{"id":3315,"date":"2018-11-05T10:11:55","date_gmt":"2018-11-05T02:11:55","guid":{"rendered":"http:\/\/www.xttblog.com\/?p=3315"},"modified":"2018-11-05T10:11:55","modified_gmt":"2018-11-05T02:11:55","slug":"java%e5%b9%b6%e5%8f%91%e4%b9%8bcpu%e7%bc%93%e5%ad%98%e4%b8%80%e8%87%b4%e6%80%a7","status":"publish","type":"post","link":"https:\/\/www.xttblog.com\/?p=3315","title":{"rendered":"Java\u5e76\u53d1\u4e4bCPU\u7f13\u5b58\u4e00\u81f4\u6027"},"content":{"rendered":"<p>\n\t\u53ea\u5b66\u4e60\u7f13\u5b58\u6846\u67b6\u7684\u4f7f\u7528\uff0c\u800c\u4e0d\u4e86\u89e3\u7f13\u5b58\u7684\u5e95\u5c42\u5b9e\u73b0\u903b\u8f91\uff0c\u5bf9\u4e8e\u9ad8\u7ea7\u5f00\u53d1\u6765\u8bf4\u592a\u6ca1\u7406\u60f3\u4e86\uff01\u4eca\u5929\u6211\u4eec\u6765\u804a\u804aCPU\u7684\u7f13\u5b58\u4e00\u81f4\u6027\uff01\n<\/p>\n<p>\n\t\u51c6\u786e\u7684\u8bf4\uff0c\u6211\u4eec\u4eca\u5929\u8981\u804a\u7684\u662fCPU\u7f13\u5b58\u4e00\u81f4\u6027\u534f\u8baeMESI\u3002\n<\/p>\n<h2>\n\t\u4e3a\u4ec0\u4e48CPU\u9700\u8981\u9ad8\u901f\u7f13\u5b58\uff1f<br \/>\n<\/h2>\n<p>\n\t\u5728\u6469\u5c14\u5b9a\u5f8b\u7684\u6307\u5bfc\u4e0bCPU\u4ee5\u6bcf18\u4e2a\u6708\u7ffb\u4e00\u756a\u7684\u901f\u5ea6\u5728\u53d1\u5c55\uff0c\u7136\u800c\u5185\u5b58\u548c\u786c\u76d8\u7684\u53d1\u5c55\u901f\u5ea6\u8fdc\u8fdc\u4e0d\u53caCPU\u3002\u8fd9\u5c31\u9020\u6210\u4e86\u9ad8\u6027\u80fd\u80fd\u7684\u5185\u5b58\u548c\u786c\u76d8\u4ef7\u683c\u53ca\u5176\u6602\u8d35\u3002\u7136\u800cCPU\u7684\u9ad8\u5ea6\u8fd0\u7b97\u9700\u8981\u9ad8\u901f\u7684\u6570\u636e\u3002\u4e3a\u4e86\u89e3\u51b3\u8fd9\u4e2a\u95ee\u9898\uff0cCPU\u5382\u5546\u5728CPU\u4e2d\u5185\u7f6e\u4e86\u5c11\u91cf\u7684\u9ad8\u901f\u7f13\u5b58\u4ee5\u89e3\u51b3 IO \u901f\u5ea6\u548c CPU \u8fd0\u7b97\u901f\u5ea6\u4e4b\u95f4\u7684\u4e0d\u5339\u914d\u95ee\u9898\u3002\n<\/p>\n<p>\n\t\u5728CPU\u8bbf\u95ee\u5b58\u50a8\u8bbe\u5907\u65f6\uff0c\u65e0\u8bba\u662f\u5b58\u53d6\u6570\u636e\u6291\u6216\u5b58\u53d6\u6307\u4ee4\uff0c\u90fd\u8d8b\u4e8e\u805a\u96c6\u5728\u4e00\u7247\u8fde\u7eed\u7684\u533a\u57df\u4e2d\uff0c\u8fd9\u5c31\u88ab\u79f0\u4e3a\u5c40\u90e8\u6027\u539f\u7406\u3002\n<\/p>\n<p>\n\t\u65f6\u95f4\u5c40\u90e8\u6027\uff08Temporal Locality\uff09\uff1a<span style=\"color:#0000CD\"><strong>\u5982\u679c\u4e00\u4e2a\u4fe1\u606f\u9879\u6b63\u5728\u88ab\u8bbf\u95ee\uff0c\u90a3\u4e48\u5728\u8fd1\u671f\u5b83\u5f88\u53ef\u80fd\u8fd8\u4f1a\u88ab\u518d\u6b21\u8bbf\u95ee<\/strong><\/span>\u3002\u6bd4\u5982\u5faa\u73af\u3001\u9012\u5f52\u3001\u65b9\u6cd5\u7684\u53cd\u590d\u8c03\u7528\u7b49\u3002\n<\/p>\n<p>\n\t\u7a7a\u95f4\u5c40\u90e8\u6027\uff08Spatial Locality\uff09\uff1a<span style=\"color:#0000CD\"><strong>\u5982\u679c\u4e00\u4e2a\u5b58\u50a8\u5668\u7684\u4f4d\u7f6e\u88ab\u5f15\u7528\uff0c\u90a3\u4e48\u5c06\u6765\u4ed6\u9644\u8fd1\u7684\u4f4d\u7f6e\u4e5f\u4f1a\u88ab\u5f15\u7528<\/strong><\/span>\u3002\u6bd4\u5982\u987a\u5e8f\u6267\u884c\u7684\u4ee3\u7801\u3001\u8fde\u7eed\u521b\u5efa\u7684\u4e24\u4e2a\u5bf9\u8c61\u3001\u6570\u7ec4\u7b49\u3002\n<\/p>\n<h2>\n\tCPU\u9ad8\u901f\u7f13\u5b58\u7684\u6267\u884c\u8ba1\u7b97\u7684\u6d41\u7a0b<br \/>\n<\/h2>\n<ul>\n<li>\n\t\t\u7a0b\u5e8f\u4ee5\u53ca\u6570\u636e\u88ab\u52a0\u8f7d\u5230\u4e3b\u5185\u5b58\n\t<\/li>\n<li>\n\t\t\u6307\u4ee4\u548c\u6570\u636e\u88ab\u52a0\u8f7d\u5230CPU\u7684\u9ad8\u901f\u7f13\u5b58\n\t<\/li>\n<li>\n\t\tCPU\u6267\u884c\u6307\u4ee4\uff0c\u628a\u7ed3\u679c\u5199\u5230\u9ad8\u901f\u7f13\u5b58\n\t<\/li>\n<li>\n\t\t\u9ad8\u901f\u7f13\u5b58\u4e2d\u7684\u6570\u636e\u5199\u56de\u4e3b\u5185\u5b58\n\t<\/li>\n<\/ul>\n<p>\n\t<img decoding=\"async\" alt=\"CPU \u9ad8\u901f\u7f13\u5b58\u6267\u884c\u6280\u672f\u7684\u6d41\u7a0b\" src=\"https:\/\/raw.githubusercontent.com\/xmt1139057136\/xttblog\/master\/cpu-cache.png\" style=\"width: 674px;height: 364px\" \/>\n<\/p>\n<h2>\n\t\u6d41\u884c\u7684\u591a\u7ea7\u7f13\u5b58\u7ed3\u6784<br \/>\n<\/h2>\n<p>\n\t\u7531\u4e8eCPU\u7684\u8fd0\u7b97\u901f\u5ea6\u8d85\u8d8a\u4e861\u7ea7\u7f13\u5b58\u7684\u6570\u636eIO\u80fd\u529b\uff0cCPU\u5382\u5546\u53c8\u5f15\u5165\u4e86\u591a\u7ea7\u7684\u7f13\u5b58\u7ed3\u6784\u3002CPU\u7684\u591a\u7ea7\u7f13\u5b58\u7ed3\u6784\u5982\u4e0b\u56fe\u6240\u793a\uff1a\n<\/p>\n<p>\n\t<img decoding=\"async\" alt=\"CPU \u7684\u591a\u7ea7\u7f13\u5b58\u7ed3\u6784\" src=\"https:\/\/raw.githubusercontent.com\/xmt1139057136\/xttblog\/master\/cpu-l-cache.png\" style=\"width: 670px;height: 700px\" \/>\n<\/p>\n<h2>\n\t\u591a\u6838CPU\u591a\u7ea7\u7f13\u5b58\u4e00\u81f4\u6027\u534f\u8baeMESI<br \/>\n<\/h2>\n<p>\n\t\u591a\u6838CPU\u7684\u60c5\u51b5\u4e0b\u6709\u591a\u4e2a\u4e00\u7ea7\u7f13\u5b58\uff0c\u5982\u4f55\u4fdd\u8bc1\u7f13\u5b58\u5185\u90e8\u6570\u636e\u7684\u4e00\u81f4,\u4e0d\u8ba9\u7cfb\u7edf\u6570\u636e\u6df7\u4e71\u3002\u8fd9\u91cc\u5c31\u5f15\u51fa\u4e86\u4e00\u4e2a\u4e00\u81f4\u6027\u7684\u534f\u8baeMESI\u3002\n<\/p>\n<p>\n\tMESI\u662f\u75314\u4e2a\u72b6\u6001\u7684\u9996\u5b57\u6bcd\u7ec4\u6210\u7684\u3002\u6bcf\u4e2aCache line\u67094\u4e2a\u72b6\u6001\uff0c\u53ef\u75282\u4e2abit\u8868\u793a\uff0c\u5b83\u4eec\u5206\u522b\u662f\uff1a\n<\/p>\n<table>\n<thead>\n<tr>\n<th>\n\t\t\t\t\u72b6\u6001\n\t\t\t<\/th>\n<th>\n\t\t\t\t\u63cf\u8ff0\n\t\t\t<\/th>\n<th>\n\t\t\t\t\u76d1\u542c\u4efb\u52a1\n\t\t\t<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>\n\t\t\t\tM \u4fee\u6539 (Modified)\n\t\t\t<\/td>\n<td>\n\t\t\t\t\u8be5Cache line\u6709\u6548\uff0c\u6570\u636e\u88ab\u4fee\u6539\u4e86\uff0c\u548c\u5185\u5b58\u4e2d\u7684\u6570\u636e\u4e0d\u4e00\u81f4\uff0c\u6570\u636e\u53ea\u5b58\u5728\u4e8e\u672cCache\u4e2d\u3002\n\t\t\t<\/td>\n<td>\n\t\t\t\t\u7f13\u5b58\u884c\u5fc5\u987b\u65f6\u523b\u76d1\u542c\u6240\u6709\u8bd5\u56fe\u8bfb\u8be5\u7f13\u5b58\u884c\u76f8\u5bf9\u5c31\u4e3b\u5b58\u7684\u64cd\u4f5c\uff0c\u8fd9\u79cd\u64cd\u4f5c\u5fc5\u987b\u5728\u7f13\u5b58\u5c06\u8be5\u7f13\u5b58\u884c\u5199\u56de\u4e3b\u5b58\u5e76\u5c06\u72b6\u6001\u53d8\u6210S\uff08\u5171\u4eab\uff09\u72b6\u6001\u4e4b\u524d\u88ab\u5ef6\u8fdf\u6267\u884c\u3002\n\t\t\t<\/td>\n<\/tr>\n<tr>\n<td>\n\t\t\t\tE \u72ec\u4eab\u3001\u4e92\u65a5 (Exclusive)\n\t\t\t<\/td>\n<td>\n\t\t\t\t\u8be5Cache line\u6709\u6548\uff0c\u6570\u636e\u548c\u5185\u5b58\u4e2d\u7684\u6570\u636e\u4e00\u81f4\uff0c\u6570\u636e\u53ea\u5b58\u5728\u4e8e\u672cCache\u4e2d\u3002\n\t\t\t<\/td>\n<td>\n\t\t\t\t\u7f13\u5b58\u884c\u4e5f\u5fc5\u987b\u76d1\u542c\u5176\u5b83\u7f13\u5b58\u8bfb\u4e3b\u5b58\u4e2d\u8be5\u7f13\u5b58\u884c\u7684\u64cd\u4f5c\uff0c\u4e00\u65e6\u6709\u8fd9\u79cd\u64cd\u4f5c\uff0c\u8be5\u7f13\u5b58\u884c\u9700\u8981\u53d8\u6210S\uff08\u5171\u4eab\uff09\u72b6\u6001\u3002\n\t\t\t<\/td>\n<\/tr>\n<tr>\n<td>\n\t\t\t\tS \u5171\u4eab (Shared)\n\t\t\t<\/td>\n<td>\n\t\t\t\t\u8be5Cache line\u6709\u6548\uff0c\u6570\u636e\u548c\u5185\u5b58\u4e2d\u7684\u6570\u636e\u4e00\u81f4\uff0c\u6570\u636e\u5b58\u5728\u4e8e\u5f88\u591aCache\u4e2d\u3002\n\t\t\t<\/td>\n<td>\n\t\t\t\t\u7f13\u5b58\u884c\u4e5f\u5fc5\u987b\u76d1\u542c\u5176\u5b83\u7f13\u5b58\u4f7f\u8be5\u7f13\u5b58\u884c\u65e0\u6548\u6216\u8005\u72ec\u4eab\u8be5\u7f13\u5b58\u884c\u7684\u8bf7\u6c42\uff0c\u5e76\u5c06\u8be5\u7f13\u5b58\u884c\u53d8\u6210\u65e0\u6548\uff08Invalid\uff09\u3002\n\t\t\t<\/td>\n<\/tr>\n<tr>\n<td>\n\t\t\t\tI \u65e0\u6548 (Invalid)\n\t\t\t<\/td>\n<td>\n\t\t\t\t\u8be5Cache line\u65e0\u6548\u3002\n\t\t\t<\/td>\n<td>\n\t\t\t\t\u65e0\n\t\t\t<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>\n\tCache line \u662f\u7f13\u5b58\u884c\u3002\u662f\u7f13\u5b58\u5b58\u50a8\u6570\u636e\u7684\u5355\u5143\u3002\n<\/p>\n<p>\n\t\u5bf9\u4e8e Modified \u548c Exclusive \u72b6\u6001\u800c\u8a00\u603b\u662f\u7cbe\u786e\u7684\uff0c\u4ed6\u4eec\u5728\u548c\u8be5\u7f13\u5b58\u884c\u7684\u771f\u6b63\u72b6\u6001\u662f\u4e00\u81f4\u7684\uff0c\u800c Shared \u72b6\u6001\u53ef\u80fd\u662f\u975e\u4e00\u81f4\u7684\u3002\u5982\u679c\u4e00\u4e2a\u7f13\u5b58\u5c06\u5904\u4e8e Shared \u72b6\u6001\u7684\u7f13\u5b58\u884c\u4f5c\u5e9f\u4e86\uff0c\u800c\u53e6\u4e00\u4e2a\u7f13\u5b58\u5b9e\u9645\u4e0a\u53ef\u80fd\u5df2\u7ecf\u72ec\u4eab\u4e86\u8be5\u7f13\u5b58\u884c\uff0c\u4f46\u662f\u8be5\u7f13\u5b58\u5374\u4e0d\u4f1a\u5c06\u8be5\u7f13\u5b58\u884c\u5347\u8fc1\u4e3a Exclusive \u72b6\u6001\uff0c\u8fd9\u662f\u56e0\u4e3a\u5176\u5b83\u7f13\u5b58\u4e0d\u4f1a\u5e7f\u64ad\u4ed6\u4eec\u4f5c\u5e9f\u6389\u8be5\u7f13\u5b58\u884c\u7684\u901a\u77e5\uff0c\u540c\u6837\u7531\u4e8e\u7f13\u5b58\u5e76\u6ca1\u6709\u4fdd\u5b58\u8be5\u7f13\u5b58\u884c\u7684copy\u7684\u6570\u91cf\uff0c\u56e0\u6b64\uff08\u5373\u4f7f\u6709\u8fd9\u79cd\u901a\u77e5\uff09\u4e5f\u6ca1\u6709\u529e\u6cd5\u786e\u5b9a\u81ea\u5df1\u662f\u5426\u5df2\u7ecf\u72ec\u4eab\u4e86\u8be5\u7f13\u5b58\u884c\u3002\n<\/p>\n<p>\n\t\u4ece\u4e0a\u9762\u7684\u610f\u4e49\u770b\u6765E\u72b6\u6001\u662f\u4e00\u79cd\u6295\u673a\u6027\u7684\u4f18\u5316\uff1a\u5982\u679c\u4e00\u4e2aCPU\u60f3\u4fee\u6539\u4e00\u4e2a\u5904\u4e8e Shared \u72b6\u6001\u7684\u7f13\u5b58\u884c\uff0c\u603b\u7ebf\u4e8b\u52a1\u9700\u8981\u5c06\u6240\u6709\u8be5\u7f13\u5b58\u884c\u7684copy\u53d8\u6210invalid\u72b6\u6001\uff0c\u800c\u4fee\u6539E\u72b6\u6001\u7684\u7f13\u5b58\u4e0d\u9700\u8981\u4f7f\u7528\u603b\u7ebf\u4e8b\u52a1\u3002\n<\/p>\n<h2>\n\tMESI\u72b6\u6001\u8f6c\u6362<br \/>\n<\/h2>\n<p>\n\t<img decoding=\"async\" alt=\"MESI\u72b6\u6001\u8f6c\u6362\" src=\"https:\/\/raw.githubusercontent.com\/xmt1139057136\/xttblog\/master\/mesi.png\" style=\"width: 1196px;height: 546px\" \/>\n<\/p>\n<p>\n\t\u5728\u7406\u89e3\u8be5\u56fe\u524d\uff0c\u6211\u4eec\u5148\u6765\u770b\u4e00\u4e0b\u4ec0\u4e48\u662f\u672c\u5730\u8bfb\u53d6\uff08Local read\uff09\u3001\u672c\u5730\u5199\u5165\uff08Local write\uff09\u3001\u8fdc\u7aef\u8bfb\u53d6\uff08Remote read\uff09\u3001\u8fdc\u7aef\u5199\u5165\uff08Remote write\uff09\u3002\n<\/p>\n<h2>\n\tMESI\u72b6\u6001\u8f6c\u6362\u7684\u89e6\u53d1\u4e8b\u4ef6<br \/>\n<\/h2>\n<p>\n\t<img decoding=\"async\" alt=\"MESI\u72b6\u6001\u8f6c\u6362\u7684\u89e6\u53d1\u4e8b\u4ef6\" src=\"https:\/\/raw.githubusercontent.com\/xmt1139057136\/xttblog\/master\/cpu-cache-rwx.png\" style=\"width: 389px;height: 211px\" \/>\n<\/p>\n<h2>\n\tcache \u7f13\u5b58\u5206\u7c7b<br \/>\n<\/h2>\n<p>\n\t\u524d\u63d0\uff1a\u6240\u6709\u7684cache\u5171\u540c\u7f13\u5b58\u4e86\u4e3b\u5185\u5b58\u4e2d\u7684\u67d0\u4e00\u6761\u6570\u636e\u3002\n<\/p>\n<p>\n\t\u672c\u5730cache:\u6307\u5f53\u524dcpu\u7684cache\u3002<br \/>\n\t\u89e6\u53d1cache:\u89e6\u53d1\u8bfb\u5199\u4e8b\u4ef6\u7684cache\u3002<br \/>\n\t\u5176\u4ed6cache:\u6307\u65e2\u9664\u4e86\u4ee5\u4e0a\u4e24\u79cd\u4e4b\u5916\u7684cache\u3002<br \/>\n\t\u6ce8\u610f\uff1a\u672c\u5730\u7684\u4e8b\u4ef6\u89e6\u53d1 \u672c\u5730cache\u548c\u89e6\u53d1cache\u4e3a\u76f8\u540c\u3002\n<\/p>\n<p>\n\t\u4e0a\u9762\u7684MESI\u72b6\u6001\u8f6c\u6362\u56fe\u5207\u6362\u89e3\u91ca\uff1a\n<\/p>\n<table>\n<thead>\n<tr>\n<th>\n\t\t\t\t\u72b6\u6001\n\t\t\t<\/th>\n<th>\n\t\t\t\t\u89e6\u53d1\u672c\u5730\u8bfb\u53d6\n\t\t\t<\/th>\n<th>\n\t\t\t\t\u89e6\u53d1\u672c\u5730\u5199\u5165\n\t\t\t<\/th>\n<th>\n\t\t\t\t\u89e6\u53d1\u8fdc\u7aef\u8bfb\u53d6\n\t\t\t<\/th>\n<th>\n\t\t\t\t\u89e6\u53d1\u8fdc\u7aef\u5199\u5165\n\t\t\t<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>\n\t\t\t\t<strong>M\u72b6\u6001\uff08\u4fee\u6539\uff09<\/strong>\n\t\t\t<\/td>\n<td>\n\t\t\t\t\u672c\u5730cache:M&nbsp;<br \/>\n\t\t\t\t\u89e6\u53d1cache:M<br \/>\n\t\t\t\t\u5176\u4ed6cache:I\n\t\t\t<\/td>\n<td>\n\t\t\t\t\u672c\u5730cache:M&nbsp;<br \/>\n\t\t\t\t\u89e6\u53d1cache:M<br \/>\n\t\t\t\t\u5176\u4ed6cache:I\n\t\t\t<\/td>\n<td>\n\t\t\t\t\u672c\u5730cache:M&rarr;E&rarr;S<br \/>\n\t\t\t\t\u89e6\u53d1cache:I&rarr;S<br \/>\n\t\t\t\t\u5176\u4ed6cache:I&rarr;S<br \/>\n\t\t\t\t\u540c\u6b65\u4e3b\u5185\u5b58\u540e\u4fee\u6539\u4e3aE\u72ec\u4eab,\u540c\u6b65\u89e6\u53d1\u3001\u5176\u4ed6cache\u540e\u672c\u5730\u3001\u89e6\u53d1\u3001\u5176\u4ed6cache\u4fee\u6539\u4e3aS\u5171\u4eab\n\t\t\t<\/td>\n<td>\n\t\t\t\t\u672c\u5730cache:M&rarr;E&rarr;S&rarr;I<br \/>\n\t\t\t\t\u89e6\u53d1cache:I&rarr;S&rarr;E&rarr;M<br \/>\n\t\t\t\t\u5176\u4ed6cache:I&rarr;S&rarr;I<br \/>\n\t\t\t\t\u540c\u6b65\u548c\u8bfb\u53d6\u4e00\u6837,\u540c\u6b65\u5b8c\u6210\u540e\u89e6\u53d1cache\u6539\u4e3aM\uff0c\u672c\u5730\u3001\u5176\u4ed6cache\u6539\u4e3aI\n\t\t\t<\/td>\n<\/tr>\n<tr>\n<td>\n\t\t\t\t<strong>E\u72b6\u6001\uff08\u72ec\u4eab\uff09<\/strong>\n\t\t\t<\/td>\n<td>\n\t\t\t\t\u672c\u5730cache:E<br \/>\n\t\t\t\t\u89e6\u53d1cache:E<br \/>\n\t\t\t\t\u5176\u4ed6cache:I\n\t\t\t<\/td>\n<td>\n\t\t\t\t\u672c\u5730cache:E&rarr;M<br \/>\n\t\t\t\t\u89e6\u53d1cache:E&rarr;M<br \/>\n\t\t\t\t\u5176\u4ed6cache:I<br \/>\n\t\t\t\t\u672c\u5730cache\u53d8\u66f4\u4e3aM,\u5176\u4ed6cache\u72b6\u6001\u5e94\u5f53\u662fI\uff08\u65e0\u6548\uff09\n\t\t\t<\/td>\n<td>\n\t\t\t\t\u672c\u5730cache:E&rarr;S<br \/>\n\t\t\t\t\u89e6\u53d1cache:I&rarr;S<br \/>\n\t\t\t\t\u5176\u4ed6cache:I&rarr;S<br \/>\n\t\t\t\t\u5f53\u5176\u4ed6cache\u8981\u8bfb\u53d6\u8be5\u6570\u636e\u65f6\uff0c\u5176\u4ed6\u3001\u89e6\u53d1\u3001\u672c\u5730cache\u90fd\u88ab\u8bbe\u7f6e\u4e3aS(\u5171\u4eab)\n\t\t\t<\/td>\n<td>\n\t\t\t\t\u672c\u5730cache:E&rarr;S&rarr;I<br \/>\n\t\t\t\t\u89e6\u53d1cache:I&rarr;S&rarr;E&rarr;M<br \/>\n\t\t\t\t\u5176\u4ed6cache:I&rarr;S&rarr;I<br \/>\n\t\t\t\t\u5f53\u89e6\u53d1cache\u4fee\u6539\u672c\u5730cache\u72ec\u4eab\u6570\u636e\u65f6\u65f6\uff0c\u5c06\u672c\u5730\u3001\u89e6\u53d1\u3001\u5176\u4ed6cache\u4fee\u6539\u4e3aS\u5171\u4eab.\u7136\u540e\u89e6\u53d1cache\u4fee\u6539\u4e3a\u72ec\u4eab\uff0c\u5176\u4ed6\u3001\u672c\u5730cache\u4fee\u6539\u4e3aI\uff08\u65e0\u6548\uff09\uff0c\u89e6\u53d1cache\u518d\u4fee\u6539\u4e3aM\n\t\t\t<\/td>\n<\/tr>\n<tr>\n<td>\n\t\t\t\t<strong>S\u72b6\u6001(\u5171\u4eab)<\/strong>\n\t\t\t<\/td>\n<td>\n\t\t\t\t\u672c\u5730cache:S<br \/>\n\t\t\t\t\u89e6\u53d1cache:S<br \/>\n\t\t\t\t\u5176\u4ed6cache:S\n\t\t\t<\/td>\n<td>\n\t\t\t\t\u672c\u5730cache:S&rarr;E&rarr;M<br \/>\n\t\t\t\t\u89e6\u53d1cache:S&rarr;E&rarr;M<br \/>\n\t\t\t\t\u5176\u4ed6cache:S&rarr;I&nbsp;<br \/>\n\t\t\t\t\u5f53\u672c\u5730cache\u4fee\u6539\u65f6\uff0c\u5c06\u672c\u5730cache\u4fee\u6539\u4e3aE,\u5176\u4ed6cache\u4fee\u6539\u4e3aI,\u7136\u540e\u518d\u5c06\u672c\u5730cache\u4e3aM\u72b6\u6001\n\t\t\t<\/td>\n<td>\n\t\t\t\t\u672c\u5730cache:S<br \/>\n\t\t\t\t\u89e6\u53d1cache:S<br \/>\n\t\t\t\t\u5176\u4ed6cache:S\n\t\t\t<\/td>\n<td>\n\t\t\t\t\u672c\u5730cache:S&rarr;I<br \/>\n\t\t\t\t\u89e6\u53d1cache\uff1aS&rarr;E&rarr;M<br \/>\n\t\t\t\t\u5176\u4ed6cache:S&rarr;I<br \/>\n\t\t\t\t\u5f53\u89e6\u53d1cache\u8981\u4fee\u6539\u672c\u5730\u5171\u4eab\u6570\u636e\u65f6\uff0c\u89e6\u53d1cache\u4fee\u6539\u4e3aE\uff08\u72ec\u4eab\uff09,\u672c\u5730\u3001\u5176\u4ed6cache\u4fee\u6539\u4e3aI\uff08\u65e0\u6548\uff09,\u89e6\u53d1cache\u518d\u6b21\u4fee\u6539\u4e3aM(\u4fee\u6539)\n\t\t\t<\/td>\n<\/tr>\n<tr>\n<td>\n\t\t\t\t<strong>I\u72b6\u6001\uff08\u65e0\u6548\uff09<\/strong>\n\t\t\t<\/td>\n<td>\n\t\t\t\t\u672c\u5730cache:I&rarr;S\u6216\u8005I&rarr;E<br \/>\n\t\t\t\t\u89e6\u53d1cache:I&rarr;S\u6216\u8005I &rarr;E<br \/>\n\t\t\t\t\u5176\u4ed6cache:E\u3001M\u3001I&rarr;S\u3001I<br \/>\n\t\t\t\t\u672c\u5730\u3001\u89e6\u53d1cache\u5c06\u4eceI\u65e0\u6548\u4fee\u6539\u4e3aS\u5171\u4eab\u6216\u8005E\u72ec\u4eab\uff0c\u5176\u4ed6cache\u5c06\u4eceE\u3001M\u3001I \u53d8\u4e3aS\u6216\u8005I\n\t\t\t<\/td>\n<td>\n\t\t\t\t\u672c\u5730cache:I&rarr;S&rarr;E&rarr;M<br \/>\n\t\t\t\t\u89e6\u53d1cache:I&rarr;S&rarr;E&rarr;M<br \/>\n\t\t\t\t\u5176\u4ed6cache:M\u3001E\u3001S&rarr;S&rarr;I\n\t\t\t<\/td>\n<td>\n\t\t\t\t\u65e2\u7136\u662f\u672ccache\u662fI\uff0c\u5176\u4ed6cache\u64cd\u4f5c\u4e0e\u5b83\u65e0\u5173\n\t\t\t<\/td>\n<td>\n\t\t\t\t\u65e2\u7136\u662f\u672ccache\u662fI\uff0c\u5176\u4ed6cache\u64cd\u4f5c\u4e0e\u5b83\u65e0\u5173\n\t\t\t<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>\n\t\u5f53\u4e00\u4e2acache line\u7684\u8c03\u6574\u7684\u72b6\u6001\u7684\u65f6\u5019\uff0c\u53e6\u5916\u4e00\u4e2a cache line \u4e5f\u9700\u8981\u8c03\u6574\u7684\u72b6\u6001\u3002\n<\/p>\n<p>\n\t<img decoding=\"async\" alt=\"cache line\u7684\u72b6\u6001\u8c03\u6574\" src=\"https:\/\/raw.githubusercontent.com\/xmt1139057136\/xttblog\/master\/cpu-cache-line.png\" style=\"width: 239px;height: 207px\" \/>\n<\/p>\n<p>\n\t\u4e3e\u4e2a\u6817\u5b50\u6765\u8bf4\uff1a\n<\/p>\n<p>\n\t\u5047\u8bbecache 1 \u4e2d\u6709\u4e00\u4e2a\u53d8\u91cfx = 0\u7684cache line \u5904\u4e8eS\u72b6\u6001(\u5171\u4eab)\u3002<br \/>\n\t\u90a3\u4e48\u5176\u4ed6\u62e5\u6709x\u53d8\u91cf\u7684cache 2\u3001cache 3\u7b49x\u7684cache line\u8c03\u6574\u4e3aS\u72b6\u6001\uff08\u5171\u4eab\uff09\u6216\u8005\u8c03\u6574\u4e3a I \u72b6\u6001\uff08\u65e0\u6548\uff09\u3002\n<\/p>\n<h2>\n\t\u591a\u6838\u7f13\u5b58\u534f\u540c\u64cd\u4f5c<br \/>\n<\/h2>\n<p>\n\t\u5047\u8bbe\u6709\u4e09\u4e2aCPU A\u3001B\u3001C\uff0c\u5bf9\u5e94\u4e09\u4e2a\u7f13\u5b58\u5206\u522b\u662fcache a\u3001b\u3001 c\u3002\u5728\u4e3b\u5185\u5b58\u4e2d\u5b9a\u4e49\u4e86x\u7684\u5f15\u7528\u503c\u4e3a0\u3002\n<\/p>\n<p>\n\t<img decoding=\"async\" alt=\"\u591a\u6838\u7f13\u5b58\u534f\u540c\u64cd\u4f5c\" src=\"https:\/\/raw.githubusercontent.com\/xmt1139057136\/xttblog\/master\/cpu-bus.png\" style=\"width: 910px;height: 914px\" \/>\n<\/p>\n<h2>\n\t\u5355\u6838\u8bfb\u53d6<br \/>\n<\/h2>\n<p>\n\t\u5355\u6838\u8bfb\u53d6\u5c31\u6ca1\u6709\u534f\u540c\u6982\u5ff5\u4e86\u3002\u90a3\u4e48\u6267\u884c\u6d41\u7a0b\u662f\uff1aCPU A\u53d1\u51fa\u4e86\u4e00\u6761\u6307\u4ee4\uff0c\u4ece\u4e3b\u5185\u5b58\u4e2d\u8bfb\u53d6x\u3002\u4ece\u4e3b\u5185\u5b58\u901a\u8fc7bus\u8bfb\u53d6\u5230\u7f13\u5b58\u4e2d\uff08\u8fdc\u7aef\u8bfb\u53d6Remote read\uff09,\u8fd9\u662f\u8be5Cache line\u4fee\u6539\u4e3aE\u72b6\u6001\uff08\u72ec\u4eab\uff09\u3002\n<\/p>\n<p>\n\t<img decoding=\"async\" alt=\"CPU\u5355\u6838\u8bfb\u53d6 \" src=\"https:\/\/raw.githubusercontent.com\/xmt1139057136\/xttblog\/master\/cpu-core.png\" style=\"width: 898px;height: 884px\" \/>\n<\/p>\n<h2>\n\t\u53cc\u6838\u8bfb\u53d6<br \/>\n<\/h2>\n<p>\n\t\u90a3\u4e48\u6267\u884c\u6d41\u7a0b\u662f\uff1a<br \/>\n\tCPU A\u53d1\u51fa\u4e86\u4e00\u6761\u6307\u4ee4\uff0c\u4ece\u4e3b\u5185\u5b58\u4e2d\u8bfb\u53d6x\u3002<br \/>\n\tCPU A\u4ece\u4e3b\u5185\u5b58\u901a\u8fc7bus\u8bfb\u53d6\u5230 cache a\u4e2d\u5e76\u5c06\u8be5cache line \u8bbe\u7f6e\u4e3aE\u72b6\u6001\u3002<br \/>\n\tCPU B\u53d1\u51fa\u4e86\u4e00\u6761\u6307\u4ee4\uff0c\u4ece\u4e3b\u5185\u5b58\u4e2d\u8bfb\u53d6x\u3002<br \/>\n\tCPU B\u8bd5\u56fe\u4ece\u4e3b\u5185\u5b58\u4e2d\u8bfb\u53d6x\u65f6\uff0cCPU A\u68c0\u6d4b\u5230\u4e86\u5730\u5740\u51b2\u7a81\u3002\u8fd9\u65f6CPU A\u5bf9\u76f8\u5173\u6570\u636e\u505a\u51fa\u54cd\u5e94\u3002\u6b64\u65f6x \u5b58\u50a8\u4e8ecache a\u548ccache b\u4e2d\uff0cx\u5728chche a\u548ccache b\u4e2d\u90fd\u88ab\u8bbe\u7f6e\u4e3aS\u72b6\u6001(\u5171\u4eab)\u3002\n<\/p>\n<p>\n\t<img decoding=\"async\" alt=\"CPU\u53cc\u6838\u8bfb\u53d6\" src=\"https:\/\/raw.githubusercontent.com\/xmt1139057136\/xttblog\/master\/cpu-core-bus.png\" style=\"width: 888px;height: 878px\" \/>\n<\/p>\n<h2>\n\tCPU\u4fee\u6539\u6570\u636e<br \/>\n<\/h2>\n<p>\n\t\u90a3\u4e48\u6267\u884c\u6d41\u7a0b\u662f\uff1a<br \/>\n\tCPU A \u8ba1\u7b97\u5b8c\u6210\u540e\u53d1\u6307\u4ee4\u9700\u8981\u4fee\u6539x.<br \/>\n\tCPU A \u5c06x\u8bbe\u7f6e\u4e3aM\u72b6\u6001\uff08\u4fee\u6539\uff09\u5e76\u901a\u77e5\u7f13\u5b58\u4e86x\u7684CPU B, CPU B\u5c06\u672c\u5730cache b\u4e2d\u7684x\u8bbe\u7f6e\u4e3aI\u72b6\u6001(\u65e0\u6548)<br \/>\n\tCPU A \u5bf9x\u8fdb\u884c\u8d4b\u503c\u3002\n<\/p>\n<p>\n\t<img decoding=\"async\" alt=\"CPU\u4fee\u6539\u6570\u636e\" src=\"https:\/\/raw.githubusercontent.com\/xmt1139057136\/xttblog\/master\/cpu-update-data.png\" style=\"width: 876px;height: 872px\" \/>\n<\/p>\n<h2>\n\t\u540c\u6b65\u6570\u636e<br \/>\n<\/h2>\n<p>\n\t\u90a3\u4e48\u6267\u884c\u6d41\u7a0b\u662f\uff1aCPU B \u53d1\u51fa\u4e86\u8981\u8bfb\u53d6x\u7684\u6307\u4ee4\u3002CPU B \u901a\u77e5CPU A,CPU A\u5c06\u4fee\u6539\u540e\u7684\u6570\u636e\u540c\u6b65\u5230\u4e3b\u5185\u5b58\u65f6cache a \u4fee\u6539\u4e3aE\uff08\u72ec\u4eab\uff09CPU A\u540c\u6b65CPU B\u7684x,\u5c06cache a\u548c\u540c\u6b65\u540ecache b\u4e2d\u7684x\u8bbe\u7f6e\u4e3aS\u72b6\u6001\uff08\u5171\u4eab\uff09\u3002\n<\/p>\n<p>\n\t<img decoding=\"async\" alt=\"CPU\u540c\u6b65\u6570\u636e\" src=\"https:\/\/raw.githubusercontent.com\/xmt1139057136\/xttblog\/master\/cpu-m-s.png\" style=\"width: 872px;height: 866px\" \/>\n<\/p>\n<h2>\n\tMESI\u4f18\u5316\u548c\u4ed6\u4eec\u5f15\u5165\u7684\u95ee\u9898<br \/>\n<\/h2>\n<p>\n\t\u7f13\u5b58\u7684\u4e00\u81f4\u6027\u6d88\u606f\u4f20\u9012\u662f\u8981\u65f6\u95f4\u7684\uff0c\u8fd9\u5c31\u4f7f\u5176\u5207\u6362\u65f6\u4f1a\u4ea7\u751f\u5ef6\u8fdf\u3002\u5f53\u4e00\u4e2a\u7f13\u5b58\u88ab\u5207\u6362\u72b6\u6001\u65f6\u5176\u4ed6\u7f13\u5b58\u6536\u5230\u6d88\u606f\u5b8c\u6210\u5404\u81ea\u7684\u5207\u6362\u5e76\u4e14\u53d1\u51fa\u56de\u5e94\u6d88\u606f\u8fd9\u4e48\u4e00\u957f\u4e32\u7684\u65f6\u95f4\u4e2dCPU\u90fd\u4f1a\u7b49\u5f85\u6240\u6709\u7f13\u5b58\u54cd\u5e94\u5b8c\u6210\u3002\u53ef\u80fd\u51fa\u73b0\u7684\u963b\u585e\u90fd\u4f1a\u5bfc\u81f4\u5404\u79cd\u5404\u6837\u7684\u6027\u80fd\u95ee\u9898\u548c\u7a33\u5b9a\u6027\u95ee\u9898\u3002\n<\/p>\n<h2>\n\tCPU\u5207\u6362\u72b6\u6001\u963b\u585e\u89e3\u51b3-\u5b58\u50a8\u7f13\u5b58\uff08Store Bufferes\uff09<br \/>\n<\/h2>\n<p>\n\t\u6bd4\u5982\u4f60\u9700\u8981\u4fee\u6539\u672c\u5730\u7f13\u5b58\u4e2d\u7684\u4e00\u6761\u4fe1\u606f\uff0c\u90a3\u4e48\u4f60\u5fc5\u987b\u5c06I\uff08\u65e0\u6548\uff09\u72b6\u6001\u901a\u77e5\u5230\u5176\u4ed6\u62e5\u6709\u8be5\u7f13\u5b58\u6570\u636e\u7684CPU\u7f13\u5b58\u4e2d\uff0c\u5e76\u4e14\u7b49\u5f85\u786e\u8ba4\u3002\u7b49\u5f85\u786e\u8ba4\u7684\u8fc7\u7a0b\u4f1a\u963b\u585e\u5904\u7406\u5668\uff0c\u8fd9\u4f1a\u964d\u4f4e\u5904\u7406\u5668\u7684\u6027\u80fd\u3002\u5e94\u4e3a\u8fd9\u4e2a\u7b49\u5f85\u8fdc\u8fdc\u6bd4\u4e00\u4e2a\u6307\u4ee4\u7684\u6267\u884c\u65f6\u95f4\u957f\u7684\u591a\u3002\n<\/p>\n<h2>\n\tStore Bufferes<br \/>\n<\/h2>\n<p>\n\t\u4e3a\u4e86\u907f\u514d\u8fd9\u79cdCPU\u8fd0\u7b97\u80fd\u529b\u7684\u6d6a\u8d39\uff0cStore Bufferes\u88ab\u5f15\u5165\u4f7f\u7528\u3002\u5904\u7406\u5668\u628a\u5b83\u60f3\u8981\u5199\u5165\u5230\u4e3b\u5b58\u7684\u503c\u5199\u5230\u7f13\u5b58\uff0c\u7136\u540e\u7ee7\u7eed\u53bb\u5904\u7406\u5176\u4ed6\u4e8b\u60c5\u3002\u5f53\u6240\u6709\u5931\u6548\u786e\u8ba4\uff08Invalidate Acknowledge\uff09\u90fd\u63a5\u6536\u5230\u65f6\uff0c\u6570\u636e\u624d\u4f1a\u6700\u7ec8\u88ab\u63d0\u4ea4\u3002<br \/>\n\t\u8fd9\u4e48\u505a\u6709\u4e24\u4e2a\u98ce\u9669\n<\/p>\n<h2>\n\tStore Bufferes\u7684\u98ce\u9669<br \/>\n<\/h2>\n<p>\n\t\u7b2c\u4e00\u3001\u5c31\u662f\u5904\u7406\u5668\u4f1a\u5c1d\u8bd5\u4ece\u5b58\u50a8\u7f13\u5b58\uff08Store buffer\uff09\u4e2d\u8bfb\u53d6\u503c\uff0c\u4f46\u5b83\u8fd8\u6ca1\u6709\u8fdb\u884c\u63d0\u4ea4\u3002\u8fd9\u4e2a\u7684\u89e3\u51b3\u65b9\u6848\u79f0\u4e3aStore Forwarding\uff0c\u5b83\u4f7f\u5f97\u52a0\u8f7d\u7684\u65f6\u5019\uff0c\u5982\u679c\u5b58\u50a8\u7f13\u5b58\u4e2d\u5b58\u5728\uff0c\u5219\u8fdb\u884c\u8fd4\u56de\u3002<br \/>\n\t\u7b2c\u4e8c\u3001\u4fdd\u5b58\u4ec0\u4e48\u65f6\u5019\u4f1a\u5b8c\u6210\uff0c\u8fd9\u4e2a\u5e76\u6ca1\u6709\u4efb\u4f55\u4fdd\u8bc1\u3002\n<\/p>\n<pre class=\"brush:java;\">\r\nvalue = 3\uff1b\r\n\/\/ \u4e1a\u4f59\u8349\uff1awww.xttblog.com\r\nvoid exeToCPUA(){\r\n  value = 10;\r\n  isFinsh = true;\r\n}\r\nvoid exeToCPUB(){\r\n  if(isFinsh){\r\n    \/\/value\u4e00\u5b9a\u7b49\u4e8e10\uff1f\uff01\r\n    assert value == 10;\r\n  }\r\n}<\/pre>\n<p>\n\t\u8bd5\u60f3\u4e00\u4e0b\u5f00\u59cb\u6267\u884c\u65f6\uff0cCPU A\u4fdd\u5b58\u7740finished\u5728E(\u72ec\u4eab)\u72b6\u6001\uff0c\u800cvalue\u5e76\u6ca1\u6709\u4fdd\u5b58\u5728\u5b83\u7684\u7f13\u5b58\u4e2d\u3002\uff08\u4f8b\u5982\uff0cInvalid\uff09\u3002\u5728\u8fd9\u79cd\u60c5\u51b5\u4e0b\uff0cvalue\u4f1a\u6bd4finished\u66f4\u8fdf\u5730\u629b\u5f03\u5b58\u50a8\u7f13\u5b58\u3002\u5b8c\u5168\u6709\u53ef\u80fdCPU B\u8bfb\u53d6finished\u7684\u503c\u4e3atrue\uff0c\u800cvalue\u7684\u503c\u4e0d\u7b49\u4e8e10\u3002\n<\/p>\n<p>\n\t\u5373isFinsh\u7684\u8d4b\u503c\u5728value\u8d4b\u503c\u4e4b\u524d\u3002\n<\/p>\n<p>\n\t\u8fd9\u79cd\u5728\u53ef\u8bc6\u522b\u7684\u884c\u4e3a\u4e2d\u53d1\u751f\u7684\u53d8\u5316\u79f0\u4e3a\u91cd\u6392\u5e8f\uff08reordings\uff09\u3002\u6ce8\u610f\uff0c\u8fd9\u4e0d\u610f\u5473\u7740\u4f60\u7684\u6307\u4ee4\u7684\u4f4d\u7f6e\u88ab\u6076\u610f\uff08\u6216\u8005\u597d\u610f\uff09\u5730\u66f4\u6539\u3002\n<\/p>\n<p>\n\t\u5b83\u53ea\u662f\u610f\u5473\u7740\u5176\u4ed6\u7684CPU\u4f1a\u8bfb\u5230\u8ddf\u7a0b\u5e8f\u4e2d\u5199\u5165\u7684\u987a\u5e8f\u4e0d\u4e00\u6837\u7684\u7ed3\u679c\u3002\n<\/p>\n<h2>\n\t\u786c\u4ef6\u5185\u5b58\u6a21\u578b<br \/>\n<\/h2>\n<p>\n\t\u6267\u884c\u5931\u6548\u4e5f\u4e0d\u662f\u4e00\u4e2a\u7b80\u5355\u7684\u64cd\u4f5c\uff0c\u5b83\u9700\u8981\u5904\u7406\u5668\u53bb\u5904\u7406\u3002\u53e6\u5916\uff0c\u5b58\u50a8\u7f13\u5b58\uff08Store Buffers\uff09\u5e76\u4e0d\u662f\u65e0\u7a77\u5927\u7684\uff0c\u6240\u4ee5\u5904\u7406\u5668\u6709\u65f6\u9700\u8981\u7b49\u5f85\u5931\u6548\u786e\u8ba4\u7684\u8fd4\u56de\u3002\u8fd9\u4e24\u4e2a\u64cd\u4f5c\u90fd\u4f1a\u4f7f\u5f97\u6027\u80fd\u5927\u5e45\u964d\u4f4e\u3002\u4e3a\u4e86\u5e94\u4ed8\u8fd9\u79cd\u60c5\u51b5\uff0c\u5f15\u5165\u4e86\u5931\u6548\u961f\u5217\u3002\u5b83\u4eec\u7684\u7ea6\u5b9a\u5982\u4e0b\uff1a\n<\/p>\n<ul>\n<li>\n\t\t\u5bf9\u4e8e\u6240\u6709\u7684\u6536\u5230\u7684Invalidate\u8bf7\u6c42\uff0cInvalidate Acknowlege\u6d88\u606f\u5fc5\u987b\u7acb\u523b\u53d1\u9001\n\t<\/li>\n<li>\n\t\tInvalidate\u5e76\u4e0d\u771f\u6b63\u6267\u884c\uff0c\u800c\u662f\u88ab\u653e\u5728\u4e00\u4e2a\u7279\u6b8a\u7684\u961f\u5217\u4e2d\uff0c\u5728\u65b9\u4fbf\u7684\u65f6\u5019\u624d\u4f1a\u53bb\u6267\u884c\u3002\n\t<\/li>\n<li>\n\t\t\u5904\u7406\u5668\u4e0d\u4f1a\u53d1\u9001\u4efb\u4f55\u6d88\u606f\u7ed9\u6240\u5904\u7406\u7684\u7f13\u5b58\u6761\u76ee\uff0c\u76f4\u5230\u5b83\u5904\u7406Invalidate\u3002\n\t<\/li>\n<\/ul>\n<p>\n\t\u5373\u4fbf\u662f\u8fd9\u6837\u5904\u7406\u5668\u5df2\u7136\u4e0d\u77e5\u9053\u4ec0\u4e48\u65f6\u5019\u4f18\u5316\u662f\u5141\u8bb8\u7684\uff0c\u800c\u4ec0\u4e48\u65f6\u5019\u5e76\u4e0d\u5141\u8bb8\u3002\u5e72\u8106\u5904\u7406\u5668\u5c06\u8fd9\u4e2a\u4efb\u52a1\u4e22\u7ed9\u4e86\u5199\u4ee3\u7801\u7684\u4eba\u3002\u8fd9\u5c31\u662f\u5185\u5b58\u5c4f\u969c\uff08Memory Barriers\uff09\u3002\n<\/p>\n<p>\n\t\u5199\u5c4f\u969c Store Memory Barrier(a.k.a. ST, SMB, smp_wmb)\u662f\u4e00\u6761\u544a\u8bc9\u5904\u7406\u5668\u5728\u6267\u884c\u8fd9\u4e4b\u540e\u7684\u6307\u4ee4\u4e4b\u524d\uff0c\u5e94\u7528\u6240\u6709\u5df2\u7ecf\u5728\u5b58\u50a8\u7f13\u5b58\uff08store buffer\uff09\u4e2d\u7684\u4fdd\u5b58\u7684\u6307\u4ee4\u3002\n<\/p>\n<p>\n\t\u8bfb\u5c4f\u969cLoad Memory Barrier (a.k.a. LD, RMB, smp_rmb)\u662f\u4e00\u6761\u544a\u8bc9\u5904\u7406\u5668\u5728\u6267\u884c\u4efb\u4f55\u7684\u52a0\u8f7d\u524d\uff0c\u5148\u5e94\u7528\u6240\u6709\u5df2\u7ecf\u5728\u5931\u6548\u961f\u5217\u4e2d\u7684\u5931\u6548\u64cd\u4f5c\u7684\u6307\u4ee4\u3002\n<\/p>\n<pre class=\"brush:java;\">\r\nvoid executedOnCpu0() {\r\n    value = 10;\r\n    \/\/\u5728\u66f4\u65b0\u6570\u636e\u4e4b\u524d\u5fc5\u987b\u5c06\u6240\u6709\u5b58\u50a8\u7f13\u5b58\uff08store buffer\uff09\u4e2d\u7684\u6307\u4ee4\u6267\u884c\u5b8c\u6bd5\u3002\r\n    storeMemoryBarrier();\r\n    finished = true;\r\n}\r\nvoid executedOnCpu1() {\r\n    while(!finished);\r\n    \/\/\u5728\u8bfb\u53d6\u4e4b\u524d\u5c06\u6240\u6709\u5931\u6548\u961f\u5217\u4e2d\u5173\u4e8e\u8be5\u6570\u636e\u7684\u6307\u4ee4\u6267\u884c\u5b8c\u6bd5\u3002\r\n    loadMemoryBarrier();\r\n    assert value == 10;\r\n}<\/pre>\n<p>\n\t\u73b0\u5728\u786e\u5b9e\u5b89\u5168\u4e86\uff0c\u5b8c\u7f8e\u65e0\u6687\uff01\n<\/p>\n<p>\n\t\u770b\u5b8c\u8fd9\u7bc7\u6587\u7ae0\uff0c\u4f60\u8fd8\u89c9\u5f97\u9020CPU\u6216\u8bbe\u8ba1CPU\u7b80\u5355\u5417\uff1f<\/p>\n<!-- <audio autoplay=\"autoplay\" height=\"100\" width=\"100\" hidden=\"true\"><source src=\"https:\/\/c.coka.la\/orAvPR.mp3\" type=\"audio\/mp3\"\/><\/audio><img decoding=\"async\" src=\"https:\/\/images.weserv.nl\/?url=https:\/\/ws3.sinaimg.cn\/large\/8fa5dcfcgy1g4em3rzar5j20ib089ae0.jpg\" alt=\"\u4e1a\u4f59\u8349\u516c\u4f17\u53f7\"\/> --><p><!-- <img decoding=\"async\" src=\"https:\/\/raw.githubusercontent.com\/xmt1139057136\/xttblog\/master\/8fa5dcfcgy1g4em3rzar5j20ib089ae0.jpg\" alt=\"\u4e1a\u4f59\u8349\u516c\u4f17\u53f7\"\/>--><img decoding=\"async\" src=\"https:\/\/saas.51autoparts.cn\/api\/admin\/sys-file\/oss\/file?fileName=84db51f8561e448f9a4fda2eff0811f9.jpg\" alt=\"\u4e1a\u4f59\u8349\u516c\u4f17\u53f7\"\/><\/p><p>\u6700\u540e\uff0c\u6b22\u8fce\u5173\u6ce8\u6211\u7684\u4e2a\u4eba\u5fae\u4fe1\u516c\u4f17\u53f7\uff1a\u4e1a\u4f59\u8349\uff08yyucao\uff09\uff01<b>\u53ef\u52a0\u4f5c\u8005\u5fae\u4fe1\u53f7\uff1a<font color=\"red\">xttblog2<\/font>\u3002\u5907\u6ce8\uff1a\u201c1\u201d\uff0c\u6dfb\u52a0\u535a\u4e3b\u5fae\u4fe1\u62c9\u4f60\u8fdb\u5fae\u4fe1\u7fa4\u3002\u5907\u6ce8\u9519\u8bef\u4e0d\u4f1a\u540c\u610f\u597d\u53cb\u7533\u8bf7\u3002<\/b>\u518d\u6b21\u611f\u8c22\u60a8\u7684\u5173\u6ce8\uff01\u540e\u7eed\u6709\u7cbe\u5f69\u5185\u5bb9\u4f1a\u7b2c\u4e00\u65f6\u95f4\u53d1\u7ed9\u60a8\uff01\u539f\u521b\u6587\u7ae0\u6295\u7a3f\u8bf7\u53d1\u9001\u81f3532009913@qq.com\u90ae\u7bb1\u3002\u5546\u52a1\u5408\u4f5c\u4e5f\u53ef\u6dfb\u52a0\u4f5c\u8005\u5fae\u4fe1\u8fdb\u884c\u8054\u7cfb\uff01<\/p><p>\u672c\u6587\u539f\u6587\u51fa\u5904\uff1a<a href=\"https:\/\/www.xttblog.com\">\u4e1a\u4f59\u8349<\/a>\uff1a &raquo; <a href=\"https:\/\/www.xttblog.com\/?p=3315\">Java\u5e76\u53d1\u4e4bCPU\u7f13\u5b58\u4e00\u81f4\u6027<\/a><\/p><!-- <div class=\"bd-reward-stl\"><button id=\"bdRewardBtn\"><span><\/span><\/button><\/div> -->","protected":false},"excerpt":{"rendered":"<p>\u53ea\u5b66\u4e60\u7f13\u5b58\u6846\u67b6\u7684\u4f7f\u7528\uff0c\u800c\u4e0d\u4e86\u89e3\u7f13\u5b58\u7684\u5e95\u5c42\u5b9e\u73b0\u903b\u8f91\uff0c\u5bf9\u4e8e\u9ad8\u7ea7\u5f00\u53d1\u6765\u8bf4\u592a\u6ca1\u7406\u60f3\u4e86\uff01\u4eca\u5929\u6211\u4eec\u6765\u804a\u804aCPU\u7684\u7f13\u5b58\u4e00\u81f4\u6027 [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5,6],"tags":[567,975,568,1147,584],"class_list":["post-3315","post","type-post","status-publish","format-standard","hentry","category-java","category-yyzt","tag-java-","tag-shiro-","tag-568","tag-1147","tag-584"],"_links":{"self":[{"href":"https:\/\/www.xttblog.com\/index.php?rest_route=\/wp\/v2\/posts\/3315","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.xttblog.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.xttblog.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.xttblog.com\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.xttblog.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=3315"}],"version-history":[{"count":1,"href":"https:\/\/www.xttblog.com\/index.php?rest_route=\/wp\/v2\/posts\/3315\/revisions"}],"predecessor-version":[{"id":3316,"href":"https:\/\/www.xttblog.com\/index.php?rest_route=\/wp\/v2\/posts\/3315\/revisions\/3316"}],"wp:attachment":[{"href":"https:\/\/www.xttblog.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=3315"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.xttblog.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=3315"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.xttblog.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=3315"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}