebf\u7a0b\u5b89\u5168\u4e86\uff1a<\/p>\n<div>\n<div id=\"highlighter_209173\" class=\"syntaxhighlighter  java\">\n<table border=\"0\" cellspacing=\"0\" cellpadding=\"0\">\n<tbody>\n<tr>\n<td class=\"gutter\">\n<div class=\"line number1 index0 alt2\">1<\/div>\n<\/td>\n<td class=\"code\">\n<div class=\"container\">\n<div class=\"line number1 index0 alt2\"><code class=\"java keyword\">private<\/code>\u00a0<code class=\"java keyword\">volatile<\/code>\u00a0<code class=\"java keyword\">long<\/code>\u00a0<code class=\"java plain\">foo;<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<p>\u56e0\u4e3avolatile\u5185\u90e8\u5df2\u7ecf\u505a\u4e86synchronized.<\/p>\n<h4>CAS\u65e0\u9501\u7b97\u6cd5<\/h4>\n<p>\u8981\u5b9e\u73b0\u65e0\u9501\uff08lock-free\uff09\u7684\u975e\u963b\u585e\u7b97\u6cd5\u6709\u591a\u79cd\u5b9e\u73b0\u65b9\u6cd5\uff0c\u5176\u4e2d<a href=\"http:\/\/en.wikipedia.org\/wiki\/Compare-and-swap\" target=\"_blank\" rel=\"noopener noreferrer\">CAS\uff08\u6bd4\u8f83\u4e0e\u4ea4\u6362\uff0cCompare and swap\uff09<\/a>\u662f\u4e00\u79cd\u6709\u540d\u7684\u65e0\u9501\u7b97\u6cd5\u3002CAS, CPU\u6307\u4ee4\uff0c\u5728\u5927\u591a\u6570\u5904\u7406\u5668\u67b6\u6784\uff0c\u5305\u62ecIA32\u3001Space\u4e2d\u91c7\u7528\u7684\u90fd\u662fCAS\u6307\u4ee4\uff0cCAS\u7684\u8bed\u4e49\u662f\u201c\u6211\u8ba4\u4e3aV\u7684\u503c\u5e94\u8be5\u4e3aA\uff0c\u5982\u679c\u662f\uff0c\u90a3\u4e48\u5c06V\u7684\u503c\u66f4\u65b0\u4e3aB\uff0c\u5426\u5219\u4e0d\u4fee\u6539\u5e76\u544a\u8bc9V\u7684\u503c\u5b9e\u9645\u4e3a\u591a\u5c11\u201d\uff0cCAS\u662f\u9879<strong>\u4e50\u89c2\u9501<\/strong>\u6280\u672f\uff0c\u5f53\u591a\u4e2a\u7ebf\u7a0b\u5c1d\u8bd5\u4f7f\u7528CAS\u540c\u65f6\u66f4\u65b0\u540c\u4e00\u4e2a\u53d8\u91cf\u65f6\uff0c\u53ea\u6709\u5176\u4e2d\u4e00\u4e2a\u7ebf\u7a0b\u80fd\u66f4\u65b0\u53d8\u91cf\u7684\u503c\uff0c\u800c\u5176\u5b83\u7ebf\u7a0b\u90fd\u5931\u8d25\uff0c\u5931\u8d25\u7684\u7ebf\u7a0b\u5e76\u4e0d\u4f1a\u88ab\u6302\u8d77\uff0c\u800c\u662f\u88ab\u544a\u77e5\u8fd9\u6b21\u7ade\u4e89\u4e2d\u5931\u8d25\uff0c\u5e76\u53ef\u4ee5\u518d\u6b21\u5c1d\u8bd5\u3002CAS\u67093\u4e2a\u64cd\u4f5c\u6570\uff0c\u5185\u5b58\u503cV\uff0c\u65e7\u7684\u9884\u671f\u503cA\uff0c\u8981\u4fee\u6539\u7684\u65b0\u503cB\u3002\u5f53\u4e14\u4ec5\u5f53\u9884\u671f\u503cA\u548c\u5185\u5b58\u503cV\u76f8\u540c\u65f6\uff0c\u5c06\u5185\u5b58\u503cV\u4fee\u6539\u4e3aB\uff0c\u5426\u5219\u4ec0\u4e48\u90fd\u4e0d\u505a\u3002CAS\u65e0\u9501\u7b97\u6cd5\u7684C\u5b9e\u73b0\u5982\u4e0b\uff1a<\/p>\n<div>\n<div id=\"highlighter_786276\" class=\"syntaxhighlighter  csharp\">\n<table border=\"0\" cellspacing=\"0\" cellpadding=\"0\">\n<tbody>\n<tr>\n<td class=\"gutter\">\n<div class=\"line number1 index0 alt2\">1<\/div>\n<div class=\"line number2 index1 alt1\">2<\/div>\n<div class=\"line number3 index2 alt2\">3<\/div>\n<div class=\"line number4 index3 alt1\">4<\/div>\n<div class=\"line number5 index4 alt2\">5<\/div>\n<div class=\"line number6 index5 alt1\">6<\/div>\n<div class=\"line number7 index6 alt2\">7<\/div>\n<div class=\"line number8 index7 alt1\">8<\/div>\n<div class=\"line number9 index8 alt2\">9<\/div>\n<\/td>\n<td class=\"code\">\n<div class=\"container\">\n<div class=\"line number1 index0 alt2\"><code class=\"csharp keyword\">int<\/code>\u00a0<code class=\"csharp plain\">compare_and_swap (<\/code><code class=\"csharp keyword\">int<\/code><code class=\"csharp plain\">* reg, <\/code><code class=\"csharp keyword\">int<\/code>\u00a0<code class=\"csharp plain\">oldval, <\/code><code class=\"csharp keyword\">int<\/code>\u00a0<code class=\"csharp plain\">newval) <\/code><\/div>\n<div class=\"line number2 index1 alt1\"><code class=\"csharp plain\">{<\/code><\/div>\n<div class=\"line number3 index2 alt2\"><code class=\"csharp spaces\">\u00a0\u00a0<\/code><code class=\"csharp plain\">ATOMIC();<\/code><\/div>\n<div class=\"line number4 index3 alt1\"><code class=\"csharp spaces\">\u00a0\u00a0<\/code><code class=\"csharp keyword\">int<\/code>\u00a0<code class=\"csharp plain\">old_reg_val = *reg;<\/code><\/div>\n<div class=\"line number5 index4 alt2\"><code class=\"csharp spaces\">\u00a0\u00a0<\/code><code class=\"csharp keyword\">if<\/code>\u00a0<code class=\"csharp plain\">(old_reg_val == oldval) <\/code><\/div>\n<div class=\"line number6 index5 alt1\"><code class=\"csharp spaces\">\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"csharp plain\">*reg = newval;<\/code><\/div>\n<div class=\"line number7 index6 alt2\"><code class=\"csharp spaces\">\u00a0\u00a0<\/code><code class=\"csharp plain\">END_ATOMIC();<\/code><\/div>\n<div class=\"line number8 index7 alt1\"><code class=\"csharp spaces\">\u00a0\u00a0<\/code><code class=\"csharp keyword\">return<\/code>\u00a0<code class=\"csharp plain\">old_reg_val;<\/code><\/div>\n<div class=\"line number9 index8 alt2\"><code class=\"csharp plain\">}<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<h4>CAS\uff08\u4e50\u89c2\u9501\u7b97\u6cd5\uff09\u7684\u57fa\u672c\u5047\u8bbe\u524d\u63d0<\/h4>\n<p>CAS\u6bd4\u8f83\u4e0e\u4ea4\u6362\u7684\u4f2a\u4ee3\u7801\u53ef\u4ee5\u8868\u793a\u4e3a\uff1a<\/p>\n<p>do{<br \/>\n\u5907\u4efd\u65e7\u6570\u636e\uff1b<br \/>\n\u57fa\u4e8e\u65e7\u6570\u636e\u6784\u9020\u65b0\u6570\u636e\uff1b<br \/>\n}while(!CAS( \u5185\u5b58\u5730\u5740\uff0c\u5907\u4efd\u7684\u65e7\u6570\u636e\uff0c\u65b0\u6570\u636e ))<\/p>\n<p><a href=\"https:\/\/images0.cnblogs.com\/blog\/28306\/201402\/191145372245230.png\"><img loading=\"lazy\" decoding=\"async\" title=\"ConcurrencyCAS\" src=\"https:\/\/images0.cnblogs.com\/blog\/28306\/201402\/191145387966044.png\" alt=\"ConcurrencyCAS\" width=\"320\" height=\"171\" border=\"0\" \/><\/a><\/p>\n<p>\uff08\u4e0a\u56fe\u7684\u89e3\u91ca\uff1aCPU\u53bb\u66f4\u65b0\u4e00\u4e2a\u503c\uff0c\u4f46\u5982\u679c\u60f3\u6539\u7684\u503c\u4e0d\u518d\u662f\u539f\u6765\u7684\u503c\uff0c\u64cd\u4f5c\u5c31\u5931\u8d25\uff0c\u56e0\u4e3a\u5f88\u660e\u663e\uff0c\u6709\u5176\u5b83\u64cd\u4f5c\u5148\u6539\u53d8\u4e86\u8fd9\u4e2a\u503c\u3002\uff09<\/p>\n<p>\u5c31\u662f\u6307\u5f53\u4e24\u8005\u8fdb\u884c\u6bd4\u8f83\u65f6\uff0c\u5982\u679c\u76f8\u7b49\uff0c\u5219\u8bc1\u660e\u5171\u4eab\u6570\u636e\u6ca1\u6709\u88ab\u4fee\u6539\uff0c\u66ff\u6362\u6210\u65b0\u503c\uff0c\u7136\u540e\u7ee7\u7eed\u5f80\u4e0b\u8fd0\u884c\uff1b\u5982\u679c\u4e0d\u76f8\u7b49\uff0c\u8bf4\u660e\u5171\u4eab\u6570\u636e\u5df2\u7ecf\u88ab\u4fee\u6539\uff0c\u653e\u5f03\u5df2\u7ecf\u6240\u505a\u7684\u64cd\u4f5c\uff0c\u7136\u540e\u91cd\u65b0\u6267\u884c\u521a\u624d\u7684\u64cd\u4f5c\u3002\u5bb9\u6613\u770b\u51fa CAS \u64cd\u4f5c\u662f\u57fa\u4e8e\u5171\u4eab\u6570\u636e\u4e0d\u4f1a\u88ab\u4fee\u6539\u7684\u5047\u8bbe\uff0c\u91c7\u7528\u4e86\u7c7b\u4f3c\u4e8e\u6570\u636e\u5e93\u7684 commit-retry \u7684\u6a21\u5f0f\u3002\u5f53\u540c\u6b65\u51b2\u7a81\u51fa\u73b0\u7684\u673a\u4f1a\u5f88\u5c11\u65f6\uff0c\u8fd9\u79cd\u5047\u8bbe\u80fd\u5e26\u6765\u8f83\u5927\u7684\u6027\u80fd\u63d0\u5347\u3002<\/p>\n<h4>CAS\u7684\u5f00\u9500\uff08CPU Cache Miss problem\uff09<\/h4>\n<p>\u524d\u9762\u8bf4\u8fc7\u4e86\uff0cCAS\uff08\u6bd4\u8f83\u5e76\u4ea4\u6362\uff09\u662fCPU\u6307\u4ee4\u7ea7\u7684\u64cd\u4f5c\uff0c\u53ea\u6709\u4e00\u6b65\u539f\u5b50\u64cd\u4f5c\uff0c\u6240\u4ee5\u975e\u5e38\u5feb\u3002\u800c\u4e14CAS\u907f\u514d\u4e86\u8bf7\u6c42\u64cd\u4f5c\u7cfb\u7edf\u6765\u88c1\u5b9a\u9501\u7684\u95ee\u9898\uff0c\u4e0d\u7528\u9ebb\u70e6\u64cd\u4f5c\u7cfb\u7edf\uff0c\u76f4\u63a5\u5728CPU\u5185\u90e8\u5c31\u641e\u5b9a\u4e86\u3002\u4f46CAS\u5c31\u6ca1\u6709\u5f00\u9500\u4e86\u5417\uff1f\u4e0d\uff01\u6709cache miss\u7684\u60c5\u51b5\u3002\u8fd9\u4e2a\u95ee\u9898\u6bd4\u8f83\u590d\u6742\uff0c\u9996\u5148\u9700\u8981\u4e86\u89e3CPU\u7684\u786c\u4ef6\u4f53\u7cfb\u7ed3\u6784\uff1a<\/p>\n<p><a href=\"https:\/\/images0.cnblogs.com\/blog\/28306\/201402\/191145402051274.png\"><img loading=\"lazy\" decoding=\"async\" title=\"2014-02-19_11h35_45\" src=\"https:\/\/images0.cnblogs.com\/blog\/28306\/201402\/191145414444218.png\" alt=\"2014-02-19_11h35_45\" width=\"562\" height=\"480\" border=\"0\" \/><\/a><\/p>\n<p>\u4e0a\u56fe\u53ef\u4ee5\u770b\u5230\u4e00\u4e2a8\u6838CPU\u8ba1\u7b97\u673a\u7cfb\u7edf\uff0c\u6bcf\u4e2aCPU\u6709cache\uff08CPU\u5185\u90e8\u7684\u9ad8\u901f\u7f13\u5b58\uff0c\u5bc4\u5b58\u5668\uff09\uff0c\u7ba1\u82af\u5185\u8fd8\u5e26\u6709\u4e00\u4e2a\u4e92\u8054\u6a21\u5757\uff0c\u4f7f\u7ba1\u82af\u5185\u7684\u4e24\u4e2a\u6838\u53ef\u4ee5\u4e92\u76f8\u901a\u4fe1\u3002\u5728\u56fe\u4e2d\u592e\u7684\u7cfb\u7edf\u4e92\u8054\u6a21\u5757\u53ef\u4ee5\u8ba9\u56db\u4e2a\u7ba1\u82af\u76f8\u4e92\u901a\u4fe1\uff0c\u5e76\u4e14\u5c06\u7ba1\u82af\u4e0e\u4e3b\u5b58\u8fde\u63a5\u8d77\u6765\u3002\u6570\u636e\u4ee5\u201c\u7f13\u5b58\u7ebf\u201d\u4e3a\u5355\u4f4d\u5728\u7cfb\u7edf\u4e2d\u4f20\u8f93\uff0c\u201c\u7f13\u5b58\u7ebf\u201d\u5bf9\u5e94\u4e8e\u5185\u5b58\u4e2d\u4e00\u4e2a 2 \u7684\u5e42\u5927\u5c0f\u7684\u5b57\u8282\u5757\uff0c\u5927\u5c0f\u901a\u5e38\u4e3a 32 \u5230 256 \u5b57\u8282\u4e4b\u95f4\u3002\u5f53 CPU \u4ece\u5185\u5b58\u4e2d\u8bfb\u53d6\u4e00\u4e2a\u53d8\u91cf\u5230\u5b83\u7684\u5bc4\u5b58\u5668\u4e2d\u65f6\uff0c\u5fc5\u987b\u9996\u5148\u5c06\u5305\u542b\u4e86\u8be5\u53d8\u91cf\u7684\u7f13\u5b58\u7ebf\u8bfb\u53d6\u5230 CPU \u9ad8\u901f\u7f13\u5b58\u3002\u540c\u6837\u5730\uff0cCPU \u5c06\u5bc4\u5b58\u5668\u4e2d\u7684\u4e00\u4e2a\u503c\u5b58\u50a8\u5230\u5185\u5b58\u65f6\uff0c\u4e0d\u4ec5\u5fc5\u987b\u5c06\u5305\u542b\u4e86\u8be5\u503c\u7684\u7f13\u5b58\u7ebf\u8bfb\u5230 CPU \u9ad8\u901f\u7f13\u5b58\uff0c\u8fd8\u5fc5\u987b\u786e\u4fdd\u6ca1\u6709\u5176\u4ed6 CPU \u62e5\u6709\u8be5\u7f13\u5b58\u7ebf\u7684\u62f7\u8d1d\u3002<\/p>\n<p>\u6bd4\u5982\uff0c\u5982\u679c CPU0 \u5728\u5bf9\u4e00\u4e2a\u53d8\u91cf\u6267\u884c\u201c\u6bd4\u8f83\u5e76\u4ea4\u6362\u201d\uff08CAS\uff09\u64cd\u4f5c\uff0c\u800c\u8be5\u53d8\u91cf\u6240\u5728\u7684\u7f13\u5b58\u7ebf\u5728 CPU7 \u7684\u9ad8\u901f\u7f13\u5b58\u4e2d\uff0c\u5c31\u4f1a\u53d1\u751f\u4ee5\u4e0b\u7ecf\u8fc7\u7b80\u5316\u7684\u4e8b\u4ef6\u5e8f\u5217\uff1a<\/p>\n<ul>\n<li>CPU0 \u68c0\u67e5\u672c\u5730\u9ad8\u901f\u7f13\u5b58\uff0c\u6ca1\u6709\u627e\u5230\u7f13\u5b58\u7ebf\u3002<\/li>\n<li>\u8bf7\u6c42\u88ab\u8f6c\u53d1\u5230 CPU0 \u548c CPU1 \u7684\u4e92\u8054\u6a21\u5757\uff0c\u68c0\u67e5 CPU1 \u7684\u672c\u5730\u9ad8\u901f\u7f13\u5b58\uff0c\u6ca1\u6709\u627e\u5230\u7f13\u5b58\u7ebf\u3002<\/li>\n<li>\u8bf7\u6c42\u88ab\u8f6c\u53d1\u5230\u7cfb\u7edf\u4e92\u8054\u6a21\u5757\uff0c\u68c0\u67e5\u5176\u4ed6\u4e09\u4e2a\u7ba1\u82af\uff0c\u5f97\u77e5\u7f13\u5b58\u7ebf\u88ab CPU6\u548c CPU7 \u6240\u5728\u7684\u7ba1\u82af\u6301\u6709\u3002<\/li>\n<li>\u8bf7\u6c42\u88ab\u8f6c\u53d1\u5230 CPU6 \u548c CPU7 \u7684\u4e92\u8054\u6a21\u5757\uff0c\u68c0\u67e5\u8fd9\u4e24\u4e2a CPU \u7684\u9ad8\u901f\u7f13\u5b58\uff0c\u5728 CPU7 \u7684\u9ad8\u901f\u7f13\u5b58\u4e2d\u627e\u5230\u7f13\u5b58\u7ebf\u3002<\/li>\n<li>CPU7 \u5c06\u7f13\u5b58\u7ebf\u53d1\u9001\u7ed9\u6240\u5c5e\u7684\u4e92\u8054\u6a21\u5757\uff0c\u5e76\u4e14\u5237\u65b0\u81ea\u5df1\u9ad8\u901f\u7f13\u5b58\u4e2d\u7684\u7f13\u5b58\u7ebf\u3002<\/li>\n<li>CPU6 \u548c CPU7 \u7684\u4e92\u8054\u6a21\u5757\u5c06\u7f13\u5b58\u7ebf\u53d1\u9001\u7ed9\u7cfb\u7edf\u4e92\u8054\u6a21\u5757\u3002<\/li>\n<li>\u7cfb\u7edf\u4e92\u8054\u6a21\u5757\u5c06\u7f13\u5b58\u7ebf\u53d1\u9001\u7ed9 CPU0 \u548c CPU1 \u7684\u4e92\u8054\u6a21\u5757\u3002<\/li>\n<li>CPU0 \u548c CPU1 \u7684\u4e92\u8054\u6a21\u5757\u5c06\u7f13\u5b58\u7ebf\u53d1\u9001\u7ed9 CPU0 \u7684\u9ad8\u901f\u7f13\u5b58\u3002<\/li>\n<li>CPU0 \u73b0\u5728\u53ef\u4ee5\u5bf9\u9ad8\u901f\u7f13\u5b58\u4e2d\u7684\u53d8\u91cf\u6267\u884c CAS \u64cd\u4f5c\u4e86<\/li>\n<\/ul>\n<p>\u4ee5\u4e0a\u662f\u5237\u65b0\u4e0d\u540cCPU\u7f13\u5b58\u7684\u5f00\u9500\u3002\u6700\u597d\u60c5\u51b5\u4e0b\u7684 CAS \u64cd\u4f5c\u6d88\u8017\u5927\u6982 40 \u7eb3\u79d2\uff0c\u8d85\u8fc7 60 \u4e2a\u65f6\u949f\u5468\u671f\u3002\u8fd9\u91cc\u7684\u201c\u6700\u597d\u60c5\u51b5\u201d\u662f\u6307\u5bf9\u67d0\u4e00\u4e2a\u53d8\u91cf\u6267\u884c CAS \u64cd\u4f5c\u7684 CPU \u6b63\u597d\u662f\u6700\u540e\u4e00\u4e2a\u64cd\u4f5c\u8be5\u53d8\u91cf\u7684CPU\uff0c\u6240\u4ee5\u5bf9\u5e94\u7684\u7f13\u5b58\u7ebf\u5df2\u7ecf\u5728 CPU \u7684\u9ad8\u901f\u7f13\u5b58\u4e2d\u4e86\uff0c\u7c7b\u4f3c\u5730\uff0c\u6700\u597d\u60c5\u51b5\u4e0b\u7684\u9501\u64cd\u4f5c\uff08\u4e00\u4e2a\u201cround trip \u5bf9\u201d\u5305\u62ec\u83b7\u53d6\u9501\u548c\u968f\u540e\u7684\u91ca\u653e\u9501\uff09\u6d88\u8017\u8d85\u8fc7 60 \u7eb3\u79d2\uff0c\u8d85\u8fc7 100 \u4e2a\u65f6\u949f\u5468\u671f\u3002\u8fd9\u91cc\u7684\u201c\u6700\u597d\u60c5\u51b5\u201d\u610f\u5473\u7740\u7528\u4e8e\u8868\u793a\u9501\u7684\u6570\u636e\u7ed3\u6784\u5df2\u7ecf\u5728\u83b7\u53d6\u548c\u91ca\u653e\u9501\u7684 CPU \u6240\u5c5e\u7684\u9ad8\u901f\u7f13\u5b58\u4e2d\u4e86\u3002\u9501\u64cd\u4f5c\u6bd4 CAS \u64cd\u4f5c\u66f4\u52a0\u8017\u65f6\uff0c\u662f\u56e0\u6df1\u5165\u7406\u89e3\u5e76\u884c\u7f16\u7a0b<br \/>\n\u4e3a\u9501\u64cd\u4f5c\u7684\u6570\u636e\u7ed3\u6784\u4e2d\u9700\u8981\u4e24\u4e2a\u539f\u5b50\u64cd\u4f5c\u3002\u7f13\u5b58\u672a\u547d\u4e2d\u6d88\u8017\u5927\u6982 140 \u7eb3\u79d2\uff0c\u8d85\u8fc7 200 \u4e2a\u65f6\u949f\u5468\u671f\u3002\u9700\u8981\u5728\u5b58\u50a8\u65b0\u503c\u65f6\u67e5\u8be2\u53d8\u91cf\u7684\u65e7\u503c\u7684 CAS \u64cd\u4f5c\uff0c\u6d88\u8017\u5927\u6982 300 \u7eb3\u79d2\uff0c\u8d85\u8fc7 500 \u4e2a\u65f6\u949f\u5468\u671f\u3002\u60f3\u60f3\u8fd9\u4e2a\uff0c\u5728\u6267\u884c\u4e00\u6b21 CAS \u64cd\u4f5c\u7684\u65f6\u95f4\u91cc\uff0cCPU \u53ef\u4ee5\u6267\u884c 500 \u6761\u666e\u901a\u6307\u4ee4\u3002\u8fd9\u8868\u660e\u4e86\u7ec6\u7c92\u5ea6\u9501\u7684\u5c40\u9650\u6027\u3002<\/p>\n<p>\u4ee5\u4e0b\u662fcache miss cas \u548clock\u7684\u6027\u80fd\u5bf9\u6bd4\uff1a<\/p>\n<p><a href=\"https:\/\/images0.cnblogs.com\/blog\/28306\/201402\/191145426722461.png\"><img loading=\"lazy\" decoding=\"async\" title=\"2014-02-19_11h43_23\" src=\"https:\/\/images0.cnblogs.com\/blog\/28306\/201402\/191145436475092.png\" alt=\"2014-02-19_11h43_23\" width=\"320\" height=\"224\" border=\"0\" \/><\/a><\/p>\n<h4>JVM\u5bf9CAS\u7684\u652f\u6301\uff1aAtomicInt, AtomicLong.incrementAndGet()<\/h4>\n<p>\u5728JDK1.5\u4e4b\u524d\uff0c\u5982\u679c\u4e0d\u7f16\u5199\u660e\u786e\u7684\u4ee3\u7801\u5c31\u65e0\u6cd5\u6267\u884cCAS\u64cd\u4f5c\uff0c\u5728JDK1.5\u4e2d\u5f15\u5165\u4e86\u5e95\u5c42\u7684\u652f\u6301\uff0c\u5728int\u3001long\u548c\u5bf9\u8c61\u7684\u5f15\u7528\u7b49\u7c7b\u578b\u4e0a\u90fd\u516c\u5f00\u4e86CAS\u7684\u64cd\u4f5c\uff0c\u5e76\u4e14JVM\u628a\u5b83\u4eec\u7f16\u8bd1\u4e3a\u5e95\u5c42\u786c\u4ef6\u63d0\u4f9b\u7684\u6700\u6709\u6548\u7684\u65b9\u6cd5\uff0c\u5728\u8fd0\u884cCAS\u7684\u5e73\u53f0\u4e0a\uff0c\u8fd0\u884c\u65f6\u628a\u5b83\u4eec\u7f16\u8bd1\u4e3a\u76f8\u5e94\u7684\u673a\u5668\u6307\u4ee4\uff0c\u5982\u679c\u5904\u7406\u5668\/CPU\u4e0d\u652f\u6301CAS\u6307\u4ee4\uff0c\u90a3\u4e48JVM\u5c06\u4f7f\u7528\u81ea\u65cb\u9501\u3002\u56e0\u6b64\uff0c\u503c\u5f97\u6ce8\u610f\u7684\u662f\uff0c<strong>CAS\u89e3\u51b3\u65b9\u6848\u4e0e\u5e73\u53f0\/\u7f16\u8bd1\u5668\u7d27\u5bc6\u76f8\u5173\uff08\u6bd4\u5982x86\u67b6\u6784\u4e0b\u5176\u5bf9\u5e94\u7684\u6c47\u7f16\u6307\u4ee4\u662flock cmpxchg\uff0c\u5982\u679c\u60f3\u898164Bit\u7684\u4ea4\u6362\uff0c\u5219\u5e94\u4f7f\u7528lock cmpxchg8b\u3002\u5728.NET\u4e2d\u6211\u4eec\u53ef\u4ee5\u4f7f\u7528Interlocked.CompareExchange\u51fd\u6570\uff09<\/strong>\u3002<\/p>\n<p>\u5728\u539f\u5b50\u7c7b\u53d8\u91cf\u4e2d\uff0c\u5982java.util.concurrent.atomic\u4e2d\u7684AtomicXXX\uff0c\u90fd\u4f7f\u7528\u4e86\u8fd9\u4e9b\u5e95\u5c42\u7684JVM\u652f\u6301\u4e3a\u6570\u5b57\u7c7b\u578b\u7684\u5f15\u7528\u7c7b\u578b\u63d0\u4f9b\u4e00\u79cd\u9ad8\u6548\u7684CAS\u64cd\u4f5c\uff0c\u800c\u5728java.util.concurrent\u4e2d\u7684\u5927\u591a\u6570\u7c7b\u5728\u5b9e\u73b0\u65f6\u90fd\u76f4\u63a5\u6216\u95f4\u63a5\u7684\u4f7f\u7528\u4e86\u8fd9\u4e9b\u539f\u5b50\u53d8\u91cf\u7c7b\u3002<\/p>\n<p>Java 1.6\u4e2dAtomicLong.incrementAndGet()\u7684\u5b9e\u73b0\u6e90\u7801\u4e3a\uff1a<\/p>\n<div>\n<div id=\"highlighter_5509\" class=\"syntaxhighlighter collapsed  java\">\n<div class=\"toolbar\"><a class=\"toolbar_item command_expandSource expandSource\" href=\"https:\/\/www.cnblogs.com\/Mainz\/p\/3546347.html#\">+ View Code<\/a><\/div>\n<\/div>\n<\/div>\n<p>\u7531\u6b64\u53ef\u89c1\uff0cAtomicLong.incrementAndGet\u7684\u5b9e\u73b0\u7528\u4e86\u4e50\u89c2\u9501\u6280\u672f\uff0c\u8c03\u7528\u4e86<a href=\"http:\/\/stackoverflow.com\/questions\/5574241\/interesting-uses-of-sun-misc-unsafe\" target=\"_blank\" rel=\"noopener noreferrer\">sun.misc.Unsafe<\/a>\u7c7b\u5e93\u91cc\u9762\u7684 CAS\u7b97\u6cd5\uff0c\u7528CPU\u6307\u4ee4\u6765\u5b9e\u73b0\u65e0\u9501\u81ea\u589e\u3002\u6240\u4ee5\uff0cAtomicLong.incrementAndGet\u7684\u81ea\u589e\u6bd4\u7528synchronized\u7684\u9501\u6548\u7387\u500d\u589e\u3002<\/p>\n<div>\n<div id=\"highlighter_421543\" class=\"syntaxhighlighter  java\">\n<table border=\"0\" cellspacing=\"0\" cellpadding=\"0\">\n<tbody>\n<tr>\n<td class=\"gutter\">\n<div class=\"line number1 index0 alt2\">1<\/div>\n<div class=\"line number2 index1 alt1\">2<\/div>\n<div class=\"line number3 index2 alt2\">3<\/div>\n<div class=\"line number4 index3 alt1\">4<\/div>\n<div class=\"line number5 index4 alt2\">5<\/div>\n<div class=\"line number6 index5 alt1\">6<\/div>\n<div class=\"line number7 index6 alt2\">7<\/div>\n<div class=\"line number8 index7 alt1\">8<\/div>\n<div class=\"line number9 index8 alt2\">9<\/div>\n<div class=\"line number10 index9 alt1\">10<\/div>\n<div class=\"line number11 index10 alt2\">11<\/div>\n<div class=\"line number12 index11 alt1\">12<\/div>\n<\/td>\n<td class=\"code\">\n<div class=\"container\">\n<div class=\"line number1 index0 alt2\"><code class=\"java keyword\">public<\/code>\u00a0<code class=\"java keyword\">final<\/code>\u00a0<code class=\"java keyword\">int<\/code>\u00a0<code class=\"java plain\">getAndIncrement() {\u00a0 <\/code><\/div>\n<div class=\"line number2 index1 alt1\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java keyword\">for<\/code>\u00a0<code class=\"java plain\">(;;) {\u00a0 <\/code><\/div>\n<div class=\"line number3 index2 alt2\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java keyword\">int<\/code>\u00a0<code class=\"java plain\">current = get();\u00a0 <\/code><\/div>\n<div class=\"line number4 index3 alt1\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java keyword\">int<\/code>\u00a0<code class=\"java plain\">next = current + <\/code><code class=\"java value\">1<\/code><code class=\"java plain\">;\u00a0 <\/code><\/div>\n<div class=\"line number5 index4 alt2\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java keyword\">if<\/code>\u00a0<code class=\"java plain\">(compareAndSet(current, next))\u00a0 <\/code><\/div>\n<div class=\"line number6 index5 alt1\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java keyword\">return<\/code>\u00a0<code class=\"java plain\">current;\u00a0 <\/code><\/div>\n<div class=\"line number7 index6 alt2\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java plain\">}\u00a0 <\/code><\/div>\n<div class=\"line number8 index7 alt1\"><code class=\"java plain\">}\u00a0 <\/code><\/div>\n<div class=\"line number9 index8 alt2\"><code class=\"java spaces\">\u00a0\u00a0<\/code><\/div>\n<div class=\"line number10 index9 alt1\"><code class=\"java keyword\">public<\/code>\u00a0<code class=\"java keyword\">final<\/code>\u00a0<code class=\"java keyword\">boolean<\/code>\u00a0<code class=\"java plain\">compareAndSet(<\/code><code class=\"java keyword\">int<\/code>\u00a0<code class=\"java plain\">expect, <\/code><code class=\"java keyword\">int<\/code>\u00a0<code class=\"java plain\">update) {\u00a0 <\/code><\/div>\n<div class=\"line number11 index10 alt2\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java keyword\">return<\/code>\u00a0<code class=\"java plain\">unsafe.compareAndSwapInt(<\/code><code class=\"java keyword\">this<\/code><code class=\"java plain\">, valueOffset, expect, update);\u00a0 <\/code><\/div>\n<div class=\"line number12 index11 alt1\"><code class=\"java plain\">}<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<p>\u4e0b\u9762\u662f\u6d4b\u8bd5\u4ee3\u7801\uff1a\u53ef\u4ee5\u770b\u5230\u7528AtomicLong.incrementAndGet\u7684\u6027\u80fd\u6bd4\u7528synchronized\u9ad8\u51fa\u51e0\u500d\u3002<\/p>\n<p><a href=\"https:\/\/images0.cnblogs.com\/blog\/28306\/201402\/121727088765464.png\"><img loading=\"lazy\" decoding=\"async\" title=\"2014-02-12_14h56_39\" src=\"https:\/\/images0.cnblogs.com\/blog\/28306\/201402\/121727125108810.png\" alt=\"2014-02-12_14h56_39\" width=\"348\" height=\"178\" border=\"0\" \/><\/a><\/p>\n<div>\n<div id=\"highlighter_163224\" class=\"syntaxhighlighter collapsed  java\">\n<div class=\"toolbar\"><a class=\"toolbar_item command_expandSource expandSource\" href=\"https:\/\/www.cnblogs.com\/Mainz\/p\/3546347.html#\">+ View Code<\/a><\/div>\n<\/div>\n<\/div>\n<h4>CAS\u7684\u4f8b\u5b50\uff1a\u975e\u963b\u585e\u5806\u6808<\/h4>\n<p>\u4e0b\u9762\u662f\u6bd4\u975e\u963b\u585e\u81ea\u589e\u7a0d\u5fae\u590d\u6742\u4e00\u70b9\u7684CAS\u7684\u4f8b\u5b50\uff1a\u975e\u963b\u585e\u5806\u6808\/<code>ConcurrentStack<\/code>\u00a0\u3002<code>ConcurrentStack<\/code>\u00a0\u4e2d\u7684\u00a0<code>push()<\/code>\u00a0\u548c\u00a0<code>pop()<\/code>\u00a0\u64cd\u4f5c\u5728\u7ed3\u6784\u4e0a\u4e0e<code>NonblockingCounter<\/code>\u00a0\u4e0a\u76f8\u4f3c\uff0c\u53ea\u662f\u505a\u7684\u5de5\u4f5c\u6709\u4e9b\u5192\u9669\uff0c\u5e0c\u671b\u5728 \u201c\u63d0\u4ea4\u201d \u5de5\u4f5c\u7684\u65f6\u5019\uff0c\u5e95\u5c42\u5047\u8bbe\u6ca1\u6709\u5931\u6548\u3002<code>push()<\/code>\u00a0\u65b9\u6cd5\u89c2\u5bdf\u5f53\u524d\u6700\u9876\u7684\u8282\u70b9\uff0c\u6784\u5efa\u4e00\u4e2a\u65b0\u8282\u70b9\u653e\u5728\u5806\u6808\u4e0a\uff0c\u7136\u540e\uff0c\u5982\u679c\u6700\u9876\u7aef\u7684\u8282\u70b9\u5728\u521d\u59cb\u89c2\u5bdf\u4e4b\u540e\u6ca1\u6709\u53d8\u5316\uff0c\u90a3\u4e48\u5c31\u5b89\u88c5\u65b0\u8282\u70b9\u3002\u5982\u679c CAS \u5931\u8d25\uff0c\u610f\u5473\u7740\u53e6\u4e00\u4e2a\u7ebf\u7a0b\u5df2\u7ecf\u4fee\u6539\u4e86\u5806\u6808\uff0c\u90a3\u4e48\u8fc7\u7a0b\u5c31\u4f1a\u91cd\u65b0\u5f00\u59cb\u3002<\/p>\n<div>\n<div id=\"highlighter_14282\" class=\"syntaxhighlighter  java\">\n<table border=\"0\" cellspacing=\"0\" cellpadding=\"0\">\n<tbody>\n<tr>\n<td class=\"gutter\">\n<div class=\"line number1 index0 alt2\">1<\/div>\n<div class=\"line number2 index1 alt1\">2<\/div>\n<div class=\"line number3 index2 alt2\">3<\/div>\n<div class=\"line number4 index3 alt1\">4<\/div>\n<div class=\"line number5 index4 alt2\">5<\/div>\n<div class=\"line number6 index5 alt1\">6<\/div>\n<div class=\"line number7 index6 alt2\">7<\/div>\n<div class=\"line number8 index7 alt1\">8<\/div>\n<div class=\"line number9 index8 alt2\">9<\/div>\n<div class=\"line number10 index9 alt1\">10<\/div>\n<div class=\"line number11 index10 alt2\">11<\/div>\n<div class=\"line number12 index11 alt1\">12<\/div>\n<div class=\"line number13 index12 alt2\">13<\/div>\n<div class=\"line number14 index13 alt1\">14<\/div>\n<div class=\"line number15 index14 alt2\">15<\/div>\n<div class=\"line number16 index15 alt1\">16<\/div>\n<div class=\"line number17 index16 alt2\">17<\/div>\n<div class=\"line number18 index17 alt1\">18<\/div>\n<div class=\"line number19 index18 alt2\">19<\/div>\n<div class=\"line number20 index19 alt1\">20<\/div>\n<div class=\"line number21 index20 alt2\">21<\/div>\n<div class=\"line number22 index21 alt1\">22<\/div>\n<div class=\"line number23 index22 alt2\">23<\/div>\n<div class=\"line number24 index23 alt1\">24<\/div>\n<div class=\"line number25 index24 alt2\">25<\/div>\n<div class=\"line number26 index25 alt1\">26<\/div>\n<div class=\"line number27 index26 alt2\">27<\/div>\n<\/td>\n<td class=\"code\">\n<div class=\"container\">\n<div class=\"line number1 index0 alt2\"><code class=\"java keyword\">public<\/code>\u00a0<code class=\"java keyword\">class<\/code>\u00a0<code class=\"java plain\">ConcurrentStack&lt;E&gt; {<\/code><\/div>\n<div class=\"line number2 index1 alt1\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java plain\">AtomicReference&lt;Node&lt;E&gt;&gt; head = <\/code><code class=\"java keyword\">new<\/code>\u00a0<code class=\"java plain\">AtomicReference&lt;Node&lt;E&gt;&gt;();<\/code><\/div>\n<div class=\"line number3 index2 alt2\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java keyword\">public<\/code>\u00a0<code class=\"java keyword\">void<\/code>\u00a0<code class=\"java plain\">push(E item) {<\/code><\/div>\n<div class=\"line number4 index3 alt1\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java plain\">Node&lt;E&gt; newHead = <\/code><code class=\"java keyword\">new<\/code>\u00a0<code class=\"java plain\">Node&lt;E&gt;(item);<\/code><\/div>\n<div class=\"line number5 index4 alt2\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java plain\">Node&lt;E&gt; oldHead;<\/code><\/div>\n<div class=\"line number6 index5 alt1\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java keyword\">do<\/code>\u00a0<code class=\"java plain\">{<\/code><\/div>\n<div class=\"line number7 index6 alt2\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java plain\">oldHead = head.get();<\/code><\/div>\n<div class=\"line number8 index7 alt1\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java plain\">newHead.next = oldHead;<\/code><\/div>\n<div class=\"line number9 index8 alt2\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java plain\">} <\/code><code class=\"java keyword\">while<\/code>\u00a0<code class=\"java plain\">(!head.compareAndSet(oldHead, newHead));<\/code><\/div>\n<div class=\"line number10 index9 alt1\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java plain\">}<\/code><\/div>\n<div class=\"line number11 index10 alt2\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java keyword\">public<\/code>\u00a0<code class=\"java plain\">E pop() {<\/code><\/div>\n<div class=\"line number12 index11 alt1\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java plain\">Node&lt;E&gt; oldHead;<\/code><\/div>\n<div class=\"line number13 index12 alt2\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java plain\">Node&lt;E&gt; newHead;<\/code><\/div>\n<div class=\"line number14 index13 alt1\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java keyword\">do<\/code>\u00a0<code class=\"java plain\">{<\/code><\/div>\n<div class=\"line number15 index14 alt2\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java plain\">oldHead = head.get();<\/code><\/div>\n<div class=\"line number16 index15 alt1\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java keyword\">if<\/code>\u00a0<code class=\"java plain\">(oldHead == <\/code><code class=\"java keyword\">null<\/code><code class=\"java plain\">) <\/code><\/div>\n<div class=\"line number17 index16 alt2\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java keyword\">return<\/code>\u00a0<code class=\"java keyword\">null<\/code><code class=\"java plain\">;<\/code><\/div>\n<div class=\"line number18 index17 alt1\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java plain\">newHead = oldHead.next;<\/code><\/div>\n<div class=\"line number19 index18 alt2\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java plain\">} <\/code><code class=\"java keyword\">while<\/code>\u00a0<code class=\"java plain\">(!head.compareAndSet(oldHead,newHead));<\/code><\/div>\n<div class=\"line number20 index19 alt1\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java keyword\">return<\/code>\u00a0<code class=\"java plain\">oldHead.item;<\/code><\/div>\n<div class=\"line number21 index20 alt2\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java plain\">}<\/code><\/div>\n<div class=\"line number22 index21 alt1\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java keyword\">static<\/code>\u00a0<code class=\"java keyword\">class<\/code>\u00a0<code class=\"java plain\">Node&lt;E&gt; {<\/code><\/div>\n<div class=\"line number23 index22 alt2\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java keyword\">final<\/code>\u00a0<code class=\"java plain\">E item;<\/code><\/div>\n<div class=\"line number24 index23 alt1\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java plain\">Node&lt;E&gt; next;<\/code><\/div>\n<div class=\"line number25 index24 alt2\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java keyword\">public<\/code>\u00a0<code class=\"java plain\">Node(E item) { <\/code><code class=\"java keyword\">this<\/code><code class=\"java plain\">.item = item; }<\/code><\/div>\n<div class=\"line number26 index25 alt1\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java plain\">}<\/code><\/div>\n<div class=\"line number27 index26 alt2\"><code class=\"java plain\">}<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<p>\u5728\u8f7b\u5ea6\u5230\u4e2d\u5ea6\u7684\u4e89\u7528\u60c5\u51b5\u4e0b\uff0c\u975e\u963b\u585e\u7b97\u6cd5\u7684\u6027\u80fd\u4f1a\u8d85\u8d8a\u963b\u585e\u7b97\u6cd5\uff0c\u56e0\u4e3a CAS \u7684\u591a\u6570\u65f6\u95f4\u90fd\u5728\u7b2c\u4e00\u6b21\u5c1d\u8bd5\u65f6\u5c31\u6210\u529f\uff0c\u800c\u53d1\u751f\u4e89\u7528\u65f6\u7684\u5f00\u9500\u4e5f\u4e0d\u6d89\u53ca\u7ebf\u7a0b\u6302\u8d77\u548c\u4e0a\u4e0b\u6587\u5207\u6362\uff0c\u53ea\u591a\u4e86\u51e0\u4e2a\u5faa\u73af\u8fed\u4ee3\u3002\u6ca1\u6709\u4e89\u7528\u7684 CAS \u8981\u6bd4\u6ca1\u6709\u4e89\u7528\u7684\u9501\u4fbf\u5b9c\u5f97\u591a\uff08\u8fd9\u53e5\u8bdd\u80af\u5b9a\u662f\u771f\u7684\uff0c\u56e0\u4e3a\u6ca1\u6709\u4e89\u7528\u7684\u9501\u6d89\u53ca CAS \u52a0\u4e0a\u989d\u5916\u7684\u5904\u7406\uff09\uff0c\u800c\u4e89\u7528\u7684 CAS \u6bd4\u4e89\u7528\u7684\u9501\u83b7\u53d6\u6d89\u53ca\u66f4\u77ed\u7684\u5ef6\u8fdf\u3002<\/p>\n<p>\u5728\u9ad8\u5ea6\u4e89\u7528\u7684\u60c5\u51b5\u4e0b\uff08\u5373\u6709\u591a\u4e2a\u7ebf\u7a0b\u4e0d\u65ad\u4e89\u7528\u4e00\u4e2a\u5185\u5b58\u4f4d\u7f6e\u7684\u65f6\u5019\uff09\uff0c\u57fa\u4e8e\u9501\u7684\u7b97\u6cd5\u5f00\u59cb\u63d0\u4f9b\u6bd4\u975e\u963b\u585e\u7b97\u6cd5\u66f4\u597d\u7684\u541e\u5410\u7387\uff0c\u56e0\u4e3a\u5f53\u7ebf\u7a0b\u963b\u585e\u65f6\uff0c\u5b83\u5c31\u4f1a\u505c\u6b62\u4e89\u7528\uff0c\u8010\u5fc3\u5730\u7b49\u5019\u8f6e\u5230\u81ea\u5df1\uff0c\u4ece\u800c\u907f\u514d\u4e86\u8fdb\u4e00\u6b65\u4e89\u7528\u3002\u4f46\u662f\uff0c\u8fd9\u4e48\u9ad8\u7684\u4e89\u7528\u7a0b\u5ea6\u5e76\u4e0d\u5e38\u89c1\uff0c\u56e0\u4e3a\u591a\u6570\u65f6\u5019\uff0c\u7ebf\u7a0b\u4f1a\u628a\u7ebf\u7a0b\u672c\u5730\u7684\u8ba1\u7b97\u4e0e\u4e89\u7528\u5171\u4eab\u6570\u636e\u7684\u64cd\u4f5c\u5206\u5f00\uff0c\u4ece\u800c\u7ed9\u5176\u4ed6\u7ebf\u7a0b\u4f7f\u7528\u5171\u4eab\u6570\u636e\u7684\u673a\u4f1a\u3002<\/p>\n<h4>CAS\u7684\u4f8b\u5b503\uff1a\u975e\u963b\u585e\u94fe\u8868<\/h4>\n<p>\u4ee5\u4e0a\u7684\u793a\u4f8b\uff08\u81ea\u589e\u8ba1\u6570\u5668\u548c\u5806\u6808\uff09\u90fd\u662f\u975e\u5e38\u7b80\u5355\u7684\u975e\u963b\u585e\u7b97\u6cd5\uff0c\u4e00\u65e6\u638c\u63e1\u4e86\u5728\u5faa\u73af\u4e2d\u4f7f\u7528 CAS\uff0c\u5c31\u53ef\u4ee5\u5bb9\u6613\u5730\u6a21\u4eff\u5b83\u4eec\u3002\u5bf9\u4e8e\u66f4\u590d\u6742\u7684\u6570\u636e\u7ed3\u6784\uff0c\u975e\u963b\u585e\u7b97\u6cd5\u8981\u6bd4\u8fd9\u4e9b\u7b80\u5355\u793a\u4f8b\u590d\u6742\u5f97\u591a\uff0c\u56e0\u4e3a\u4fee\u6539\u94fe\u8868\u3001\u6811\u6216\u54c8\u5e0c\u8868\u53ef\u80fd\u6d89\u53ca\u5bf9\u591a\u4e2a\u6307\u9488\u7684\u66f4\u65b0\u3002CAS \u652f\u6301\u5bf9\u5355\u4e00\u6307\u9488\u7684\u539f\u5b50\u6027\u6761\u4ef6\u66f4\u65b0\uff0c\u4f46\u662f\u4e0d\u652f\u6301\u4e24\u4e2a\u4ee5\u4e0a\u7684\u6307\u9488\u3002\u6240\u4ee5\uff0c\u8981\u6784\u5efa\u4e00\u4e2a\u975e\u963b\u585e\u7684\u94fe\u8868\u3001\u6811\u6216\u54c8\u5e0c\u8868\uff0c\u9700\u8981\u627e\u5230\u4e00\u79cd\u65b9\u5f0f\uff0c\u53ef\u4ee5\u7528 CAS \u66f4\u65b0\u591a\u4e2a\u6307\u9488\uff0c\u540c\u65f6\u4e0d\u4f1a\u8ba9\u6570\u636e\u7ed3\u6784\u5904\u4e8e\u4e0d\u4e00\u81f4\u7684\u72b6\u6001\u3002<\/p>\n<p>\u5728\u94fe\u8868\u7684\u5c3e\u90e8\u63d2\u5165\u5143\u7d20\uff0c\u901a\u5e38\u6d89\u53ca\u5bf9\u4e24\u4e2a\u6307\u9488\u7684\u66f4\u65b0\uff1a\u201c\u5c3e\u201d \u6307\u9488\u603b\u662f\u6307\u5411\u5217\u8868\u4e2d\u7684\u6700\u540e\u4e00\u4e2a\u5143\u7d20\uff0c\u201c\u4e0b\u4e00\u4e2a\u201d \u6307\u9488\u4ece\u8fc7\u53bb\u7684\u6700\u540e\u4e00\u4e2a\u5143\u7d20\u6307\u5411\u65b0\u63d2\u5165\u7684\u5143\u7d20\u3002\u56e0\u4e3a\u9700\u8981\u66f4\u65b0\u4e24\u4e2a\u6307\u9488\uff0c\u6240\u4ee5\u9700\u8981\u4e24\u4e2a CAS\u3002\u5728\u72ec\u7acb\u7684 CAS \u4e2d\u66f4\u65b0\u4e24\u4e2a\u6307\u9488\u5e26\u6765\u4e86\u4e24\u4e2a\u9700\u8981\u8003\u8651\u7684\u6f5c\u5728\u95ee\u9898\uff1a\u5982\u679c\u7b2c\u4e00\u4e2a CAS \u6210\u529f\uff0c\u800c\u7b2c\u4e8c\u4e2a CAS \u5931\u8d25\uff0c\u4f1a\u53d1\u751f\u4ec0\u4e48\uff1f\u5982\u679c\u5176\u4ed6\u7ebf\u7a0b\u5728\u7b2c\u4e00\u4e2a\u548c\u7b2c\u4e8c\u4e2a CAS \u4e4b\u95f4\u4f01\u56fe\u8bbf\u95ee\u94fe\u8868\uff0c\u4f1a\u53d1\u751f\u4ec0\u4e48\uff1f<\/p>\n<p>\u5bf9\u4e8e\u975e\u590d\u6742\u6570\u636e\u7ed3\u6784\uff0c\u6784\u5efa\u975e\u963b\u585e\u7b97\u6cd5\u7684 \u201c\u6280\u5de7\u201d \u662f\u786e\u4fdd\u6570\u636e\u7ed3\u6784\u603b\u5904\u4e8e\u4e00\u81f4\u7684\u72b6\u6001\uff08\u751a\u81f3\u5305\u62ec\u5728\u7ebf\u7a0b\u5f00\u59cb\u4fee\u6539\u6570\u636e\u7ed3\u6784\u548c\u5b83\u5b8c\u6210\u4fee\u6539\u4e4b\u95f4\uff09\uff0c\u8fd8\u8981\u786e\u4fdd\u5176\u4ed6\u7ebf\u7a0b\u4e0d\u4ec5\u80fd\u591f\u5224\u65ad\u51fa\u7b2c\u4e00\u4e2a\u7ebf\u7a0b\u5df2\u7ecf\u5b8c\u6210\u4e86\u66f4\u65b0\u8fd8\u662f\u5904\u5728\u66f4\u65b0\u7684\u4e2d\u9014\uff0c\u8fd8\u80fd\u591f\u5224\u65ad\u51fa\u5982\u679c\u7b2c\u4e00\u4e2a\u7ebf\u7a0b\u8d70\u5411 AWOL\uff0c\u5b8c\u6210\u66f4\u65b0\u8fd8\u9700\u8981\u4ec0\u4e48\u64cd\u4f5c\u3002\u5982\u679c\u7ebf\u7a0b\u53d1\u73b0\u4e86\u5904\u5728\u66f4\u65b0\u4e2d\u9014\u7684\u6570\u636e\u7ed3\u6784\uff0c\u5b83\u5c31\u53ef\u4ee5 \u201c\u5e2e\u52a9\u201d \u6b63\u5728\u6267\u884c\u66f4\u65b0\u7684\u7ebf\u7a0b\u5b8c\u6210\u66f4\u65b0\uff0c\u7136\u540e\u518d\u8fdb\u884c\u81ea\u5df1\u7684\u64cd\u4f5c\u3002\u5f53\u7b2c\u4e00\u4e2a\u7ebf\u7a0b\u56de\u6765\u8bd5\u56fe\u5b8c\u6210\u81ea\u5df1\u7684\u66f4\u65b0\u65f6\uff0c\u4f1a\u53d1\u73b0\u4e0d\u518d\u9700\u8981\u4e86\uff0c\u8fd4\u56de\u5373\u53ef\uff0c\u56e0\u4e3a CAS \u4f1a\u68c0\u6d4b\u5230\u5e2e\u52a9\u7ebf\u7a0b\u7684\u5e72\u9884\uff08\u5728\u8fd9\u79cd\u60c5\u51b5\u4e0b\uff0c\u662f\u5efa\u8bbe\u6027\u7684\u5e72\u9884\uff09\u3002<\/p>\n<p>\u8fd9\u79cd \u201c\u5e2e\u52a9\u90bb\u5c45\u201d \u7684\u8981\u6c42\uff0c\u5bf9\u4e8e\u8ba9\u6570\u636e\u7ed3\u6784\u514d\u53d7\u5355\u4e2a\u7ebf\u7a0b\u5931\u8d25\u7684\u5f71\u54cd\uff0c\u662f\u5fc5\u9700\u7684\u3002\u5982\u679c\u7ebf\u7a0b\u53d1\u73b0\u6570\u636e\u7ed3\u6784\u6b63\u5904\u5728\u88ab\u5176\u4ed6\u7ebf\u7a0b\u66f4\u65b0\u7684\u4e2d\u9014\uff0c\u7136\u540e\u5c31\u7b49\u5019\u5176\u4ed6\u7ebf\u7a0b\u5b8c\u6210\u66f4\u65b0\uff0c\u90a3\u4e48\u5982\u679c\u5176\u4ed6\u7ebf\u7a0b\u5728\u64cd\u4f5c\u4e2d\u9014\u5931\u8d25\uff0c\u8fd9\u4e2a\u7ebf\u7a0b\u5c31\u53ef\u80fd\u6c38\u8fdc\u7b49\u5019\u4e0b\u53bb\u3002\u5373\u4f7f\u4e0d\u51fa\u73b0\u6545\u969c\uff0c\u8fd9\u79cd\u65b9\u5f0f\u4e5f\u4f1a\u63d0\u4f9b\u7cdf\u7cd5\u7684\u6027\u80fd\uff0c\u56e0\u4e3a\u65b0\u5230\u8fbe\u7684\u7ebf\u7a0b\u5fc5\u987b\u653e\u5f03\u5904\u7406\u5668\uff0c\u5bfc\u81f4\u4e0a\u4e0b\u6587\u5207\u6362\uff0c\u6216\u8005\u7b49\u5230\u81ea\u5df1\u7684\u65f6\u95f4\u7247\u8fc7\u671f\uff08\u800c\u8fd9\u66f4\u7cdf\uff09\u3002<\/p>\n<div>\n<div id=\"highlighter_780784\" class=\"syntaxhighlighter  java\">\n<table border=\"0\" cellspacing=\"0\" cellpadding=\"0\">\n<tbody>\n<tr>\n<td class=\"gutter\">\n<div class=\"line number1 index0 alt2\">1<\/div>\n<div class=\"line number2 index1 alt1\">2<\/div>\n<div class=\"line number3 index2 alt2\">3<\/div>\n<div class=\"line number4 index3 alt1\">4<\/div>\n<div class=\"line number5 index4 alt2\">5<\/div>\n<div class=\"line number6 index5 alt1\">6<\/div>\n<div class=\"line number7 index6 alt2\">7<\/div>\n<div class=\"line number8 index7 alt1\">8<\/div>\n<div class=\"line number9 index8 alt2\">9<\/div>\n<div class=\"line number10 index9 alt1\">10<\/div>\n<div class=\"line number11 index10 alt2\">11<\/div>\n<div class=\"line number12 index11 alt1\">12<\/div>\n<div class=\"line number13 index12 alt2\">13<\/div>\n<div class=\"line number14 index13 alt1\">14<\/div>\n<div class=\"line number15 index14 alt2\">15<\/div>\n<div class=\"line number16 index15 alt1\">16<\/div>\n<div class=\"line number17 index16 alt2\">17<\/div>\n<div class=\"line number18 index17 alt1\">18<\/div>\n<div class=\"line number19 index18 alt2\">19<\/div>\n<div class=\"line number20 index19 alt1\">20<\/div>\n<div class=\"line number21 index20 alt2\">21<\/div>\n<div class=\"line number22 index21 alt1\">22<\/div>\n<div class=\"line number23 index22 alt2\">23<\/div>\n<div class=\"line number24 index23 alt1\">24<\/div>\n<div class=\"line number25 index24 alt2\">25<\/div>\n<div class=\"line number26 index25 alt1\">26<\/div>\n<div class=\"line number27 index26 alt2\">27<\/div>\n<div class=\"line number28 index27 alt1\">28<\/div>\n<div class=\"line number29 index28 alt2\">29<\/div>\n<div class=\"line number30 index29 alt1\">30<\/div>\n<\/td>\n<td class=\"code\">\n<div class=\"container\">\n<div class=\"line number1 index0 alt2\"><code class=\"java keyword\">public<\/code>\u00a0<code class=\"java keyword\">class<\/code>\u00a0<code class=\"java plain\">LinkedQueue &lt;E&gt; {<\/code><\/div>\n<div class=\"line number2 index1 alt1\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java keyword\">private<\/code>\u00a0<code class=\"java keyword\">static<\/code>\u00a0<code class=\"java keyword\">class<\/code>\u00a0<code class=\"java plain\">Node &lt;E&gt; {<\/code><\/div>\n<div class=\"line number3 index2 alt2\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java keyword\">final<\/code>\u00a0<code class=\"java plain\">E item;<\/code><\/div>\n<div class=\"line number4 index3 alt1\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java keyword\">final<\/code>\u00a0<code class=\"java plain\">AtomicReference&lt;Node&lt;E&gt;&gt; next;<\/code><\/div>\n<div class=\"line number5 index4 alt2\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java plain\">Node(E item, Node&lt;E&gt; next) {<\/code><\/div>\n<div class=\"line number6 index5 alt1\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java keyword\">this<\/code><code class=\"java plain\">.item = item;<\/code><\/div>\n<div class=\"line number7 index6 alt2\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java keyword\">this<\/code><code class=\"java plain\">.next = <\/code><code class=\"java keyword\">new<\/code>\u00a0<code class=\"java plain\">AtomicReference&lt;Node&lt;E&gt;&gt;(next);<\/code><\/div>\n<div class=\"line number8 index7 alt1\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java plain\">}<\/code><\/div>\n<div class=\"line number9 index8 alt2\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java plain\">}<\/code><\/div>\n<div class=\"line number10 index9 alt1\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java keyword\">private<\/code>\u00a0<code class=\"java plain\">AtomicReference&lt;Node&lt;E&gt;&gt; head<\/code><\/div>\n<div class=\"line number11 index10 alt2\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java plain\">= <\/code><code class=\"java keyword\">new<\/code>\u00a0<code class=\"java plain\">AtomicReference&lt;Node&lt;E&gt;&gt;(<\/code><code class=\"java keyword\">new<\/code>\u00a0<code class=\"java plain\">Node&lt;E&gt;(<\/code><code class=\"java keyword\">null<\/code><code class=\"java plain\">, <\/code><code class=\"java keyword\">null<\/code><code class=\"java plain\">));<\/code><\/div>\n<div class=\"line number12 index11 alt1\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java keyword\">private<\/code>\u00a0<code class=\"java plain\">AtomicReference&lt;Node&lt;E&gt;&gt; tail = head;<\/code><\/div>\n<div class=\"line number13 index12 alt2\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java keyword\">public<\/code>\u00a0<code class=\"java keyword\">boolean<\/code>\u00a0<code class=\"java plain\">put(E item) {<\/code><\/div>\n<div class=\"line number14 index13 alt1\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java plain\">Node&lt;E&gt; newNode = <\/code><code class=\"java keyword\">new<\/code>\u00a0<code class=\"java plain\">Node&lt;E&gt;(item, <\/code><code class=\"java keyword\">null<\/code><code class=\"java plain\">);<\/code><\/div>\n<div class=\"line number15 index14 alt2\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java keyword\">while<\/code>\u00a0<code class=\"java plain\">(<\/code><code class=\"java keyword\">true<\/code><code class=\"java plain\">) {<\/code><\/div>\n<div class=\"line number16 index15 alt1\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java plain\">Node&lt;E&gt; curTail = tail.get();<\/code><\/div>\n<div class=\"line number17 index16 alt2\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java plain\">Node&lt;E&gt; residue = curTail.next.get();<\/code><\/div>\n<div class=\"line number18 index17 alt1\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java keyword\">if<\/code>\u00a0<code class=\"java plain\">(curTail == tail.get()) {<\/code><\/div>\n<div class=\"line number19 index18 alt2\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java keyword\">if<\/code>\u00a0<code class=\"java plain\">(residue == <\/code><code class=\"java keyword\">null<\/code><code class=\"java plain\">) <\/code><code class=\"java comments\">\/* A *\/<\/code>\u00a0<code class=\"java plain\">{<\/code><\/div>\n<div class=\"line number20 index19 alt1\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java keyword\">if<\/code>\u00a0<code class=\"java plain\">(curTail.next.compareAndSet(<\/code><code class=\"java keyword\">null<\/code><code class=\"java plain\">, newNode)) <\/code><code class=\"java comments\">\/* C *\/<\/code>\u00a0<code class=\"java plain\">{<\/code><\/div>\n<div class=\"line number21 index20 alt2\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java plain\">tail.compareAndSet(curTail, newNode) <\/code><code class=\"java comments\">\/* D *\/<\/code>\u00a0<code class=\"java plain\">;<\/code><\/div>\n<div class=\"line number22 index21 alt1\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java keyword\">return<\/code>\u00a0<code class=\"java keyword\">true<\/code><code class=\"java plain\">;<\/code><\/div>\n<div class=\"line number23 index22 alt2\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java plain\">}<\/code><\/div>\n<div class=\"line number24 index23 alt1\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java plain\">} <\/code><code class=\"java keyword\">else<\/code>\u00a0<code class=\"java plain\">{<\/code><\/div>\n<div class=\"line number25 index24 alt2\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java plain\">tail.compareAndSet(curTail, residue) <\/code><code class=\"java comments\">\/* B *\/<\/code><code class=\"java plain\">;<\/code><\/div>\n<div class=\"line number26 index25 alt1\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java plain\">}<\/code><\/div>\n<div class=\"line number27 index26 alt2\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java plain\">}<\/code><\/div>\n<div class=\"line number28 index27 alt1\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java plain\">}<\/code><\/div>\n<div class=\"line number29 index28 alt2\"><code class=\"java spaces\">\u00a0\u00a0\u00a0\u00a0<\/code><code class=\"java plain\">}<\/code><\/div>\n<div class=\"line number30 index29 alt1\"><code class=\"java plain\">}<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<p>\u5177\u4f53\u7b97\u6cd5\u76f8\u89c1<a href=\"http:\/\/www.ibm.com\/developerworks\/cn\/java\/j-jtp04186\/\" target=\"_blank\" rel=\"noopener noreferrer\">IBM Developerworks<\/a><\/p>\n<h4>Java\u7684ConcurrentHashMap\u7684\u5b9e\u73b0\u539f\u7406<\/h4>\n<p>Java5\u4e2d\u7684ConcurrentHashMap\uff0c\u7ebf\u7a0b\u5b89\u5168\uff0c\u8bbe\u8ba1\u5de7\u5999\uff0c\u7528\u6876\u7c92\u5ea6\u7684\u9501\uff0c\u907f\u514d\u4e86put\u548cget\u4e2d\u5bf9\u6574\u4e2amap\u7684\u9501\u5b9a\uff0c\u5c24\u5176\u5728get\u4e2d\uff0c\u53ea\u5bf9\u4e00\u4e2aHashEntry\u505a\u9501\u5b9a\u64cd\u4f5c\uff0c\u6027\u80fd\u63d0\u5347\u662f\u663e\u800c\u6613\u89c1\u7684\u3002<\/p>\n<p><a href=\"https:\/\/images0.cnblogs.com\/blog\/28306\/201402\/121727157448397.png\"><img loading=\"lazy\" decoding=\"async\" title=\"8aea11a8-4184-3f1f-aba7-169aa5e0797a\" src=\"https:\/\/images0.cnblogs.com\/blog\/28306\/201402\/121727197879329.png\" alt=\"8aea11a8-4184-3f1f-aba7-169aa5e0797a\" width=\"502\" height=\"360\" border=\"0\" \/><\/a><\/p>\n<p>\u5177\u4f53\u5b9e\u73b0\u4e2d\u4f7f\u7528\u4e86\u9501\u5206\u79bb\u673a\u5236\uff0c\u5728<a href=\"http:\/\/www.iteye.com\/topic\/344876\" target=\"_blank\" rel=\"noopener noreferrer\">\u8fd9\u4e2a\u5e16\u5b50<\/a>\u4e2d\u6709\u975e\u5e38\u8be6\u7ec6\u7684\u8ba8\u8bba\u3002<a href=\"https:\/\/www.ibm.com\/developerworks\/java\/library\/j-jtp08223\/\" target=\"_blank\" rel=\"noopener noreferrer\">\u8fd9\u91cc<\/a>\u6709\u5173\u4e8eJava\u5185\u5b58\u6a21\u578b\u7ed3\u5408ConcurrentHashMap\u7684\u5206\u6790\u3002\u4ee5\u4e0b\u662fJDK6\u7684ConcurrentHashMap\u7684\u6e90\u7801\uff1a<\/p>\n<div>\n<div id=\"highlighter_840573\" class=\"syntaxhighlighter collapsed  java\">\n<div class=\"toolbar\"><a class=\"toolbar_item command_expandSource expandSource\" href=\"https:\/\/www.cnblogs.com\/Mainz\/p\/3546347.html#\">+ View Code<\/a><\/div>\n<\/div>\n<\/div>\n<h4>Java\u7684ConcurrentLinkedQueue\u5b9e\u73b0\u65b9\u6cd5<\/h4>\n<p><a href=\"http:\/\/docs.oracle.com\/javase\/1.5.0\/docs\/api\/java\/util\/concurrent\/ConcurrentLinkedQueue.html\" target=\"_blank\" rel=\"noopener noreferrer\">ConcurrentLinkedQueue<\/a>\u4e5f\u662f\u540c\u6837\u4f7f\u7528\u4e86CAS\u6307\u4ee4\uff0c\u4f46\u5176\u6027\u80fd\u5e76\u4e0d\u9ad8\u56e0\u4e3a<a href=\"http:\/\/www.infoq.com\/articles\/scalable-java-components\/\" target=\"_blank\" rel=\"noopener noreferrer\">\u592a\u591aCAS<\/a>\u64cd\u4f5c\u3002\u5176\u6e90\u7801\u5982\u4e0b\uff1a<\/p>\n<div>\n<div id=\"highlighter_926958\" class=\"syntaxhighlighter collapsed  java\">\n<div class=\"toolbar\"><a class=\"toolbar_item command_expandSource expandSource\" href=\"https:\/\/www.cnblogs.com\/Mainz\/p\/3546347.html#\">+ View Code<\/a><\/div>\n<\/div>\n<\/div>\n<h4>\u9ad8\u5e76\u53d1\u73af\u5883\u4e0b\u4f18\u5316\u9501\u6216\u65e0\u9501\uff08lock-free\uff09\u7684\u8bbe\u8ba1\u601d\u8def<\/h4>\n<p>\u670d\u52a1\u7aef\u7f16\u7a0b\u76843\u5927\u6027\u80fd\u6740\u624b\uff1a1\u3001\u5927\u91cf\u7ebf\u7a0b\u5bfc\u81f4\u7684\u7ebf\u7a0b\u5207\u6362\u5f00\u9500\u30022\u3001\u9501\u30023\u3001\u975e\u5fc5\u8981\u7684\u5185\u5b58\u62f7\u8d1d\u3002\u5728\u9ad8\u5e76\u53d1\u4e0b,\u5bf9\u4e8e\u7eaf\u5185\u5b58\u64cd\u4f5c\u6765\u8bf4,\u5355\u7ebf\u7a0b\u662f\u8981\u6bd4\u591a\u7ebf\u7a0b\u5feb\u7684, \u53ef\u4ee5\u6bd4\u8f83\u4e00\u4e0b\u591a\u7ebf\u7a0b\u7a0b\u5e8f\u5728\u538b\u529b\u6d4b\u8bd5\u4e0bcpu\u7684sy\u548cni\u767e\u5206\u6bd4\u3002\u9ad8\u5e76\u53d1\u73af\u5883\u4e0b\u8981\u5b9e\u73b0\u9ad8\u541e\u5410\u91cf\u548c\u7ebf\u7a0b\u5b89\u5168\uff0c\u4e24\u4e2a\u601d\u8def\uff1a\u4e00\u4e2a\u662f\u7528\u4f18\u5316\u7684\u9501\u5b9e\u73b0\uff0c\u4e00\u4e2a\u662flock-free\u7684\u65e0\u9501\u7ed3\u6784\u3002\u4f46\u975e\u963b\u585e\u7b97\u6cd5\u8981\u6bd4\u57fa\u4e8e\u9501\u7684\u7b97\u6cd5\u590d\u6742\u5f97\u591a\u3002\u5f00\u53d1\u975e\u963b\u585e\u7b97\u6cd5\u662f\u76f8\u5f53\u4e13\u4e1a\u7684\u8bad\u7ec3\uff0c\u800c\u4e14\u8981\u8bc1\u660e\u7b97\u6cd5\u7684\u6b63\u786e\u4e5f\u6781\u4e3a\u56f0\u96be\uff0c\u4e0d\u4ec5\u548c\u5177\u4f53\u7684\u76ee\u6807\u673a\u5668\u5e73\u53f0\u548c\u7f16\u8bd1\u5668\u76f8\u5173\uff0c\u800c\u4e14\u9700\u8981\u590d\u6742\u7684\u6280\u5de7\u548c\u4e25\u683c\u7684\u6d4b\u8bd5\u3002\u867d\u7136Lock-Free\u7f16\u7a0b\u975e\u5e38\u56f0\u96be\uff0c\u4f46\u662f\u5b83\u901a\u5e38\u53ef\u4ee5\u5e26\u6765\u6bd4\u57fa\u4e8e\u9501\u7f16\u7a0b\u66f4\u9ad8\u7684\u541e\u5410\u91cf\u3002\u6240\u4ee5Lock-Free\u7f16\u7a0b\u662f\u5927\u6709\u524d\u9014\u7684\u6280\u672f\u3002\u5b83\u5728\u7ebf\u7a0b\u4e2d\u6b62\u3001\u4f18\u5148\u7ea7\u5012\u7f6e\u4ee5\u53ca\u4fe1\u53f7\u5b89\u5168\u7b49\u65b9\u9762\u90fd\u6709\u7740\u826f\u597d\u7684\u8868\u73b0\u3002<\/p>\n<ul>\n<li><strong>\u4f18\u5316\u9501\u5b9e\u73b0\u7684\u4f8b\u5b50<\/strong>\uff1aJava\u4e2d\u7684<a href=\"http:\/\/www.docjar.com\/html\/api\/java\/util\/concurrent\/ConcurrentHashMap.java.html\" target=\"_blank\" rel=\"noopener noreferrer\">ConcurrentHashMap<\/a>\uff0c\u8bbe\u8ba1\u5de7\u5999\uff0c\u7528\u6876\u7c92\u5ea6\u7684\u9501\u548c\u9501\u5206\u79bb\u673a\u5236\uff0c\u907f\u514d\u4e86put\u548cget\u4e2d\u5bf9\u6574\u4e2amap\u7684\u9501\u5b9a\uff0c\u5c24\u5176\u5728get\u4e2d\uff0c\u53ea\u5bf9\u4e00\u4e2aHashEntry\u505a\u9501\u5b9a\u64cd\u4f5c\uff0c\u6027\u80fd\u63d0\u5347\u662f\u663e\u800c\u6613\u89c1\u7684\uff08\u8be6\u7ec6\u5206\u6790\u89c1\u300a<a href=\"http:\/\/www.ibm.com\/developerworks\/cn\/java\/java-lo-concurrenthashmap\/\" target=\"_blank\" rel=\"noopener noreferrer\">\u63a2\u7d22 ConcurrentHashMap \u9ad8\u5e76\u53d1\u6027\u7684\u5b9e\u73b0\u673a\u5236<\/a>\u300b\uff09\u3002<\/li>\n<li><strong>Lock-free\u65e0\u9501\u7684\u4f8b\u5b50<\/strong>\uff1aCAS\uff08CPU\u7684Compare-And-Swap\u6307\u4ee4\uff09\u7684\u5229\u7528\u548cLMAX\u7684<a href=\"http:\/\/lmax-exchange.github.io\/disruptor\/\" target=\"_blank\" rel=\"noopener noreferrer\">disruptor<\/a>\u65e0\u9501\u6d88\u606f\u961f\u5217\u6570\u636e\u7ed3\u6784\u7b49\u3002\u6709\u5174\u8da3\u4e86\u89e3LMAX\u7684<a href=\"http:\/\/lmax-exchange.github.io\/disruptor\/\" target=\"_blank\" rel=\"noopener noreferrer\">disruptor<\/a>\u65e0\u9501\u6d88\u606f\u961f\u5217\u6570\u636e\u7ed3\u6784\u7684\u53ef\u4ee5\u79fb\u6b65<a href=\"http:\/\/www.slideshare.net\/guynir\/the-edge-2012-disruptor-guy-raz-nir-published\" target=\"_blank\" rel=\"noopener noreferrer\">slideshare<\/a>\u3002<\/li>\n<\/ul>\n<p><a href=\"http:\/\/lmax-exchange.github.io\/disruptor\/\" target=\"_blank\" rel=\"noopener noreferrer\">disruptor<\/a>\u65e0\u9501\u6d88\u606f\u961f\u5217\u6570\u636e\u7ed3\u6784\u7684\u7c7b\u56fe\u548c<a href=\"http:\/\/disruptor.googlecode.com\/files\/Disruptor-1.0.pdf\" target=\"_blank\" rel=\"noopener noreferrer\">\u6280\u672f\u6587\u6863\u4e0b\u8f7d<\/a><\/p>\n<p><a href=\"https:\/\/images0.cnblogs.com\/blog\/28306\/201402\/121727220603460.png\"><img loading=\"lazy\" decoding=\"async\" title=\"2014-02-12_16h55_36\" src=\"https:\/\/images0.cnblogs.com\/blog\/28306\/201402\/121727239741075.png\" alt=\"2014-02-12_16h55_36\" width=\"640\" height=\"463\" border=\"0\" \/><\/a><\/p>\n<p>\u53e6\u5916\uff0c\u5728\u8bbe\u8ba1\u601d\u8def\u4e0a\u9664\u4e86\u5c3d\u91cf\u51cf\u5c11\u8d44\u6e90\u4e89\u7528\u4ee5\u5916\uff0c\u8fd8\u53ef\u4ee5\u501f\u9274<a href=\"http:\/\/javasogo.iteye.com\/blog\/1060114\" target=\"_blank\" rel=\"noopener noreferrer\">nginx\/node.js<\/a>\u7b49\u5355\u7ebf\u7a0b\u5927\u5faa\u73af\u7684\u673a\u5236\uff0c\u7528\u5355\u7ebf\u7a0b\u6216CPU\u6570\u76f8\u540c\u7684\u7ebf\u7a0b\u5f00\u8f9f\u5927\u7684\u961f\u5217\uff0c\u5e76\u53d1\u7684\u65f6\u5019\u4efb\u52a1\u538b\u5165\u961f\u5217\uff0c\u7ebf\u7a0b\u8f6e\u8be2\u7136\u540e\u4e00\u4e2a\u4e2a\u987a\u5e8f\u6267\u884c\u3002\u7531\u4e8e\u6bcf\u4e2a\u90fd\u91c7\u7528\u5f02\u6b65I\/O\uff0c\u6ca1\u6709\u963b\u585e\u7ebf\u7a0b\u3002\u8fd9\u4e2a\u5927\u961f\u5217\u53ef\u4ee5\u4f7f\u7528RabbitMQueue\uff0c\u6216\u662fJDK\u7684\u540c\u6b65\u961f\u5217\uff08\u6027\u80fd\u7a0d\u5dee\uff09\uff0c\u6216\u662f\u4f7f\u7528<a href=\"http:\/\/lmax-exchange.github.io\/disruptor\/\" target=\"_blank\" rel=\"noopener noreferrer\">Disruptor\u65e0\u9501\u961f\u5217<\/a>(Java)\u3002\u4efb\u52a1\u5904\u7406\u53ef\u4ee5\u5168\u90e8\u653e\u5728\u5185\u5b58\uff08\u591a\u7ea7\u7f13\u5b58\u3001\u8bfb\u5199\u5206\u79bb\u3001ConcurrentHashMap\u3001\u751a\u81f3\u5206\u5e03\u5f0f\u7f13\u5b58Redis\uff09\u4e2d\u8fdb\u884c\u589e\u5220\u6539\u67e5\u3002\u6700\u540e\u7528Quarz\u7ef4\u62a4\u5b9a\u65f6\u628a\u7f13\u5b58\u6570\u636e\u540c\u6b65\u5230DB\u4e2d\u3002\u5f53\u7136\uff0c\u8fd9\u53ea\u662f\u4e2d\u5c0f\u578b\u7cfb\u7edf\u7684\u601d\u8def\uff0c\u5982\u679c\u662f\u5927\u578b\u5206\u5e03\u5f0f\u7cfb\u7edf\u4f1a\u975e\u5e38\u590d\u6742\uff0c\u9700\u8981\u5206\u800c\u6cbb\u7406\uff0c\u7528SOA\u7684\u601d\u8def\uff0c\u53c2\u8003<a href=\"http:\/\/www.iteye.com\/topic\/1128561\" target=\"_blank\" rel=\"noopener noreferrer\">\u8fd9\u7bc7\u6587\u7ae0\u7684\u56fe<\/a>\u3002\uff08\u6ce8\uff1aRedis\u662f\u5355\u7ebf\u7a0b\u7684\u7eaf\u5185\u5b58\u6570\u636e\u5e93\uff0c\u5355\u7ebf\u7a0b\u65e0\u9700\u9501\uff0c\u800cMemcache\u662f\u591a\u7ebf\u7a0b\u7684\u5e26CAS\u7b97\u6cd5\uff0c\u4e24\u8005\u90fd\u4f7f\u7528epoll\uff0cno-blocking io\uff09<\/p>\n<p><a href=\"https:\/\/images0.cnblogs.com\/blog\/28306\/201402\/121727267405520.png\"><img loading=\"lazy\" decoding=\"async\" title=\"png;base643f17317a5d7e7fe9\" src=\"https:\/\/images0.cnblogs.com\/blog\/28306\/201402\/121727294975265.png\" alt=\"png;base643f17317a5d7e7fe9\" width=\"640\" height=\"479\" border=\"0\" \/><\/a><\/p>\n<h4>\u6df1\u5165JVM\u7684OS\u7684\u65e0\u9501\u975e\u963b\u585e\u7b97\u6cd5<\/h4>\n<p>\u5982\u679c\u6df1\u5165 JVM \u548c\u64cd\u4f5c\u7cfb\u7edf\uff0c\u4f1a\u53d1\u73b0\u975e\u963b\u585e\u7b97\u6cd5\u65e0\u5904\u4e0d\u5728\u3002<strong>\u5783\u573e\u6536\u96c6\u5668<\/strong>\u4f7f\u7528\u975e\u963b\u585e\u7b97\u6cd5\u52a0\u5feb\u5e76\u53d1\u548c\u5e73\u884c\u7684\u5783\u573e\u641c\u96c6\uff1b<strong>\u8c03\u5ea6\u5668<\/strong>\u4f7f\u7528\u975e\u963b\u585e\u7b97\u6cd5\u6709\u6548\u5730\u8c03\u5ea6\u7ebf\u7a0b\u548c\u8fdb\u7a0b\uff0c\u5b9e\u73b0\u5185\u5728\u9501\u3002\u5728 Mustang\uff08Java 6.0\uff09\u4e2d\uff0c\u57fa\u4e8e\u9501\u7684\u00a0<code>SynchronousQueue<\/code>\u00a0\u7b97\u6cd5\u88ab\u65b0\u7684\u975e\u963b\u585e\u7248\u672c\u4ee3\u66ff\u3002\u5f88\u5c11\u6709\u5f00\u53d1\u4eba\u5458\u4f1a\u76f4\u63a5\u4f7f\u7528\u00a0<code>SynchronousQueue<\/code>\uff0c\u4f46\u662f\u901a\u8fc7\u00a0<code>Executors.newCachedThreadPool()<\/code>\u00a0\u5de5\u5382\u6784\u5efa\u7684\u7ebf\u7a0b\u6c60\u7528\u5b83\u4f5c\u4e3a\u5de5\u4f5c\u961f\u5217\u3002\u6bd4\u8f83\u7f13\u5b58\u7ebf\u7a0b\u6c60\u6027\u80fd\u7684\u5bf9\u6bd4\u6d4b\u8bd5\u663e\u793a\uff0c<strong>\u65b0\u7684\u975e\u963b\u585e\u540c\u6b65\u961f\u5217<\/strong>\u5b9e\u73b0\u63d0\u4f9b\u4e86\u51e0\u4e4e\u662f\u5f53\u524d\u5b9e\u73b0 3 \u500d\u7684\u901f\u5ea6\u3002\u5728 Mustang \u7684\u540e\u7eed\u7248\u672c\uff08\u4ee3\u7801\u540d\u79f0\u4e3a Dolphin\uff09\u4e2d\uff0c\u5df2\u7ecf\u89c4\u5212\u4e86\u8fdb\u4e00\u6b65\u7684\u6539\u8fdb\u3002<\/p>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>\u539f\u6587\u5730\u5740 &nbsp; \u9501\uff08lock\uff09\u7684<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"colormag_page_container_layout":"default_layout","colormag_page_sidebar_layout":"default_layout","footnotes":""},"categories":[],"tags":[119],"class_list":["post-4304","post","type-post","status-publish","format-standard","hentry","tag-03-"],"_links":{"self":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/posts\/4304","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/comments?post=4304"}],"version-history":[{"count":0,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/posts\/4304\/revisions"}],"wp:attachment":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/media?parent=4304"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/categories?post=4304"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/tags?post=4304"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}