{"id":557,"date":"2013-11-05T15:25:48","date_gmt":"2013-11-05T07:25:48","guid":{"rendered":"http:\/\/coderbee.net\/?p=557"},"modified":"2013-12-15T16:55:52","modified_gmt":"2013-12-15T08:55:52","slug":"hotspot-%e5%9e%83%e5%9c%be%e5%9b%9e%e6%94%b6%e7%ae%97%e6%b3%95%e5%ae%9e%e7%8e%b0","status":"publish","type":"post","link":"https:\/\/coderbee.net\/index.php\/jvm\/20131105\/557","title":{"rendered":"HotSpot \u5783\u573e\u56de\u6536\u7b97\u6cd5\u5b9e\u73b0"},"content":{"rendered":"<p>\u300a\u6df1\u5165\u7406\u89e3Java\u865a\u62df\u673a\uff1aJVM\u9ad8\u7ea7\u7279\u6027\u4e0e\u6700\u4f73\u5b9e\u8df5\u300b-\u7b14\u8bb0<\/p>\n<h1>\u5783\u573e\u56de\u6536\u7b97\u6cd5<\/h1>\n<h2>\u679a\u4e3e\u6839\u7ed3\u70b9<\/h2>\n<h4>\u4e00\u81f4\u6027<\/h4>\n<p>\u5728\u53ef\u8fbe\u6027\u5206\u6790\u671f\u95f4\u6574\u4e2a\u7cfb\u7edf\u770b\u8d77\u6765\u5c31\u50cf\u88ab\u51bb\u7ed3\u5728\u67d0\u4e2a\u65f6\u95f4\u70b9\u4e0a\uff0c\u4e0d\u53ef\u4ee5\u51fa\u73b0\u5206\u6790\u8fc7\u7a0b\u4e2d\u5bf9\u8c61\u5f15\u7528\u5173\u7cfb\u8fd8\u5728\u4e0d\u65ad\u53d8\u5316\u7684\u60c5\u51b5\u3002<\/p>\n<p>\u4e00\u81f4\u6027\u8981\u6c42\u5bfc\u81f4GC\u8fdb\u884c\u65f6\u5fc5\u987b\u505c\u987f\u6240\u6709Java\u6267\u884c\u7ebf\u7a0b\u3002\uff08Stop The World\uff09<br \/>\n\u5373\u4f7f\u5728\u53f7\u79f0\u4e0d\u4f1a\u53d1\u751f\u505c\u987f\u7684CMS\u6536\u96c6\u5668\u4e2d\uff0c\u679a\u4e3e\u6839\u8282\u70b9\u65f6\u4e5f\u662f\u5fc5\u987b\u505c\u987f\u7684\u3002<\/p>\n<p>HotSpot\u4f7f\u7528\u7684\u662f\u51c6\u786e\u5f0fGC\uff0c\u5f53\u6267\u884c\u7cfb\u7edf\u505c\u987f\u4e0b\u6765\u540e\uff0c\u5e76\u4e0d\u9700\u8981\u4e00\u4e2a\u4e0d\u6f0f\u5730\u68c0\u67e5\u5b8c\u6240\u6709\u6267\u884c\u4e0a\u4e0b\u6587\u548c\u5168\u5c40\u7684\u5f15\u7528\u4f4d\u7f6e\uff0c\u8fd9\u662f\u901a\u8fc7\u4e00\u7ec4\u79f0\u4e3aOopMap\u7684\u6570\u636e\u7ed3\u6784\u6765\u8fbe\u5230\u7684\u3002<\/p>\n<p>\u5728\u7c7b\u52a0\u8f7d\u5b8c\u6210\u540e\uff0cHotSpot\u5c31\u628a\u5bf9\u8c61\u5185\u4ec0\u4e48\u504f\u79fb\u91cf\u4e0a\u662f\u4ec0\u4e48\u7c7b\u578b\u7684\u6570\u636e\u8ba1\u7b97\u51fa\u6765\uff1b\u5728JIT\u7f16\u8bd1\u8fc7\u7a0b\u4e2d\uff0c\u4e5f\u4f1a\u5728\u7279\u5b9a\u7684\u4f4d\u7f6e\u8bb0\u5f55\u4e0b\u6808\u548c\u5bc4\u5b58\u5668\u4e2d\u54ea\u4e9b\u4f4d\u7f6e\u662f\u5f15\u7528\u3002<br \/>\n<!--more--><\/p>\n<h2>\u5b89\u5168\u70b9\uff08Safe Point\uff09<\/h2>\n<p>\u7a0b\u5e8f\u53ea\u6709\u5728\u5230\u8fbe\u5b89\u5168\u70b9\u65f6\u624d\u80fd\u6682\u505c\u3002\u5b89\u5168\u70b9\u7684\u9009\u5b9a\u6807\u51c6\u662f\u201c\u662f\u5426\u5177\u6709\u8ba9\u7a0b\u5e8f\u957f\u65f6\u95f4\u6267\u884c\u7684\u7279\u5f81\u201d\u3002\u201c\u957f\u65f6\u95f4\u6267\u884c\u201d\u7684\u6700\u660e\u663e\u7279\u5f81\u5c31\u662f\u6307\u4ee4\u5e8f\u5217\u7684\u590d\u7528\uff0c\u5982\u65b9\u6cd5\u8c03\u7528\u3001\u5faa\u73af\u8df3\u8f6c\u7b49\uff0c\u5177\u6709\u8fd9\u4e9b\u529f\u80fd\u7684\u6307\u4ee4\u624d\u4f1a\u4ea7\u751f\u5b89\u5168\u70b9\u3002<\/p>\n<h3>\u8ba9\u7a0b\u5e8f\u6682\u505c\u7684\u4e24\u79cd\u65b9\u5f0f<\/h3>\n<ul>\n<li>\u62a2\u5148\u5f0f\u4e2d\u65ad\uff08Preemptive  Suspension\uff09\uff1a\u5728GC\u53d1\u751f\u65f6\uff0c\u4e3b\u52a8\u4e2d\u65ad\u6240\u6709\u7ebf\u7a0b\uff0c\u4e0d\u9700\u8981\u7ebf\u7a0b\u6267\u884c\u7684\u4ee3\u7801\u4e3b\u52a8\u914d\u5408\u3002\u51e0\u4e4e\u4e0d\u88ab\u91c7\u7528\u3002<\/p>\n<\/li>\n<li>\n<p>\u4e3b\u52a8\u5f0f\u4e2d\u65ad\uff08Voluntary  Suspension\uff09\uff1a\u8bbe\u4e00\u4e2a\u6807\u5fd7\uff0c\u5404\u4e2a\u7ebf\u7a0b\u4e3b\u52a8\u53bb\u8f6e\u8be2\u8fd9\u4e2a\u6807\u5fd7\uff0c\u9047\u5230\u4e2d\u65ad\u5219\u6682\u505c\u3002\u8f6e\u8be2\u5730\u65b9\u4e0e\u5b89\u5168\u70b9\u91cd\u5408\u3002<\/p>\n<\/li>\n<\/ul>\n<h2>\u5b89\u5168\u533a\u57df\uff08Safe Region\uff09<\/h2>\n<p>\u6307\u5728\u4e00\u6bb5\u4ee3\u7801\u7247\u6bb5\u4e2d\uff0c\u5f15\u7528\u5173\u7cfb\u4e0d\u4f1a\u53d1\u751f\u53d8\u5316\u3002\u5728\u8fd9\u4e2a\u533a\u57df\u7684\u4efb\u610f\u5730\u65b9\u5f00\u59cbGC\u90fd\u662f\u5b89\u5168\u7684\u3002<\/p>\n<p>\u7ebf\u7a0b\u6267\u884c\u5230\u5b89\u5168\u533a\u57df\u4e2d\u7684\u4ee3\u7801\u65f6\uff0c\u9996\u5148\u6807\u8bc6\u81ea\u5df1\u8fdb\u5165\u4e86\u5b89\u5168\u533a\u57df\uff1b\u5728\u79bb\u5f00\u5b89\u5168\u533a\u57df\u65f6\uff0c\u8981\u68c0\u67e5\u7cfb\u7edf\u662f\u5426\u5df2\u7ecf\u5b8c\u6210\u4e86\u679a\u4e3e\u6839\u8282\u70b9\uff08\u6216\u6574\u4e2aGC\u8fc7\u7a0b\uff09\uff0c\u5b8c\u6210\u4e86\u5c31\u7ee7\u7eed\u6267\u884c\uff0c\u5426\u5219\u5fc5\u987b\u7b49\u5f85\u76f4\u5230\u6536\u5230\u53ef\u4ee5\u5b89\u5168\u79bb\u5f00Safe Region\u7684\u4fe1\u53f7\u3002<\/p>\n<p>\u5b89\u5168\u533a\u57df\u662f\u4e3a\u4e86\u89e3\u51b3\u7ebf\u7a0bSleep\u6216Blocked\u72b6\u6001\u7684\u3002<\/p>\n<h1>\u5783\u573e\u6536\u96c6\u5668<\/h1>\n<p>\u524d\u9762\u7684\u5783\u573e\u6536\u96c6\u7b97\u6cd5\u662f\u7406\u8bba\uff0c\u5783\u573e\u6536\u96c6\u5668\u5219\u662f\u5177\u4f53\u7684\u5b9e\u73b0\u3002<\/p>\n<p>\u4e0b\u56fe\u662fHotSpot\u91cc\u7684\u6536\u96c6\u5668\uff0c\u4e2d\u95f4\u7684\u6a2a\u7ebf\u8868\u793a\u5206\u4ee3\uff0c\u6709\u8fde\u7ebf\u8868\u793a\u53ef\u4ee5\u7ec4\u5408\u4f7f\u7528\u3002<br \/>\n<img decoding=\"async\" src=\"\/\/coderbee.net\/wp-content\/uploads\/2013\/11\/HotSpot_gc.jpg\" \/><\/p>\n<h2>Serial \u6536\u96c6\u5668<\/h2>\n<p>\u662f\u4e00\u4e2a\u5355\u7ebf\u7a0b\u7684\u6536\u96c6\u5668\uff0c\u53ea\u80fd\u4f7f\u7528\u4e00\u4e2aCPU\u6216\u4e00\u6761\u7ebf\u7a0b\u53bb\u5b8c\u6210\u5783\u573e\u6536\u96c6\uff1b\u5728\u8fdb\u884c\u5783\u573e\u6536\u96c6\u65f6\uff0c\u5fc5\u987b\u6682\u505c\u6240\u6709\u5176\u4ed6\u5de5\u4f5c\u7ebf\u7a0b\uff0c\u76f4\u5230\u6536\u96c6\u5b8c\u6210\u3002<\/p>\n<p>Serial\/Serial Old \u6536\u96c6\u5668\u8fd0\u884c\u793a\u610f\u56fe\uff1a<br \/>\n<img decoding=\"async\" src=\"\/\/coderbee.net\/wp-content\/uploads\/2013\/11\/Serial_gc_runtime.jpg\" alt=\"Serial_gc_runtime\" \/><\/p>\n<p>\u7f3a\u70b9\uff1aStop-The-World\u3002<\/p>\n<p>\u4f18\u52bf\uff1a\u7b80\u5355\u3002\u5bf9\u4e8e\u4f46CPU\u7684\u60c5\u51b5\uff0c\u7531\u4e8e\u6ca1\u6709\u591a\u7ebf\u7a0b\u4ea4\u4e92\u5f00\u9500\uff0c\u53cd\u800c\u53ef\u4ee5\u66f4\u9ad8\u6548\u3002<\/p>\n<p>\u662fClient\u6a21\u5f0f\u4e0b\u9ed8\u8ba4\u7684\u65b0\u751f\u4ee3\u6536\u96c6\u5668\u3002<\/p>\n<h2>ParNew \u6536\u96c6\u5668<\/h2>\n<p>\u662fSerial\u6536\u96c6\u5668\u7684\u591a\u7ebf\u7a0b\u7248\u672c\u3002<\/p>\n<p>ParNew\/Serial Old \u6536\u96c6\u5668\u8fd0\u884c\u793a\u610f\u56fe\uff1a<br \/>\n<img decoding=\"async\" src=\"\/\/coderbee.net\/wp-content\/uploads\/2013\/11\/ParNew_gc_runtime.jpg\" alt=\"ParNew_gc_runtime\" \/><\/p>\n<h4>\u5783\u573e\u6536\u96c6\u8bed\u5883\u4e0b\u7684\u5e76\u53d1\u4e0e\u5e76\u884c\u6982\u5ff5<\/h4>\n<ul>\n<li>\u5e76\u884c\uff08Parallel\uff09\uff1a\u6307\u591a\u6761\u5783\u573e\u6536\u96c6\u7ebf\u7a0b\u5e76\u884c\u5de5\u4f5c\uff0c\u7528\u6237\u7ebf\u7a0b\u4ecd\u7136\u5904\u4e8e\u7b49\u5f85\u72b6\u6001\u3002<\/li>\n<li>\u5e76\u53d1\uff08Concurrent\uff09\uff1a\u7528\u6237\u7ebf\u7a0b\u4e0e\u5783\u573e\u6536\u96c6\u7ebf\u7a0b\u540c\u65f6\u6267\u884c\u3002<\/li>\n<\/ul>\n<h2>Parallel Scavenge \u6536\u96c6\u5668<\/h2>\n<p>\u65b0\u751f\u4ee3\u6536\u96c6\u5668\uff0c\u4f7f\u7528\u590d\u5236\u7b97\u6cd5\u3001\u5e76\u884c\u7684\u591a\u7ebf\u7a0b\u6536\u96c6\u5668\u3002<\/p>\n<p>Parallel Scavenge \u6536\u96c6\u5668\u7684\u76ee\u6807\u662f\u8fbe\u5230\u4e00\u4e2a\u53ef\u63a7\u5236\u7684\u541e\u5410\u91cf\uff08Throughput\uff09\u3002\u8fd9\u91cc\u7684\u541e\u5410\u91cf\u662f\u6307CPU\u7528\u4e8e\u8fd0\u884c\u7528\u6237\u4ee3\u7801\u7684\u65f6\u95f4\u4e0eCPU\u603b\u6d88\u8017\u65f6\u95f4\u7684\u6bd4\u503c\u3002\u4e3b\u8981\u9002\u5408\u5728\u540e\u53f0\u8fd0\u7b97\u800c\u4e0d\u9700\u8981\u592a\u591a\u4ea4\u4e92\u7684\u4efb\u52a1\u3002<\/p>\n<p>Parallel Scavenge \u6536\u96c6\u5668\u5141\u8bb8\u91c7\u7528GC\u81ea\u9002\u5e94\u7684\u8c03\u8282\u7b56\u7565\uff0c\u4e5f\u5c31\u662f\u8ba9\u865a\u62df\u673a\u6839\u636e\u6536\u96c6\u5230\u7684\u8fd0\u884c\u65f6\u6570\u636e\u81ea\u884c\u51b3\u5b9a\u5404\u4e2a\u5206\u4ee3\u7684\u5927\u5c0f\u7b49\u4e0e\u5783\u573e\u56de\u6536\u6709\u5173\u7684\u914d\u7f6e\u3002<\/p>\n<h2>Serial Old \u6536\u96c6\u5668<\/h2>\n<p>\u7528\u4e8e\u8001\u5e74\u4ee3\u7684Serial\u6536\u96c6\u5668\uff0c\u5355\u7ebf\u7a0b\uff0c\u4f7f\u7528\u201c\u6807\u8bb0-\u6574\u7406\u201d\u7b97\u6cd5\u3002<\/p>\n<p><img decoding=\"async\" src=\"\/\/coderbee.net\/wp-content\/uploads\/2013\/11\/SerialOld_gc_runtime.jpg\" alt=\"SerialOld_gc_runtime\" \/><\/p>\n<p>\u4e3b\u8981\u5728Client\u6a21\u5f0f\u4e0b\u4f7f\u7528\u3002<\/p>\n<h2>Parallel Old \u6536\u96c6\u5668<\/h2>\n<p>Parallel Scavenge\u7684\u8001\u5e74\u4ee3\u7248\u672c\uff0c\u591a\u7ebf\u7a0b\uff0c\u4f7f\u7528\u201c\u6807\u8bb0-\u6574\u7406\u201d\u7b97\u6cd5\u3002<\/p>\n<p><img decoding=\"async\" src=\"\/\/coderbee.net\/wp-content\/uploads\/2013\/11\/ParallelOld_gc_runtime.jpg\" alt=\"ParallelOld_gc_runtime\" \/><\/p>\n<h2>CMS \u6536\u96c6\u5668<\/h2>\n<p>CMS\uff08Concurrent Mark Sweep\uff09\u6536\u96c6\u5668\u662f\u4e00\u79cd\u4ee5\u83b7\u53d6\u6700\u77ed\u56de\u6536\u505c\u987f\u65f6\u95f4\u4e3a\u76ee\u6807\u7684\u6536\u96c6\u5668\u3002\u57fa\u4e8e\u201c\u6807\u8bb0-\u6e05\u9664\u201d\u7b97\u6cd5\u3002<\/p>\n<p><img decoding=\"async\" src=\"\/\/coderbee.net\/wp-content\/uploads\/2013\/11\/CMS_gc_runtime.jpg\" alt=\"CMS_gc_runtime\" \/><\/p>\n<p>\u8fd0\u4f5c\u8fc7\u7a0b\u5206\u4e3a4\u4e2a\u9636\u6bb5\uff1a<\/p>\n<ul>\n<li>\u521d\u59cb\u6807\u8bb0\uff08CMS initial mark\uff09\uff1a\u503c\u6807\u8bb0GC Roots\u80fd\u76f4\u63a5\u5173\u8054\u5230\u7684\u5bf9\u8c61\u3002<\/li>\n<li>\u5e76\u53d1\u6807\u8bb0\uff08CMS concurrent mark\uff09\uff1a\u8fdb\u884cGC RootsTracing\u7684\u8fc7\u7a0b\u3002<\/li>\n<li>\u91cd\u65b0\u6807\u8bb0\uff08CMS remark\uff09\uff1a\u4fee\u6b63\u5e76\u53d1\u6807\u8bb0\u671f\u95f4\u56e0\u7528\u6237\u7a0b\u5e8f\u7ee7\u7eed\u8fd0\u884c\u800c\u5bfc\u81f4\u6807\u8bb0\u53d1\u751f\u6539\u53d8\u7684\u90a3\u4e00\u90e8\u5206\u5bf9\u8c61\u7684\u6807\u8bb0\u3002<\/li>\n<li>\u5e76\u53d1\u6e05\u9664\uff08CMS concurrent sweep\uff09\uff1a<\/li>\n<\/ul>\n<p>\u5176\u4e2d\u6807\u8bb0\u548c\u91cd\u65b0\u6807\u8bb0\u4e24\u4e2a\u9636\u6bb5\u4ecd\u7136\u9700\u8981Stop-The-World\uff0c\u6574\u4e2a\u8fc7\u7a0b\u4e2d\u8017\u65f6\u6700\u957f\u7684\u5e76\u53d1\u6807\u8bb0\u548c\u5e76\u53d1\u6e05\u9664\u8fc7\u7a0b\u4e2d\u6536\u96c6\u5668\u90fd\u53ef\u4ee5\u548c\u7528\u6237\u7ebf\u7a0b\u4e00\u8d77\u5de5\u4f5c\u3002<\/p>\n<p>CMS\u6536\u96c6\u5668\u5bf9CPU\u8d44\u6e90\u975e\u5e38\u654f\u611f\u3002<\/p>\n<p>\u6d6e\u52a8\u5783\u573e\uff08Floating Garbage\uff09\uff1a\u7531\u4e8eCMS\u5e76\u53d1\u6e05\u7406\u9636\u6bb5\u7528\u6237\u7ebf\u7a0b\u8fd8\u5728\u8fd0\u884c\u7740\uff0c\u81ea\u7136\u4f1a\u6709\u65b0\u7684\u5783\u573e\u4ea7\u751f\uff0c\u800c\u8fd9\u4e9b\u5783\u573e\u662f\u5728\u6807\u8bb0\u8fc7\u7a0b\u4e4b\u540e\uff0cCMS\u53ea\u80fd\u5728\u4e0b\u6b21GC\u65f6\u56de\u6536\u5b83\u4eec\uff0c\u8fd9\u4e9b\u5783\u573e\u5c31\u79f0\u4e3a\u6d6e\u52a8\u5783\u573e\u3002<\/p>\n<p>CMS\u6536\u96c6\u5668\u65e0\u6cd5\u5904\u7406\u6d6e\u52a8\u5783\u573e\uff0c\u53ef\u80fd\u51fa\u73b0\u201cConcurrent Mode Failure\u201d\u5931\u8d25\u800c\u5bfc\u81f4\u53e6\u4e00\u6b21Full GC\u7684\u4ea7\u751f\u3002<\/p>\n<p>\u5728\u5783\u573e\u6536\u96c6\u9636\u6bb5\u7528\u6237\u7ebf\u7a0b\u8fd8\u5728\u8fd0\u884c\uff0c\u56e0\u6b64\u9700\u8981\u9884\u7559\u8db3\u591f\u7684\u5185\u5b58\u7ed9\u7528\u6237\u7ebf\u7a0b\u4f7f\u7528\u3002\u5982\u679c\u9884\u7559\u5185\u5b58\u4e0d\u80fd\u6ee1\u8db3\u7528\u6237\u7ebf\u7a0b\uff0c\u4f1a\u51fa\u73b0\u201cConcurrent Mode Failure\u201d\uff0c\u8fd9\u65f6\u865a\u62df\u673a\u5c06\u542f\u52a8\u4e34\u65f6\u540e\u5907\u9884\u6848\uff1a\u4e34\u65f6\u542f\u7528Serial Old\u6536\u96c6\u5668\u6765\u91cd\u65b0\u8fdb\u884c\u8001\u5e74\u4ee3\u7684\u5783\u573e\u6536\u96c6\u3002<\/p>\n<p>\u7531\u4e8eCMS\u4f7f\u7528\u7684\u662f\u6e05\u9664\u7b97\u6cd5\uff0c\u4f1a\u5bfc\u81f4\u5185\u5b58\u788e\u7247\u95ee\u9898\uff0c\u56e0\u6b64\u63d0\u4f9b\u4e86\u53c2\u6570\u7528\u4e8e\u63a7\u5236\u662f\u5426\u5728\u8fdb\u884cFullGC\u540e\u8fdb\u884c\u5185\u5b58\u6574\u7406\uff0c\u8fd8\u63d0\u4f9b\u4e86\u53c2\u6570\u7528\u4e8e\u63a7\u5236\u5728\u591a\u5c11\u6b21FullGC\u65f6\u624d\u8fdb\u884c\u5185\u5b58\u6574\u7406\u3002\u5185\u5b58\u6574\u7406\u662f\u4e0d\u80fd\u5e76\u53d1\u7684\uff0c\u4e5f\u5c31\u662f\u8981\u6682\u505c\u6240\u6709\u7528\u6237\u7ebf\u7a0b\u3002<\/p>\n<h2>G1 \u6536\u96c6\u5668<\/h2>\n<p>G1\uff08Garbage First\uff09\uff1a\u662f\u4e00\u6b3e\u9762\u5411\u670d\u52a1\u7aef\u5e94\u7528\u7684\u5783\u573e\u6536\u96c6\u5668\uff0c\u7528\u4e8e\u66ff\u6362CMS\u6536\u96c6\u5668\u3002<\/p>\n<p><img decoding=\"async\" src=\"\/\/coderbee.net\/wp-content\/uploads\/2013\/11\/G1_gc_runtime.jpg\" alt=\"G1_gc_runtime\" \/><\/p>\n<p>G1\u5c06\u6574\u4e2aJava\u5806\u5212\u5206\u4e3a\u5927\u5c0f\u76f8\u7b49\u7684\u72ec\u7acb\u533a\u57df\uff08Region\uff09\uff1b\u65b0\u751f\u4ee3\u548c\u8001\u5e74\u4ee3\u4e0d\u518d\u662f\u7269\u7406\u9694\u79bb\u7684\uff0c\u90fd\u7531\u4e00\u7ec4\u4e0d\u8fde\u7eed\u7684Region\u7ec4\u6210\u3002<\/p>\n<p>G1\u7684\u7279\u70b9\uff1a<\/p>\n<ul>\n<li>\u5e76\u884c\u4e0e\u5e76\u53d1\uff1a\u5145\u5206\u5229\u7528\u591aCPU\u7f29\u77edStop-The-World\u505c\u987f\u65f6\u95f4\uff0c\u5728\u6536\u96c6\u8fc7\u7a0b\u4e2d\u7528\u5e76\u53d1\u7684\u65b9\u5f0f\u8ba9Java\u7ebf\u7a0b\u7ee7\u7eed\u6267\u884c\u3002<\/li>\n<li>\u5206\u4ee3\u6536\u96c6\uff1a\u4ecd\u7136\u6709\u5206\u4ee3\u7684\u6982\u5ff5\uff0c\u4e0d\u9700\u8981\u5176\u4ed6\u6536\u96c6\u5668\u914d\u5408\uff0c\u72ec\u7acb\u7ba1\u7406\u6574\u4e2aGC\u5806\u3002<\/li>\n<li>\u7a7a\u95f4\u6574\u5408\uff1a\u4ece\u6574\u4f53\u770b\uff0c\u662f\u57fa\u4e8e\u201c\u6807\u8bb0-\u6574\u7406\u201d\u7b97\u6cd5\u5b9e\u73b0\u7684\uff0c\u4ece\u5c40\u90e8\uff08\u4e24\u4e2aRegion\u4e4b\u95f4\uff09\u770b\u662f\u57fa\u4e8e\u201c\u590d\u5236\u201d\u7b97\u6cd5\u7684\u3002\u5728\u8fd0\u884c\u671f\u95f4\u4e0d\u4f1a\u4ea7\u751f\u5185\u5b58\u788e\u7247\u3002<\/li>\n<li>\u53ef\u9884\u6d4b\u7684\u505c\u987f\uff1aG1\u8ddf\u8e2a\u5404\u4e2aRegion\u91cc\u5783\u573e\u5806\u79ef\u503c\u7684\u4ef7\u503c\u5927\u5c0f\uff0c\u7ef4\u62a4\u4e00\u4e2a\u4f18\u5148\u7ea7\u961f\u5217\uff0c\u6bcf\u6b21\u6839\u636e\u5141\u8bb8\u7684\u65f6\u95f4\uff0c\u4f18\u5148\u56de\u6536\u4ef7\u503c\u6700\u5927\u7684Region\u3002\uff08\u8fd9\u4e5f\u662fGarbage First\u7684\u7531\u6765\uff09<\/li>\n<\/ul>\n<p>Region\u4e4b\u95f4\u7684\u5bf9\u8c61\u5f15\u7528\u4ee5\u53ca\u5176\u4ed6\u6536\u96c6\u5668\u4e2d\u7684\u65b0\u751f\u4ee3\u4e0e\u8001\u5e74\u4ee3\u4e4b\u95f4\u7684\u5bf9\u8c61\u5f15\u7528\uff0c\u865a\u62df\u673a\u90fd\u662f\u4f7f\u7528Remembered Set\u6765\u907f\u514d\u5168\u5806\u626b\u63cf\u7684\u3002<\/p>\n<p>G1\u4e2d\u6bcf\u4e2aRegion\u90fd\u6709\u4e00\u4e2a\u4e0e\u4e4b\u5bf9\u5e94\u7684Remembered Set\uff0c\u865a\u62df\u673a\u53d1\u73b0\u7a0b\u5e8f\u5bf9\u5f15\u7528\u7c7b\u578b\u7684\u6570\u636e\u8fdb\u884c\u5199\u64cd\u4f5c\u65f6\uff0c\u4f1a\u4ea7\u751f\u4e00\u4e2aWrite Barrier\u6682\u65f6\u4e2d\u65ad\u5199\u64cd\u4f5c\uff0c\u68c0\u67e5\u5f15\u7528\u7684\u5bf9\u8c61\u662f\u5426\u5904\u4e8e\u4e0d\u540c\u7684Region\u4e2d\uff08\u5728\u5176\u4ed6\u6536\u96c6\u5668\u4e2d\u5c31\u662f\u68c0\u67e5\u662f\u5426\u8001\u5e74\u4ee3\u4e2d\u7684\u5bf9\u8c61\u5f15\u7528\u4e86\u65b0\u751f\u4ee3\u4e2d\u5bf9\u8c61\uff09\uff0c\u5982\u679c\u662f\uff0c\u901a\u8fc7CardTable\u628a\u76f8\u5173\u5f15\u7528\u4fe1\u606f\u8bb0\u5f55\u5230<strong>\u88ab\u5f15\u7528\u5bf9\u8c61<\/strong>\u6240\u5c5e\u7684Region\u7684Remembered Set\u4e2d\u3002\u8fdb\u884c\u5185\u5b58\u56de\u6536\u65f6\uff0c\u5728GC\u6839\u8282\u70b9\u7684\u679a\u4e3e\u8303\u56f4\u4e2d\u52a0\u5165Remembered Set\u5373\u53ef\u4fdd\u8bc1\u4e0d\u5bf9\u5168\u5806\u626b\u63cf\u4e5f\u4e0d\u4f1a\u6709\u9057\u6f0f\u3002<\/p>\n<p>G1\u5783\u573e\u56de\u6536\u4e3b\u8981\u67094\u4e2a\u9636\u6bb5\uff1a<\/p>\n<ul>\n<li>\u521d\u59cb\u6807\u8bb0\uff1a\u53ea\u6807\u8bb0GC Roots\u80fd\u76f4\u63a5\u5173\u8054\u5230\u7684\u5bf9\u8c61\uff0c\u5e76\u4e14\u4fee\u6539TAMS\uff08Next Top at Mark Start\uff09\u503c\uff0c\u8ba9\u4e0b\u4e00\u9636\u6bb5\u7528\u6237\u7a0b\u5e8f\u5e76\u53d1\u8fd0\u884c\u65f6\uff0c\u80fd\u5728\u6b63\u786e\u53ef\u7528\u7684Region\u4e2d\u521b\u5efa\u65b0\u5bf9\u8c61\u3002\u6b64\u9636\u6bb5\u9700\u8981\u6682\u505c\u7528\u6237\u7ebf\u7a0b\u3002<\/li>\n<li>\u5e76\u53d1\u6807\u8bb0\uff1a\u4eceGC Roots\u5f00\u59cb\u5bf9\u5806\u4e2d\u5bf9\u8c61\u8fdb\u884c\u53ef\u8fbe\u6027\u5206\u6790\uff0c\u627e\u51fa\u5b58\u6d3b\u5bf9\u8c61\uff1b\u8017\u65f6\u8f83\u957f\uff0c\u53ef\u4e0e\u7528\u6237\u7ebf\u7a0b\u5e76\u53d1\u6267\u884c\u3002<\/li>\n<li>\u6700\u7ec8\u6807\u8bb0\uff1a\u4fee\u6b63\u5728\u5e76\u53d1\u6807\u8bb0\u671f\u95f4\u6709\u53d8\u52a8\u7684\u6807\u8bb0\u8bb0\u5f55\u3002<\/li>\n<li>\u5237\u9009\u56de\u6536\uff1a\u5bf9\u5404\u4e2aRegion\u7684\u56de\u6536\u4ef7\u503c\u548c\u6210\u672c\u8fdb\u884c\u6392\u5e8f\uff0c\u6839\u636e\u7528\u6237\u671f\u671b\u7684GC\u505c\u987f\u65f6\u95f4\u5236\u5b9a\u56de\u6536\u8ba1\u5212\uff0c\u8fdb\u884c\u5783\u573e\u56de\u6536\u3002<\/li>\n<\/ul>\n<h1>\u5185\u5b58\u5206\u914d\u4e0e\u56de\u6536\u89c4\u5219<\/h1>\n<p>\u5185\u5b58\u5206\u914d\u4e0e\u56de\u6536\u89c4\u5219\u7531\u5783\u573e\u56de\u6536\u5668\u548c\u5185\u5b58\u6709\u5173\u53c2\u6570\u51b3\u5b9a\uff0c\u4e0d\u662f\u56fa\u5b9a\u7684\u3002<\/p>\n<p>\u4e24\u4e2a\u6982\u5ff5\uff1a<\/p>\n<ul>\n<li><strong>MinorGC\uff0c\u6b21\u6536\u96c6<\/strong>\uff1a\u5728\u65b0\u751f\u4ee3\u53d1\u751f\u7684\u5783\u573e\u6536\u96c6\uff0c\u901f\u5ea6\u5feb\uff0c\u53d1\u751f\u9891\u7e41\u3002<\/li>\n<li><strong>FullGC\uff0cMajorGC\uff0c\u4e3b\u6536\u96c6<\/strong>\uff1a\u53d1\u751f\u5728\u5e74\u8001\u4ee3\u7684\u5783\u573e\u6536\u96c6\u3002\u4e00\u822c\u4f34\u968f\u4e00\u6b21MinorGC\u3002<\/li>\n<\/ul>\n<p>\u4e00\u822c\u7684\u89c4\u5219\uff1a<\/p>\n<ul>\n<li>\n<p><strong>\u5bf9\u8c61\u4f18\u5148\u5728Eden\u5206\u914d<\/strong>\u3002\u5f53Eden\u6ca1\u6709\u8db3\u591f\u7684\u7a7a\u95f4\u65f6\uff0c\u865a\u62df\u673a\u5c06\u53d1\u8d77\u4e00\u6b21MinorGC\u3002<\/p>\n<\/li>\n<li>\n<p><strong>\u5927\u5bf9\u8c61\u76f4\u63a5\u8fdb\u5165\u8001\u5e74\u4ee3<\/strong>\u3002\u5927\u5bf9\u8c61\u662f\u6307\u9700\u8981\u8fde\u7eed\u5185\u5b58\u7a7a\u95f4\u7684Java\u5bf9\u8c61\u3002\u76ee\u7684\u662f\u907f\u514d\u5728Eden\u533a\u53ca\u4e24\u4e2aSurvivor\u533a\u4e4b\u95f4\u5927\u91cf\u7684\u5185\u5b58\u590d\u5236\uff08\u65b0\u751f\u4ee3\u91c7\u7528\u590d\u5236\u7b97\u6cd5\u6536\u96c6\u5185\u5b58\uff09\u3002<\/p>\n<\/li>\n<li>\n<p><strong>\u957f\u671f\u5b58\u6d3b\u5bf9\u8c61\u5c06\u8fdb\u5165\u8001\u5e74\u4ee3<\/strong>\u3002\u865a\u62df\u673a\u7ed9\u6bcf\u4e2a\u5bf9\u8c61\u5b9a\u4e49\u4e00\u4e2a\u5bf9\u8c61\u5e74\u9f84\u8ba1\u6570\u5668\uff0c\u5982\u679c\u5bf9\u8c61\u5728Eden\u51fa\u751f\u5e76\u7ecf\u8fc7\u4e00\u6b21Minor GC\u540e\u4ecd\u7136\u5b58\u6d3b\uff0c\u5e76\u4e14\u80fd\u591f\u88abSurvivor\u5bb9\u7eb3\uff0c\u5c06\u88ab\u79fb\u52a8\u5230Survivor\u7a7a\u95f4\uff0c\u5e76\u4e14\u5bf9\u8c61\u5e74\u9f84\u8bbe\u4e3a1\u3002\u5bf9\u8c61\u5728Survivor\u533a\u4e2d\u6bcf\u201c\u71ac\u8fc7\u201d\u4e00\u6b21MinorGC\uff0c\u5e74\u9f84\u5c31\u52a01\uff0c\u8fbe\u5230\u67d0\u4e2a\u9600\u503c\u5c31\u664b\u5347\u5230\u5e74\u8001\u4ee3\u3002<\/p>\n<\/li>\n<li>\n<p><strong>\u7a7a\u95f4\u5206\u914d\u62c5\u4fdd<\/strong>\u3002\u5728\u53d1\u751fMinor GC\u4e4b\u524d\uff0c\u865a\u62df\u673a\u4f1a\u5148\u68c0\u67e5\u5e74\u8001\u4ee3\u6700\u5927\u53ef\u7528\u7684\u8fde\u7eed\u7a7a\u95f4\u7b97\u6cd5\u5927\u4e8e\u65b0\u751f\u4ee3\u6240\u6709\u5bf9\u8c61\u603b\u7a7a\u95f4\uff0c\u5982\u679c\u662f\uff0c\u90a3\u4e48Minor GC\u53ef\u4ee5\u786e\u4fdd\u662f\u5b89\u5168\u7684\u3002\u5982\u679c\u5426\uff0c\u865a\u62df\u673a\u4f1a\u67e5\u770bHandlePromotionFailure\u8bbe\u7f6e\u662f\u5426\u5141\u8bb8\u62c5\u4fdd\u5931\u8d25\u3002\u5982\u679c\u5141\u8bb8\u7ee7\u7eed\u68c0\u67e5\u8001\u5e74\u4ee3\u6700\u5927\u53ef\u7528\u7684\u8fde\u7eed\u7a7a\u95f4\u662f\u5426\u5927\u4e8e\u5386\u6b21\u664b\u5347\u5230\u8001\u5e74\u4ee3\u5bf9\u8c61\u7684\u5e73\u5747\u5927\u5c0f\uff0c\u5982\u679c\u5927\u4e8e\uff0c\u5c06\u5c1d\u8bd5\u8fdb\u884c\u4e00\u6b21Minor GC\uff0c\u8fd9\u662f\u6709\u98ce\u9669\u7684\uff08\u5b58\u6d3b\u5bf9\u8c61\u5360\u7528\u7684\u5185\u5b58\u5927\u4e8e\u5e73\u5747\u5927\u5c0f\uff0c\u5c06\u5bfc\u81f4HandlePromotionFailure\u5931\u8d25\uff0c\u91cd\u65b0\u53d1\u8d77\u4e00\u6b21Full GC\uff09\uff1b\u5982\u679c\u5c0f\u4e8e\u6216\u8005HandlePromotionFailure\u8bbe\u7f6e\u4e0d\u5141\u8bb8\u5192\u9669\uff0c\u5c06\u6539\u4e3aFull GC\u3002<\/p>\n<\/li>\n<\/ul>\n<hr\/>\n<p>\u6b22\u8fce\u5173\u6ce8\u6211\u7684\u5fae\u4fe1\u516c\u4f17\u53f7: <strong>coderbee\u7b14\u8bb0<\/strong>\uff0c\u53ef\u4ee5\u66f4\u53ca\u65f6\u56de\u590d\u4f60\u7684\u8ba8\u8bba\u3002<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" width=\"258\" height=\"258\" src=\"https:\/\/coderbee.net\/wp-content\/uploads\/2019\/01\/coderbee-note.jpg\" class=\"alignnone size-full wp-image-1707\"><\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u300a\u6df1\u5165\u7406\u89e3Java\u865a\u62df\u673a\uff1aJVM\u9ad8\u7ea7\u7279\u6027\u4e0e\u6700\u4f73\u5b9e\u8df5\u300b-\u7b14\u8bb0 \u5783\u573e\u56de\u6536\u7b97\u6cd5 \u679a\u4e3e\u6839 &hellip; <a href=\"https:\/\/coderbee.net\/index.php\/jvm\/20131105\/557\">\u7ee7\u7eed\u9605\u8bfb <span 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