<\/p>\n
\u9996\u5148\u975e\u5e38\u611f\u8c22\u9605\u8bfb\u6211\u6587\u7ae0\u7684\u670b\u53cb\uff0c\u540c\u65f6\u4e5f\u7279\u522b\u611f\u8c22\u9605\u8bfb\u7684\u8fc7\u7a0b\u4e2d\u5e26\u7740\u81ea\u5df1\u7684\u601d\u8003\uff0c\u63d0\u51fa\u6709\u4ef7\u503c\u7684\u95ee\u9898\u7684\u670b\u53cb\uff0c\u8fd9\u5bf9\u6211\u800c\u8a00\u662f\u4e00\u79cd\u6b63\u53cd\u9988\u3002<\/p>\n
\u6211\u5f53\u65f6\u5199\u7684\u65f6\u5019\u786e\u5b9e\u6ca1\u6709\u60f3\u5230\u8fd9\u4e2a\u95ee\u9898\uff0c\u6240\u4ee5\u5f53\u7a81\u7136\u95ee\u8d77\u7684\u65f6\u5019\u6211\u5927\u6982\u77e5\u9053\u539f\u56e0\uff0c\u7531\u4e8e\u672a\u505a\u9a8c\u8bc1\uff0c\u6240\u4ee5\u4e5f\u4e0d\u6562\u8d38\u7136\u56de\u7b54\u3002<\/p>\n
\u4e8e\u662f\u6211\u5bfb\u627e\u4e86\u8fd9\u4e2a\u95ee\u9898\u7684\u7b54\u6848\uff0c\u6240\u4ee5\u5148\u8bf4\u7ed3\u8bba\uff1a<\/p>\n
\u5c31\u662f\u548c JIT \u7f16\u8bd1\u5668\u6709\u5173\u3002\u7531\u4e8e\u5faa\u73af\u4f53\u4e2d\u7684\u4ee3\u7801\u88ab\u5224\u5b9a\u4e3a\u70ed\u70b9\u4ee3\u7801\uff0c\u6240\u4ee5\u7ecf\u8fc7 JIT \u7f16\u8bd1\u540e getAndAdd \u65b9\u6cd5\u7684\u8fdb\u5165\u5b89\u5168\u70b9\u7684\u673a\u4f1a\u88ab\u4f18\u5316\u6389\u4e86\uff0c\u6240\u4ee5\u7ebf\u7a0b\u4e0d\u80fd\u5728\u5faa\u73af\u4f53\u80fd\u8fdb\u5165\u5b89\u5168\u70b9\u3002<\/p><\/blockquote>\n
\u662f\u7684\uff0c\u88ab\u4f18\u5316\u4e86\uff0c\u6211\u6253\u8fd9\u4e2a\u8bcd\u90fd\u611f\u89c9\u5f88\u6b8b\u5fcd\u3002<\/p>\n
<\/p>\n
\u63a5\u4e0b\u6765\u6211\u51c6\u5907\u5199\u4e2a\u201c\u4e0b\u96c6\u201d\uff0c\u544a\u8bc9\u4f60\u6211\u662f\u600e\u4e48\u5f97\u5230\u8fd9\u4e2a\u7ed3\u8bba\u7684\u3002\u4f46\u662f\u4e3a\u4e86\u8ba9\u4f60\u4e1d\u6ed1\u5165\u620f\uff0c\u6211\u5148\u5e26\u4f60\u7b80\u5355\u7684\u56de\u987e\u4e00\u4e0b\u201c\u4e0a\u96c6\u201d\u3002<\/p>\n
\u53e6\u5916\uff0c\u5148\u628a\u8bdd\u8bf4\u5728\u524d\u9762\uff0c\u8fd9\u77e5\u8bc6\u70b9\u5427\uff0c\u5c5e\u4e8e\u53ef\u80fd\u4e00\u8f88\u5b50\u90fd\u9047\u4e0d\u5230\u7684\u90a3\u79cd\u3002\u56e0\u6b64\u6211\u628a\u5b83\u5212\u5206\u5230\u6211\u5199\u7684\u201c\u6ca1\u6709\u5375\u7528\u7cfb\u5217\u201d\uff0c\u770b\u7740\u4e5f\u5c31\u56fe\u4e00\u4e50\u3002<\/strong><\/p>\n
\u597d\u4e86\uff0c\u5728\u4e4b\u524d\u7684\u90a3\u7bc7\u6587\u7ae0\u4e2d\uff0c\u6211\u7ed9\u51fa\u4e86\u8fd9\u6837\u7684\u4e00\u4e2a\u6d4b\u8bd5\u7528\u4f8b\uff1a<\/p>\n
public class MainTest {\n\n public static AtomicInteger num = new AtomicInteger(0);\n\n public static void main(String[] args) throws InterruptedException {\n Runnable runnable=()->{\n for (int i = 0; i < 1000000000; i++) {\n num.getAndAdd(1);\n }\n System.out.println(Thread.currentThread().getName()+"\u6267\u884c\u7ed3\u675f!");\n };\n\n Thread t1 = new Thread(runnable);\n Thread t2 = new Thread(runnable);\n t1.start();\n t2.start();\n Thread.sleep(1000);\n System.out.println("num = " + num);\n }\n}<\/code><\/pre>\n\u6309\u7167\u4ee3\u7801\u6765\u770b\uff0c\u4e3b\u7ebf\u7a0b\u4f11\u7720 1000ms \u540e\u5c31\u4f1a\u8f93\u51fa\u7ed3\u679c\uff0c\u4f46\u662f\u5b9e\u9645\u60c5\u51b5\u5374\u662f\u4e3b\u7ebf\u7a0b\u4e00\u76f4\u5728\u7b49\u5f85 t1,t2 \u6267\u884c\u7ed3\u675f\u624d\u7ee7\u7eed\u6267\u884c\u3002<\/p>\n
\u8fd0\u884c\u7ed3\u679c\u662f\u8fd9\u6837\u7684\uff1a<\/p>\n
<\/p>\n
\u5176\u5b9e\u6211\u5728\u8fd9\u91cc\u57cb\u4e86\u201c\u5f69\u86cb\u201d\uff0c\u8fd9\u4e2a\u4ee3\u7801\u867d\u7136\u4f60\u76f4\u63a5\u7c98\u8d34\u8fc7\u53bb\u5c31\u80fd\u8dd1\uff0c\u4f46\u662f\u5982\u679c\u4f60\u7684 JDK \u7248\u672c\u9ad8\u4e8e 10\uff0c\u90a3\u4e48\u8fd0\u884c\u7ed3\u679c\u5c31\u548c\u6211\u524d\u9762\u8bf4\u7684\u4e0d\u4e00\u6837\u4e86\u3002<\/p>\n
\u4ece\u7ed3\u679c\u6765\u770b\uff0c\u8fd8\u662f\u6709\u4e0d\u5c11\u4eba\u6316\u6398\u5230\u4e86\u8fd9\u4e2a\u201c\u5f69\u86cb\u201d\uff1a<\/p>\n
<\/p>\n
\u6240\u4ee5\u770b\u6587\u7ae0\u7684\u65f6\u5019\uff0c\u6709\u673a\u4f1a\u81ea\u5df1\u4eb2\u81ea\u9a8c\u8bc1\u4e00\u4e0b\uff0c\u8bf4\u4e0d\u5b9a\u4f1a\u6709\u610f\u5916\u6536\u83b7\u7684\u3002<\/p>\n
\u9488\u5bf9\u7a0b\u5e8f\u8868\u73b0\u548c\u9884\u671f\u4e0d\u4e00\u81f4\u7684\u95ee\u9898\uff0c\u7b2c\u4e00\u4e2a\u89e3\u51b3\u65b9\u6848\u662f\u8fd9\u6837\u7684\uff1a<\/p>\n
<\/p>\n
\u628a int \u4fee\u6539\u4e3a long \u5c31\u641e\u5b9a\u4e86\u3002\u81f3\u4e8e\u4e3a\u4ec0\u4e48\uff0c\u4e4b\u524d\u7684\u6587\u7ae0\u4e2d\u5df2\u7ecf\u8bf4\u660e\u4e86\uff0c\u8fd9\u91cc\u5c31\u4e0d\u8d58\u8ff0\u4e86\u3002<\/p>\n
\u5173\u952e\u7684\u662f\u4e0b\u9762\u8fd9\u4e2a\u89e3\u51b3\u65b9\u6848\uff0c\u6240\u6709\u7684\u4e89\u8bae\u90fd\u56f4\u7ed5\u7740\u5b83\u5c55\u5f00\u3002<\/p>\n
\u53d7\u5230 RocketMQ \u6e90\u7801\u7684\u542f\u793a\uff0c\u6211\u628a\u4ee3\u7801\u4fee\u6539\u4e3a\u4e86\u8fd9\u6837\uff1a<\/p>\n
<\/p>\n
\u4ece\u8fd0\u884c\u7ed3\u679c\u4e0a\u6765\u770b \uff0c\u5373\u4f7f for \u5faa\u73af\u7684\u5bf9\u8c61\u662f int \u7c7b\u578b\uff0c\u4e5f\u53ef\u4ee5\u6309\u7167\u9884\u671f\u6267\u884c\u3002<\/p>\n
\u4e3a\u4ec0\u4e48\u5462\uff1f<\/p>\n
\u56e0\u4e3a\u5728\u4e0a\u96c6\u4e2d\u5173\u4e8e sleep \u6211\u901a\u8fc7\u67e5\u9605\u8d44\u6599\u5f97\u51fa\u4e86\u8fd9\u6837\u7684\u4e24\u4e2a\u7ed3\u8bba\uff1a<\/p>\n
\n
- 1.\u6b63\u5728\u6267\u884c native \u51fd\u6570\u7684\u7ebf\u7a0b\u53ef\u4ee5\u770b\u4f5c\u201c\u5df2\u7ecf\u8fdb\u5165\u4e86safepoint\u201d\u3002<\/li>\n
- 2.\u7531\u4e8e sleep \u65b9\u6cd5\u662f native \u7684\uff0c\u6240\u4ee5\u8c03\u7528 sleep \u65b9\u6cd5\u7684\u7ebf\u7a0b\u4f1a\u8fdb\u5165 Safepoint\u3002<\/li>\n<\/ul>\n
\u8bba\u70b9\u6e05\u6670\u3001\u8bba\u636e\u5408\u7406\u3001\u63a8\u7406\u5b8c\u7f8e\u3001\u4e8b\u5b9e\u6e05\u695a\uff0c\u6240\u4ee5\u4e0a\u96c6\u6f14\u5230\u8fd9\u91cc\u5c31\u7ed3\u675f\u4e86…<\/p>\n
<\/p>\n
\u76f4\u5230\uff0c\u6709\u5f88\u591a\u670b\u53cb\u95ee\u51fa\u4e86\u8fd9\u4e2a\u95ee\u9898\uff1a<\/p>\n
\u53ef\u662f num.getAndAdd \u5e95\u5c42\u4e5f\u662f native \u65b9\u6cd5\u8c03\u7528\u554a\uff1f<\/p><\/blockquote>\n
<\/p>\n
\u5bf9\u554a\uff0c\u548c sleep \u65b9\u6cd5\u4e00\u6837\uff0c\u8fd9\u4e5f\u662f native \u65b9\u6cd5\u8c03\u7528\u554a\uff0c\u5b8c\u5168\u7b26\u5408\u524d\u9762\u7684\u7ed3\u8bba\u554a\uff0c\u5b83\u4e3a\u4ec0\u4e48\u4e0d\u8fdb\u5165\u5b89\u5168\u70b9\u5462\uff0c\u4e3a\u4ec0\u4e48\u8981\u641e\u5dee\u522b\u5bf9\u5f85\u5462\uff1f<\/p>\n
<\/p>\n
\u5927\u80c6\u5047\u8bbe<\/h2>\n
\u770b\u5230\u95ee\u9898\u7684\u65f6\u5019\uff0c\u6211\u7684\u7b2c\u4e00\u53cd\u5e94\u5c31\u662f\u5148\u628a\u9505\u7529\u7ed9 JIT \u5427\uff0c\u6bd5\u7adf\u9664\u4e86\u5b83\uff0c\u5176\u4ed6\u7684\u6211\u4e5f\u5b9e\u5728\u60f3\uff08\u4e0d\uff09\u4e0d\uff08\u4e86\uff09\u5230\uff08\u89e3\uff09\u3002<\/p>\n
\u4e3a\u4ec0\u4e48\u6211\u4f1a\u76f4\u63a5\u60f3\u5230 JIT \u5462\uff1f<\/p>\n
\u56e0\u4e3a\u5faa\u73af\u4e2d\u7684\u8fd9\u4e00\u884c\u7684\u4ee3\u7801\u5c5e\u4e8e\u5178\u578b\u7684\u70ed\u70b9\u4ee3\u7801\uff1a<\/p>\n
num.getAndAdd(1);<\/p><\/blockquote>\n
\u5f15\u7528\u300a\u6df1\u5165\u7406\u89e3JVM\u865a\u62df\u673a\u300b\u91cc\u9762\u7684\u63cf\u8ff0\uff0c\u70ed\u70b9\u4ee3\u7801\uff0c\u4e3b\u8981\u662f\u5206\u4e3a\u4e24\u7c7b\uff1a<\/p>\n
\n
- \u88ab\u591a\u6b21\u8c03\u7528\u7684\u65b9\u6cd5\u3002<\/li>\n
- \u88ab\u591a\u6b21\u6267\u884c\u7684\u5faa\u73af\u4f53\u3002<\/li>\n<\/ul>\n
\u524d\u8005\u5f88\u597d\u7406\u89e3\uff0c\u4e00\u4e2a\u65b9\u6cd5\u88ab\u8c03\u7528\u5f97\u591a\u4e86\uff0c\u65b9\u6cd5\u4f53\u5185\u4ee3\u7801\u6267\u884c\u7684\u6b21\u6570\u81ea\u7136\u5c31\u591a\uff0c\u5b83\u6210\u4e3a\u201c\u70ed\u70b9\u4ee3\u7801\u201d\u662f\u7406\u6240\u5f53\u7136\u7684\u3002<\/p>\n
\u800c\u540e\u8005\u5219\u662f\u4e3a\u4e86\u89e3\u51b3\u5f53\u4e00\u4e2a\u65b9\u6cd5\u53ea\u88ab\u8c03\u7528\u8fc7\u4e00\u6b21\u6216\u5c11\u91cf\u7684\u51e0\u6b21\uff0c\u4f46\u662f\u65b9\u6cd5\u4f53\u5185\u90e8\u5b58\u5728\u5faa\u73af\u6b21\u6570\u8f83\u591a\u7684\u5faa\u73af\u4f53\uff0c\u8fd9\u6837\u5faa\u73af\u4f53\u7684\u4ee3\u7801\u4e5f\u88ab\u91cd\u590d\u6267\u884c\u591a\u6b21\uff0c\u56e0\u6b64\u8fd9\u4e9b\u4ee3\u7801\u4e5f\u5e94\u8be5\u8ba4\u4e3a\u662f\u201c\u70ed\u70b9\u4ee3\u7801\u201d\u3002\u5f88\u660e\u663e\uff0c\u6211\u4eec\u7684\u793a\u4f8b\u4ee3\u7801\u5c31\u5c5e\u4e8e\u8fd9\u79cd\u60c5\u51b5\u3002<\/p>\n
\u5728\u6211\u4eec\u7684\u793a\u4f8b\u4ee3\u7801\u4e2d\uff0c\u5faa\u73af\u4f53\u89e6\u53d1\u4e86\u70ed\u70b9\u4ee3\u7801\u7684\u7f16\u8bd1\u52a8\u4f5c\uff0c\u800c\u5faa\u73af\u4f53\u53ea\u662f\u65b9\u6cd5\u7684\u4e00\u90e8\u5206\uff0c\u4f46\u7f16\u8bd1\u5668\u4f9d\u7136\u5fc5\u987b\u4ee5\u6574\u4e2a\u65b9\u6cd5\u4f5c\u4e3a\u7f16\u8bd1\u5bf9\u8c61\u3002<\/p>\n
\u56e0\u4e3a\u7f16\u8bd1\u7684\u76ee\u6807\u5bf9\u8c61\u90fd\u662f\u6574\u4e2a\u65b9\u6cd5\u4f53\uff0c\u4e0d\u4f1a\u662f\u5355\u72ec\u7684\u5faa\u73af\u4f53\u3002<\/p>\n
\u65e2\u7136\u4e24\u79cd\u7c7b\u578b\u90fd\u662f\u201c\u6574\u4e2a\u65b9\u6cd5\u4f53\u201d\uff0c\u90a3\u4e48\u533a\u522b\u5728\u4e8e\u4ec0\u4e48\u5730\u65b9\uff1f<\/p>\n
\u533a\u522b\u5c31\u5728\u4e8e\u6267\u884c\u5165\u53e3\uff08\u4ece\u65b9\u6cd5\u7b2c\u51e0\u6761\u5b57\u8282\u7801\u6307\u4ee4\u5f00\u59cb\u6267\u884c\uff09\u4f1a\u7a0d\u6709\u4e0d\u540c\uff0c\u7f16\u8bd1\u65f6\u4f1a\u4f20\u5165\u6267\u884c\u5165\u53e3\u70b9\u5b57\u8282\u7801\u5e8f\u53f7\uff08Byte Code Index\uff0cBCI\uff09\u3002<\/p>\n
\u8fd9\u79cd\u7f16\u8bd1\u65b9\u5f0f\u56e0\u4e3a\u7f16\u8bd1\u53d1\u751f\u5728\u65b9\u6cd5\u6267\u884c\u7684\u8fc7\u7a0b\u4e2d\uff0c\u56e0\u6b64\u88ab\u5f88\u5f62\u8c61\u5730\u79f0\u4e3a\u201c\u6808\u4e0a\u66ff\u6362\u201d\uff08On Stack Replacement\uff0cOSR\uff09\uff0c\u5373\u65b9\u6cd5\u7684\u6808\u5e27\u8fd8\u5728\u6808\u4e0a\uff0c\u65b9\u6cd5\u5c31\u88ab\u66ff\u6362\u4e86\u3002<\/p>\n
\u8bf4\u5230 OSR \u4f60\u5c31\u7a0d\u5fae\u8033\u719f\u4e86\u4e00\u70b9\uff0c\u662f\u4e0d\u662f\uff1f\u6bd5\u7adf\u5b83\u4e5f\u5076\u73b0\u4e8e\u9762\u8bd5\u73af\u8282\u4e2d\uff0c\u4f5c\u4e3a\u4e00\u4e9b\u9ad8\uff08\u88c5\uff09\u9636\uff08\u903c\uff09\u9762\u8bd5\u9898\u5b58\u5728\u3002<\/p>\n
\u5176\u5b9e\u4e5f\u5c31\u8fd9\u4e48\u56de\u4e8b\u3002<\/p>\n
\u597d\uff0c\u6982\u5ff5\u5c31\u5148\u8bf4\u5230\u8fd9\u91cc\uff0c\u5269\u4e0b\u7684\u5982\u679c\u4f60\u60f3\u8981\u8be6\u7ec6\u4e86\u89e3\uff0c\u53ef\u4ee5\u53bb\u7ffb\u9605\u4e66\u91cc\u9762\u7684\u201c\u7f16\u8bd1\u5bf9\u8c61\u4e0e\u89e6\u53d1\u6761\u4ef6\u201d\u5c0f\u8282\u3002<\/p>\n
\u6211\u4e3b\u8981\u662f\u4e3a\u4e86\u5f15\u51fa\u865a\u62df\u673a\u9488\u5bf9\u70ed\u70b9\u4ee3\u7801\u641e\u4e86\u4e00\u4e9b\u4f18\u5316\u8fd9\u4e2a\u70b9\u3002<\/p>\n
\u57fa\u4e8e\u524d\u9762\u7684\u94fa\u57ab\uff0c\u6211\u5b8c\u5168\u53ef\u4ee5\u5047\u8bbe\u5982\u4e0b\u4e24\u70b9\uff1a<\/p>\n
\n
- 1.\u7531\u4e8e num.getAndAdd \u5e95\u5c42\u4e5f\u662f native \u65b9\u6cd5\u8c03\u7528\uff0c\u6240\u4ee5\u80af\u5b9a\u6709\u5b89\u5168\u70b9\u7684\u4ea7\u751f\u3002<\/li>\n
- 2.\u7531\u4e8e\u865a\u62df\u673a\u5224\u5b9a num.getAndAdd \u662f\u70ed\u70b9\u4ee3\u7801\uff0c\u5c31\u6765\u4e86\u4e00\u6ce2\u4f18\u5316\u3002\u4f18\u5316\u4e4b\u540e\uff0c\u628a\u672c\u6765\u5e94\u8be5\u5b58\u5728\u7684\u5b89\u5168\u70b9\u7ed9\u5e72\u6ca1\u4e86\u3002<\/li>\n<\/ul>\n
<\/p>\n
\u5c0f\u5fc3\u6c42\u8bc1<\/h2>\n
\u5176\u5b9e\u9a8c\u8bc1\u8d77\u6765\u975e\u5e38\u7b80\u5355\uff0c\u524d\u9762\u4e0d\u662f\u8bf4\u4e86\u5417\uff0c\u662f JIT \u4f18\u5316\u641e\u7684\u9b3c\uff0c\u90a3\u6211\u76f4\u63a5\u5173\u95ed JIT \u529f\u80fd\uff0c\u518d\u8dd1\u4e00\u6b21\uff0c\u4e0d\u5c31\u77e5\u9053\u7ed3\u8bba\u4e86\u5417\uff1f<\/p>\n
\u5982\u679c\u5173\u95ed JIT \u529f\u80fd\u540e\uff0c\u4e3b\u7ebf\u7a0b\u5728\u7761\u7720 1000ms \u4e4b\u540e\u7ee7\u7eed\u6267\u884c\uff0c\u8bf4\u660e\u4ec0\u4e48\uff1f<\/p>\n
\u8bf4\u660e\u5faa\u73af\u4f53\u91cc\u9762\u53ef\u4ee5\u8fdb\u5165 safepoint\uff0c\u7a0b\u5e8f\u6267\u884c\u7ed3\u679c\u7b26\u5408\u9884\u671f\u3002<\/p>\n
\u6240\u4ee5\u7ed3\u679c\u662f\u600e\u4e48\u6837\u7684\u5462\uff1f<\/p>\n
\u6211\u53ef\u4ee5\u7528\u4e0b\u9762\u7684\u8fd9\u4e2a\u53c2\u6570\u5173\u95ed JIT\uff1a<\/p>\n
-Djava.compiler=NONE<\/p><\/blockquote>\n
<\/p>\n
\u7136\u540e\u518d\u6b21\u8fd0\u884c\u7a0b\u5e8f\uff1a<\/p>\n
<\/p>\n
\u53ef\u4ee5\u770b\u5230\u5173\u95ed JIT \u4e4b\u540e\uff0c\u4e3b\u7ebf\u7a0b\u5e76\u6ca1\u6709\u7b49\u5f85\u5b50\u7ebf\u7a0b\u8fd0\u884c\u7ed3\u675f\u540e\u624d\u8f93\u51fa num\u3002\u6548\u679c\u7b49\u540c\u4e8e\u524d\u9762\u8bf4\u7684\u628a int \u4fee\u6539\u4e3a long\uff0c\u6216\u8005\u52a0\u5165 Thread.sleep(0) \u8fd9\u6837\u7684\u4ee3\u7801\u3002<\/p>\n
\u56e0\u6b64\u6211\u524d\u9762\u7684\u90a3\u4e24\u70b9\u5047\u8bbe\u662f\u4e0d\u662f\u5c31\u6210\u7acb\u4e86\uff1f<\/p>\n
\u597d\uff0c\u90a3\u4e48\u95ee\u9898\u5c31\u6765\u4e86\uff0c\u8bf4\u597d\u7684\u662f\u5c0f\u5fc3\u6c42\u8bc1\uff0c\u4f46\u662f\u6211\u8fd9\u91cc\u53ea\u662f\u7528\u4e86\u4e00\u4e2a\u53c2\u6570\u5173\u95ed\u4e86 JIT\uff0c\u867d\u7136\u770b\u5230\u4e86\u6548\u679c\uff0c\u4f46\u662f\u603b\u611f\u89c9\u4e2d\u95f4\u8fd8\u7f3a\u70b9\u4e1c\u897f\u3002<\/p>\n
\u7f3a\u4ec0\u4e48\u4e1c\u897f\u5462\uff1f<\/p>\n
\u524d\u9762\u7684\u7a0b\u5e8f\u6211\u5df2\u7ecf\u9a8c\u8bc1\u4e86\uff1a\u7ecf\u8fc7 JIT \u4f18\u5316\u4e4b\u540e\uff0c\u628a\u672c\u6765\u5e94\u8be5\u5b58\u5728\u7684\u5b89\u5168\u70b9\u7ed9\u5e72\u6ca1\u4e86\u3002<\/p>\n
\u4f46\u662f\u8fd9\u53e5\u8bdd\u5176\u5b9e\u8fd8\u662f\u592a\u7b3c\u7edf\u4e86\uff0c\u7ecf\u8fc7 JIT \u4f18\u5316\u4e4b\u524d\u548c\u4e4b\u540e\uff0c\u5206\u522b\u662f\u957f\u4ec0\u4e48\u6837\u5b50\u7684\u5462\uff0c\u80fd\u4e0d\u80fd\u4ece\u4ec0\u4e48\u5730\u65b9\u770b\u51fa\u6765\u5b89\u5168\u70b9\u786e\u5b9e\u662f\u6ca1\u4e86\uff1f<\/p>\n
\u4e0d\u80fd\u6211\u8bf4\u6ca1\u4e86\u5c31\u6ca1\u4e86\uff0c\u8fd9\u5f97\u773c\u89c1\u4e3a\u5b9e\u624d\u884c\u3002<\/p>\n
\u8bf6\uff0c\u4f60\u8bf4\u5de7\u4e0d\u5de7\u3002<\/p>\n
\u6211\u521a\u597d\u77e5\u9053\u6709\u4e2a\u4e1c\u897f\u600e\u4e48\u53bb\u770b\u8fd9\u4e2a\u201c\u4f18\u5316\u4e4b\u524d\u548c\u4e4b\u540e\u201c\u3002<\/p>\n
<\/p>\n
\u6709\u4e2a\u5de5\u5177\u53eb\u505a JITWatch\uff0c\u5b83\u5c31\u80fd\u5e72\u8fd9\u4e2a\u4e8b\u513f\u3002<\/p>\n
https:\/\/github.com\/AdoptOpenJ…<\/a><\/p><\/blockquote>\n
\u5982\u679c\u4f60\u4e4b\u524d\u6ca1\u7528\u8fc7\u8fd9\u4e2a\u5de5\u5177\u7684\u8bdd\uff0c\u53ef\u4ee5\u53bb\u67e5\u67e5\u6559\u7a0b\u3002\u4e0d\u662f\u672c\u6587\u91cd\u70b9\uff0c\u6211\u5c31\u4e0d\u6559\u4e86\uff0c\u4e00\u4e2a\u5de5\u5177\u800c\u5df2\uff0c\u4e0d\u590d\u6742\u7684\u3002<\/p>\n
\u6211\u628a\u4ee3\u7801\u8d34\u5230 JITWatch \u7684\u6c99\u7bb1\u91cc\u9762\uff1a<\/p>\n
<\/p>\n
\u7136\u540e\u70b9\u51fb\u8fd0\u884c\uff0c\u6700\u540e\u5c31\u80fd\u5f97\u5230\u8fd9\u6837\u7684\u4e00\u4e2a\u754c\u9762\u3002<\/p>\n
\u5de6\u8fb9\u662f Java \u6e90\u7801\uff0c\u4e2d\u95f4\u662f Java \u5b57\u8282\u7801\uff0c\u53f3\u8fb9\u662f JIT \u4e4b\u540e\u7684\u6c47\u7f16\u6307\u4ee4\uff1a<\/p>\n
<\/p>\n
\u6211\u6846\u8d77\u6765\u7684\u90e8\u5206\u5c31\u662f JIT \u5206\u5c42\u7f16\u8bd1\u540e\u7684\u4e0d\u540c\u7684\u6c47\u7f16\u6307\u4ee4\u3002<\/p>\n
\u5176\u4e2d C2 \u7f16\u8bd1\u5c31\u662f\u7ecf\u8fc7\u5145\u5206\u7f16\u8bd1\u4e4b\u540e\u7684\u9ad8\u6027\u80fd\u6307\u4ee4\uff0c\u5b83\u4e8e C1 \u7f16\u8bd1\u540e\u7684\u6c47\u7f16\u4ee3\u7801\u6709\u5f88\u591a\u4e0d\u540c\u7684\u5730\u65b9\u3002<\/p>\n
<\/p>\n
\u8fd9\u4e00\u90e8\u5206\u5982\u679c\u4e4b\u524d\u6ca1\u63a5\u89e6\u8fc7\uff0c\u770b\u4e0d\u61c2\u6ca1\u5173\u7cfb\uff0c\u4e5f\u5f88\u6b63\u5e38\uff0c\u6bd5\u7adf\u9762\u8bd5\u4e5f\u4e0d\u4f1a\u8003\u3002<\/p>\n
\u6211\u7ed9\u4f60\u622a\u8fd9\u51e0\u5f20\u7684\u610f\u601d\u5c31\u662f\u8868\u660e\uff0c\u4f60\u53ea\u8981\u77e5\u9053\uff0c\u6211\u73b0\u5728\u5df2\u7ecf\u53ef\u4ee5\u62ff\u5230\u4f18\u5316\u4e4b\u524d\u548c\u4e4b\u540e\u7684\u6c47\u7f16\u6307\u4ee4\u4e86\uff0c\u4f46\u662f\u4ed6\u4eec\u81ea\u5df1\u7684\u5dee\u5f02\u70b9\u5f88\u591a\uff0c\u90a3\u4e48\u6211\u5e94\u8be5\u5173\u6ce8\u7684\u5dee\u5f02\u70b9\u662f\u4ec0\u4e48\u5462\uff1f<\/p>\n
\u5c31\u50cf\u662f\u7ed9\u4f60\u4e24\u4e2a\u6587\u672c\uff0c\u8ba9\u4f60\u627e\u51fa\u5dee\u5f02\u70b9\uff0c\u5f88\u5bb9\u6613\u3002\u4f46\u662f\u5728\u4f17\u591a\u5dee\u5f02\u70b9\u4e2d\uff0c\u54ea\u4e2a\u662f\u6211\u4eec\u5173\u5fc3\u7684\u5462\uff1f<\/p>\n
\u8fd9\u4e2a\u624d\u662f\u5173\u952e\u95ee\u9898\u3002<\/p>\n
\u6211\u4e5f\u4e0d\u77e5\u9053\uff0c\u4f46\u662f\u6211\u627e\u5230\u4e86\u4e0b\u9762\u8fd9\u4e00\u7bc7\u6587\u7ae0\uff0c\u5e26\u9886\u6211\u8d70\u5411\u4e86\u771f\u76f8\u3002<\/p>\n
\u5173\u952e\u6587\u7ae0<\/h2>\n
\u597d\u4e86\uff0c\u524d\u9762\u90fd\u662f\u4e00\u4e9b\u4e0d\u75db\u4e0d\u75d2\u7684\u4e1c\u897f\uff0c\u8fd9\u91cc\u7684\u8fd9\u7bc7\u6587\u7ae0\u624d\u662f\u5173\u952e\u70b9\uff1a<\/p>\n
http:\/\/psy-lob-saw.blogspot.c…<\/a><\/p><\/blockquote>\n
\u56e0\u4e3a\u6211\u5728\u8fd9\u4e2a\u6587\u7ae0\u4e2d\uff0c\u627e\u5230\u4e86 JIT \u4f18\u5316\u4e4b\u540e\uff0c\u5e94\u8be5\u5173\u6ce8\u7684\u201c\u5dee\u5f02\u70b9\u201d\u662f\u4ec0\u4e48\u3002<\/p>\n
\u8fd9\u7bc7\u6587\u7ae0\u7684\u6807\u9898\u53eb\u505a\u300a\u5b89\u5168\u70b9\u7684\u610f\u4e49\u3001\u526f\u4f5c\u7528\u4ee5\u53ca\u5f00\u9500\u300b\uff1a<\/p>\n
<\/p>\n
\u4f5c\u8005\u662f\u4e00\u4f4d\u53eb\u505a nitsanw \u7684\u5927\u4f6c\uff0c\u4ece\u4ed6\u535a\u5ba2\u91cc\u9762\u7684\u6587\u7ae0\u770b\uff0c\u5728 JVM \u548c\u6027\u80fd\u4f18\u5316\u65b9\u9762\u6709\u7740\u5f88\u6df1\u7684\u9020\u8be3\uff0c\u4e0a\u9762\u7684\u6587\u7ae0\u5c31\u53d1\u5e03\u4e8e\u4ed6\u7684\u535a\u5ba2\u3002<\/p>\n
\u8fd9\u662f\u4ed6\u7684 github \u5730\u5740\uff1a<\/p>\n
https:\/\/github.com\/nitsanw<\/a><\/p><\/blockquote>\n
<\/p>\n
\u7528\u7684\u5934\u50cf\u662f\u4e00\u5934\u7266\u725b\uff0c\u90a3\u6211\u5c31\u53eb\u4ed6\u725b\u54e5\u5427\uff0c\u6bd5\u7adf\u662f\u771f\u7684\u725b\u3002<\/p>\n
\u540c\u65f6\u725b\u54e5\u5c31\u804c\u4e8e Azul \u516c\u53f8\uff0c\u548c R \u5927\u662f\u540c\u4e8b\uff1a<\/p>\n
<\/p>\n
\u4ed6\u8fd9\u7bc7\u6587\u7ae0\u7b97\u662f\u628a\u5b89\u5168\u70b9\u6252\u4e86\u4e2a\u5e72\u51c0\uff0c\u4f46\u662f\u5185\u5bb9\u975e\u5e38\u591a\uff0c\u6211\u4e0d\u53ef\u80fd\u9762\u9762\u4ff1\u5230\uff0c\u53ea\u80fd\u6311\u548c\u672c\u6587\u76f8\u5173\u5ea6\u975e\u5e38\u5927\u7684\u5730\u65b9\u8fdb\u884c\u7b80\u8ff0\uff0c\u4f46\u662f\u771f\u7684\u5f3a\u70c8\u5efa\u8bae\u4f60\u8bfb\u8bfb\u539f\u6587\u3002\u6587\u7ae0\u4e5f\u5206\u4e3a\u4e86\u4e0a\u4e0b\u4e24\u96c6\uff0c\u8fd9\u662f\u4e0b\u96c6\u7684\u5730\u5740\uff1a<\/p>\n
http:\/\/psy-lob-saw.blogspot.c…<\/a><\/p><\/blockquote>\n
\u770b\u5b8c\u4e4b\u540e\uff0c\u4f60\u5c31\u77e5\u9053\uff0c\u4ec0\u4e48\u53eb\u505a\u900f\u5f7b\uff0c\u4ec0\u4e48\u53eb\u505a\uff1a<\/p>\n
<\/p>\n
\u5728\u725b\u54e5\u7684\u6587\u7ae0\u4e2d\u5206\u4e3a\u4e86\u4e0b\u9762\u8fd9\u51e0\u4e2a\u5c0f\u8282\uff1a<\/p>\n
\n
- What’s a Safepoint?\uff08\u5565\u662f\u5b89\u5168\u70b9\uff1f\uff09<\/li>\n
- When is my thread at a safepoint?\uff08\u7ebf\u7a0b\u5565\u65f6\u5019\u5904\u4e8e\u5b89\u5168\u70b9\uff1f\uff09<\/li>\n
- Bringing a Java Thread to a Safepoint\u3002\uff08\u5c06\u4e00\u4e2aJava\u7ebf\u7a0b\u5e26\u5230\u4e00\u4e2a\u5b89\u5168\u70b9\uff09<\/li>\n
- All Together Now\u3002\uff08\u641e\u51e0\u4e2a\u4f8b\u5b50\u8dd1\u8dd1\uff09<\/li>\n
- Final Summary And Testament\u3002\uff08\u603b\u7ed3\u548c\u5631\u5490\uff09<\/li>\n<\/ul>\n
\u548c\u672c\u6587\u91cd\u70b9\u76f8\u5173\u7684\u662f\u201c\u5c06\u4e00\u4e2aJava\u7ebf\u7a0b\u5e26\u5230\u4e00\u4e2a\u5b89\u5168\u70b9\u201d\u8fd9\u4e2a\u90e8\u5206\u3002<\/p>\n
\u6211\u7ed9\u4f60\u89e3\u6790\u4e00\u4e0b\uff1a<\/p>\n
<\/p>\n
\u8fd9\u4e00\u6bb5\u4e3b\u8981\u5728\u8bf4 Java \u7ebf\u7a0b\u9700\u8981\u6bcf\u9694\u4e00\u4e2a\u65f6\u95f4\u95f4\u9694\u53bb\u8f6e\u8be2\u4e00\u4e2a\u201c\u5b89\u5168\u70b9\u6807\u8bc6\u201d\uff0c\u5982\u679c\u8fd9\u4e2a\u6807\u8bc6\u544a\u8bc9\u7ebf\u7a0b\u201c\u8bf7\u524d\u5f80\u5b89\u5168\u70b9\u201d\uff0c\u90a3\u4e48\u5b83\u5c31\u8fdb\u5165\u5230\u5b89\u5168\u70b9\u7684\u72b6\u6001\u3002<\/p>\n
\u4f46\u662f\u8fd9\u4e2a\u8f6e\u8be2\u662f\u6709\u4e00\u5b9a\u7684\u6d88\u8017\u7684\uff0c\u6240\u4ee5\u9700\u8981 keep safepoint polls to a minimum\uff0c\u4e5f\u5c31\u662f\u8bf4\u8981\u51cf\u5c11\u5b89\u5168\u70b9\u7684\u8f6e\u8be2\u3002\u56e0\u6b64\uff0c\u5173\u4e8e\u5b89\u5168\u70b9\u8f6e\u8be2\u89e6\u53d1\u7684\u65f6\u95f4\u5c31\u5f88\u6709\u8bb2\u7a76\u3002<\/p>\n
\u65e2\u7136\u8fd9\u91cc\u63d0\u5230\u8f6e\u8be2\u4e86\uff0c\u90a3\u4e48\u5c31\u5f97\u8bf4\u4e00\u4e0b\u6211\u4eec\u793a\u4f8b\u4ee3\u7801\u91cc\u9762\u7684\u8fd9\u4e2a sleep \u65f6\u95f4\u4e86\uff1a<\/p>\n
<\/p>\n
\u6709\u7684\u8bfb\u8005\u628a\u65f6\u95f4\u6539\u7684\u77ed\u4e86\u4e00\u70b9\uff0c\u6bd4\u5982 500ms\uff0c700ms \u4e4b\u7c7b\u7684\uff0c\u53d1\u73b0\u7a0b\u5e8f\u6b63\u5e38\u7ed3\u675f\u4e86\uff1f<\/p>\n
\u4e3a\u4ec0\u4e48\uff1f<\/p>\n
\u56e0\u4e3a\u8f6e\u8be2\u7684\u65f6\u95f4\u7531 -XX:GuaranteedSafepointInterval \u9009\u9879\u63a7\u5236\uff0c\u8be5\u9009\u9879\u9ed8\u8ba4\u4e3a 1000ms\uff1a<\/p>\n
<\/p>\n
\u6240\u4ee5\uff0c\u5f53\u4f60\u7684\u7761\u7720\u65f6\u95f4\u6bd4 1000ms \u5c0f\u592a\u591a\u7684\u65f6\u5019\uff0c\u5b89\u5168\u70b9\u7684\u8f6e\u8be2\u8fd8\u6ca1\u5f00\u59cb\uff0c\u4f60\u5c31 sleep \u7ed3\u675f\u4e86\uff0c\u5f53\u7136\u89c2\u5bdf\u4e0d\u5230\u4e3b\u7ebf\u7a0b\u7b49\u5f85\u7684\u73b0\u8c61\u4e86\u3002<\/p>\n
\u597d\u4e86\uff0c\u8fd9\u4e2a\u53ea\u662f\u968f\u53e3\u63d0\u4e00\u53e5\uff0c\u56de\u5230\u725b\u54e5\u7684\u6587\u7ae0\u4e2d\uff0c\u4ed6\u8bf4\u7efc\u5408\u5404\u79cd\u56e0\u7d20\uff0c\u5173\u4e8e\u5b89\u5168\u70b9\u7684\u8f6e\u8be2\uff0c\u53ef\u4ee5\u5728\u4ee5\u4e0b\u5730\u65b9\u8fdb\u884c\uff1a<\/p>\n
\u7b2c\u4e00\u4e2a\u5730\u65b9\uff1a<\/strong><\/p>\n
Between any 2 bytecodes while running in the interpreter (effectively)<\/p><\/blockquote>\n
\u5728\u89e3\u91ca\u5668\u6a21\u5f0f\u4e0b\u8fd0\u884c\u65f6\uff0c\u5728\u4efb\u4f55 2 \u4e2a\u5b57\u8282\u7801\u4e4b\u95f4\u90fd\u53ef\u4ee5\u8fdb\u884c\u5b89\u5168\u70b9\u7684\u8f6e\u8be2\u3002<\/p>\n
\u8981\u7406\u89e3\u8fd9\u53e5\u8bdd\uff0c\u5c31\u9700\u8981\u4e86\u89e3\u89e3\u91ca\u5668\u6a21\u5f0f\u4e86\uff0c\u4e0a\u4e2a\u56fe\uff1a<\/p>\n
<\/p>\n
\u4ece\u56fe\u4e0a\u53ef\u4ee5\u77e5\u9053\uff0c\u89e3\u91ca\u5668\u548c\u7f16\u8bd1\u5668\u4e4b\u95f4\u662f\u76f8\u8f85\u76f8\u6210\u7684\u5173\u7cfb\u3002<\/p>\n
\u53e6\u5916\uff0c\u53ef\u4ee5\u4f7f\u7528 -Xint \u542f\u52a8\u53c2\u6570\uff0c\u5f3a\u5236\u865a\u62df\u673a\u8fd0\u884c\u4e8e\u201c\u89e3\u91ca\u6a21\u5f0f\u201d\uff1a<\/p>\n
<\/p>\n
\u6211\u4eec\u5b8c\u5168\u53ef\u4ee5\u8bd5\u4e00\u8bd5\u8fd9\u4e2a\u53c2\u6570\u561b\uff1a<\/p>\n
<\/p>\n
\u7a0b\u5e8f\u6b63\u5e38\u505c\u4e0b\u6765\u4e86\uff0c\u4e3a\u4ec0\u4e48\uff1f<\/p>\n
\u521a\u521a\u624d\u8bf4\u4e86\uff1a<\/p>\n
\u5728\u89e3\u91ca\u5668\u6a21\u5f0f\u4e0b\u8fd0\u884c\u65f6\uff0c\u5728\u4efb\u4f55 2 \u4e2a\u5b57\u8282\u7801\u4e4b\u95f4\u90fd\u53ef\u4ee5\u8fdb\u884c\u5b89\u5168\u70b9\u7684\u8f6e\u8be2\u3002<\/p><\/blockquote>\n
\u7b2c\u4e8c\u4e2a\u5730\u65b9\uff1a<\/strong><\/p>\n
On ‘non-counted’ loop back edge in C1\/C2 compiled code<\/p><\/blockquote>\n
\u5728 C1\/C2 \u7f16\u8bd1\u4ee3\u7801\u4e2d\u7684 “\u975e\u8ba1\u6570 “\u5faa\u73af\u7684\u6bcf\u6b21\u5faa\u73af\u4f53\u7ed3\u675f\u4e4b\u540e\u3002<\/p>\n
\u5173\u4e8e\u8fd9\u4e2a\u201c\u8ba1\u6570\u5faa\u73af\u201d\u548c\u201c\u975e\u8ba1\u7b97\u5faa\u73af\u201d\u6211\u5728\u4e0a\u96c6\u91cc\u9762\u5df2\u7ecf\u8bf4\u8fc7\u4e86\uff0c\u4e5f\u6f14\u793a\u8fc7\u4e86\uff0c\u5c31\u662f\u628a int \u4fee\u6539\u4e3a long\uff0c\u8ba9\u201c\u8ba1\u6570\u5faa\u73af\u201d\u53d8\u6210\u201c\u975e\u8ba1\u7b97\u5faa\u73af\u201d\uff0c\u5c31\u4e0d\u8d58\u8ff0\u4e86\u3002<\/p>\n
\u53cd\u6b63\u6211\u4eec\u77e5\u9053\u8fd9\u91cc\u8bf4\u7684\u6ca1\u6bdb\u75c5\u5c31\u884c\u3002<\/p>\n
\u7b2c\u4e09\u4e2a\u5730\u65b9\uff1a<\/strong><\/p>\n
\u8fd9\u662f\u524d\u534a\u53e5\uff1aMethod entry\/exit (entry for Zing, exit for OpenJDK) in C1\/C2 compiled code.<\/p><\/blockquote>\n
\u5728 C1\/C2 \u7f16\u8bd1\u4ee3\u7801\u4e2d\u7684\u65b9\u6cd5\u5165\u53e3\u6216\u8005\u51fa\u53e3\u5904\uff08Zing \u4e3a\u5165\u53e3\uff0cOpenJDK \u4e3a\u51fa\u53e3\uff09\u3002<\/p>\n
\u524d\u534a\u53e5\u5f88\u597d\u7406\u89e3\uff0c\u5bf9\u4e8e\u6211\u4eec\u5e38\u7528\u7684 OpenJDK \u6765\u8bf4\uff0c\u5373\u4f7f\u7ecf\u8fc7\u4e86 JIT \u4f18\u5316\uff0c\u4f46\u662f\u5728\u65b9\u6cd5\u7684\u5165\u53e3\u5904\u8fd8\u662f\u8bbe\u7f6e\u4e86\u4e00\u4e2a\u53ef\u4ee5\u8fdb\u884c\u5b89\u5168\u70b9\u8f6e\u8be2\u7684\u5730\u65b9\u3002<\/p>\n
\u4e3b\u8981\u662f\u5173\u6ce8\u540e\u534a\u53e5\uff1a<\/p>\n
Note that the compiler will remove these safepoint polls when methods are inlined.<\/p><\/blockquote>\n
\u5f53\u65b9\u6cd5\u88ab\u5185\u8054\u65f6\u7f16\u8bd1\u5668\u4f1a\u5220\u9664\u8fd9\u4e9b\u5b89\u5168\u70b9\u8f6e\u8be2<\/strong>\u3002<\/p>\n
\u8fd9\u4e0d\u5c31\u662f\u6211\u4eec\u793a\u4f8b\u4ee3\u7801\u7684\u60c5\u51b5\u5417\uff1f<\/p>\n
\u672c\u6765\u6709\u5b89\u5168\u70b9\uff0c\u4f46\u662f\u88ab\u4f18\u5316\u6ca1\u4e86\u3002\u8bf4\u660e\u8fd9\u79cd\u60c5\u51b5\u662f\u771f\u5b9e\u5b58\u5728\u7684\u3002<\/p>\n
<\/p>\n
\u7136\u540e\u6211\u4eec\u63a5\u7740\u5f80\u4e0b\u770b\uff0c\u5c31\u80fd\u770b\u5230\u6211\u4e00\u76f4\u5728\u627e\u7684\u201c\u5dee\u5f02\u70b9\u201d\u4e86\uff1a<\/p>\n
<\/p>\n
\u725b\u54e5\u8bf4\uff0c\u5982\u679c\u6709\u4eba\u60f3\u770b\u5230\u5b89\u5168\u70b9\u8f6e\u8be2\uff0c\u90a3\u4e48\u53ef\u4ee5\u52a0\u4e0a\u8fd9\u4e2a\u542f\u52a8\u53c2\u6570\uff1a<\/p>\n
-XX:+PrintAssembly<\/p><\/blockquote>\n
\u7136\u540e\u5728\u8f93\u51fa\u91cc\u9762\u627e\u4e0b\u9762\u7684\u5173\u952e\u8bcd\uff1a<\/p>\n
\n
- \u5982\u679c\u662f OpenJDK\uff0c\u5c31\u627e {poll} \u6216 {poll return} \uff0c\u8fd9\u5c31\u662f\u5bf9\u5e94\u7684\u5b89\u5168\u70b9\u6307\u4ee4\u3002<\/li>\n
- \u5982\u679c\u662f Zing\uff0c\u5c31\u627e tls.pls_self_suspend \u6307\u4ee4<\/li>\n<\/ul>\n
\u5b9e\u64cd\u4e00\u628a\u5c31\u662f\u8fd9\u6837\u7684\uff1a<\/p>\n
<\/p>\n
\u786e\u5b9e\u627e\u5230\u4e86\u7c7b\u4f3c\u7684\u5173\u952e\u5b57\uff0c\u4f46\u662f\u5728\u63a7\u5236\u53f0\u8f93\u51fa\u7684\u6c47\u7f16\u592a\u591a\u4e86\uff0c\u6839\u672c\u6ca1\u6cd5\u5206\u6790\u3002<\/p>\n
\u6ca1\u5173\u7cfb\uff0c\u8fd9\u4e0d\u91cd\u8981\uff0c\u91cd\u8981\u7684\u662f\u6211\u5230\u4e86\u8fd9\u4e2a\u5173\u952e\u7684\u6307\u4ee4\uff1a{poll}<\/p>\n
\u4e5f\u5c31\u662f\u8bf4\uff0c\u5982\u679c\u5728\u521d\u59cb\u7684\u6c47\u7f16\u4e2d\u6709 {poll} \u6307\u4ee4\uff0c\u4f46\u662f\u5728\u7ecf\u8fc7 JIT \u5145\u5206\u4f18\u5316\u4e4b\u540e\u7684\u4ee3\u7801\uff0c\u4e5f\u5c31\u662f\u524d\u9762\u8bf4\u7684 C2 \u9636\u6bb5\u7684\u6c47\u7f16\u6307\u4ee4\u91cc\u9762\uff0c\u627e\u4e0d\u5230 {poll} \u8fd9\u4e2a\u6307\u4ee4\uff0c\u5c31\u8bf4\u660e\u5b89\u5168\u70b9\u786e\u5b9e\u662f\u88ab\u5e72\u6389\u4e86\u3002<\/p>\n
\u6240\u4ee5\uff0c\u5728 JITWatch \u91cc\u9762\uff0c\u5f53\u6211\u9009\u62e9\u67e5\u770b for \u5faa\u73af\uff08\u70ed\u70b9\u4ee3\u7801\uff09\u5728 C1 \u9636\u6bb5\u7684\u7f16\u8bd1\u7ed3\u679c\u7684\u65f6\u5019\uff0c\u53ef\u4ee5\u770b\u770b\u6709 {poll} \u6307\u4ee4\uff1a<\/p>\n
<\/p>\n
\u4f46\u662f\uff0c\u5f53\u6211\u9009\u62e9 C2 \u9636\u6bb5\u7684\u7f16\u8bd1\u7ed3\u679c\u7684\u65f6\u5019\uff0c{poll} \u6307\u4ee4\u786e\u5b9e\u90fd\u627e\u4e0d\u5230\u4e86\uff1a<\/p>\n
<\/p>\n
\u63a5\u7740\uff0c\u5982\u679c\u6211\u628a\u4ee3\u7801\u4fee\u6539\u4e3a\u8fd9\u6837\uff0c\u4e5f\u5c31\u662f\u524d\u9762\u8bf4\u7684\u4f1a\u6b63\u5e38\u7ed3\u675f\u7684\u4ee3\u7801\uff1a<\/p>\n
<\/p>\n
\u6b63\u5e38\u7ed3\u675f\uff0c\u8bf4\u660e\u5faa\u73af\u4f53\u5185\u53ef\u4ee5\u8fdb\u5165\u5b89\u5168\u70b9\uff0c\u4e5f\u5c31\u662f\u8bf4\u660e\u6709 {poll} \u6307\u4ee4\u3002<\/p>\n
\u6240\u4ee5\uff0c\u518d\u6b21\u901a\u8fc7 JITWarch \u67e5\u770b C2 \u7684\u6c47\u7f16\uff0c\u679c\u7136\u770b\u5230\u4e86\u5b83\uff1a<\/p>\n
<\/p>\n
\u4e3a\u4ec0\u4e48\u5462\uff1f<\/p>\n
\u4ece\u6700\u7ec8\u8f93\u51fa\u7684\u6c47\u7f16\u4e0a\u6765\u770b\uff0c\u56e0\u4e3a Thread.sleep(0) \u8fd9\u884c\u4ee3\u7801\u7684\u5b58\u5728\uff0c\u963b\u6b62\u4e86 JIT \u505a\u8fc7\u4e8e\u6fc0\u8fdb\u7684\u4f18\u5316\u3002<\/p>\n
\u90a3\u4e48\u4e3a\u4ec0\u4e48 sleep \u4f1a\u963b\u6b62 JIT \u505a\u8fc7\u4e8e\u6fc0\u8fdb\u7684\u4f18\u5316\u5462\uff1f<\/p>\n
\u597d\u4e86\uff0c<\/p>\n
\u522b\u95ee\u4e86\uff0c<\/p>\n
\u5c31\u5230\u8fd9\u5427\uff0c<\/p>\n
\u518d\u95ee\uff0c<\/p>\n
\u5c31\u4e0d\u793c\u8c8c\u4e86\u3002<\/p>\n
<\/p>\n
\u725b\u54e5\u7684\u6848\u4f8b<\/h2>\n
\u725b\u54e5\u7684\u6587\u7ae0\u4e2d\u7ed9\u4e86\u4e0b\u9762\u4e94\u4e2a\u6848\u4f8b\uff0c\u6bcf\u4e2a\u6848\u4f8b\u90fd\u6709\u5bf9\u5e94\u7684\u4ee3\u7801\uff1a<\/p>\n
\n
- Example 0: Long TTSP Hangs Application<\/li>\n
- Example 1: More Running Threads -> Longer TTSP, Higher Pause Times<\/li>\n
- Example 2: Long TTSP has Unfair Impact<\/li>\n
- Example 3: Safepoint Operation Cost Scale<\/li>\n
- Example 4: Adding Safepoint Polls Stops Optimization<\/li>\n<\/ul>\n
\u6211\u4e3b\u8981\u5e26\u5927\u5bb6\u770b\u770b\u7b2c 0 \u4e2a\u548c\u7b2c 4 \u4e2a\uff0c\u8001\u6709\u610f\u601d\u4e86\u3002<\/p>\n
\u7b2c 0 \u4e2a\u6848\u4f8b<\/h3>\n
\u5b83\u7684\u4ee3\u7801\u662f\u8fd9\u6837\u7684\uff1a<\/p>\n
public class WhenWillItExit {\n public static void main(String[] argc) throws InterruptedException {\n Thread t = new Thread(() -> {\n long l = 0;\n for (int i = 0; i < Integer.MAX_VALUE; i++) {\n for (int j = 0; j < Integer.MAX_VALUE; j++) {\n if ((j & 1) == 1)\n l++;\n }\n }\n System.out.println("How Odd:" + l);\n });\n t.setDaemon(true);\n t.start();\n Thread.sleep(5000);\n }\n}<\/code><\/pre>\n\u725b\u54e5\u662f\u8fd9\u6837\u63cf\u8ff0\u8fd9\u4e2a\u4ee3\u7801\u7684\uff1a<\/p>\n
<\/p>\n
\u4ed6\u8bf4\u8fd9\u4e2a\u4ee3\u7801\u5e94\u8be5\u662f\u5728 5 \u79d2\u4e4b\u540e\u7ed3\u675f\uff0c\u4f46\u662f\u5b9e\u9645\u4e0a\u5b83\u4f1a\u4e00\u76f4\u8fd0\u884c\u4e0b\u53bb\uff0c\u9664\u975e\u4f60\u7528 kill -9 \u547d\u4ee4\u5f3a\u884c\u505c\u6b62\u5b83\u3002<\/p>\n
\u4f46\u662f\u5f53\u6211\u628a\u4ee3\u7801\u7c98\u8d34\u5230 IDEA \u91cc\u9762\u8fd0\u884c\u8d77\u6765\uff0c5 \u79d2\u4e4b\u540e\uff0c\u7a0b\u5e8f\u505c\u4e86\uff0c\u5c31\u7565\u663e\u5c34\u5c2c\u3002<\/p>\n
\u6211\u5efa\u8bae\u4f60\u4e5f\u7c98\u51fa\u6765\u8dd1\u4e00\u4e0b\u3002<\/p>\n
\u8fd9\u91cc\u4e3a\u4ec0\u4e48\u548c\u725b\u54e5\u8bf4\u7684\u8fd0\u884c\u7ed3\u679c\u4e0d\u4e00\u6837\u5462\uff1f<\/p>\n
\u8bc4\u8bba\u533a\u4e5f\u6709\u4eba\u95ee\u51fa\u4e86\u8fd9\u4e2a\u95ee\u9898\uff1a<\/p>\n
<\/p>\n
\u4e8e\u662f\u725b\u54e5\u53c8\u5199\u4e86\u4e00\u7bc7\u4e0b\u96c6\uff0c\u8be6\u7ec6\u7684\u89e3\u91ca\u4e86\u4e3a\u4ec0\u4e48\uff1a<\/p>\n
http:\/\/psy-lob-saw.blogspot.c…<\/a><\/p><\/blockquote>\n
\u7b80\u5355\u6765\u8bf4\u5c31\u662f\u4ed6\u662f\u5728 Eclipse \u91cc\u9762\u8dd1\u7684\uff0c\u800c Eclipse \u5e76\u4e0d\u662f\u7528\u7684 javac \u6765\u7f16\u8bd1\uff0c\u800c\u662f\u7528\u7684\u81ea\u5df1\u7684\u7f16\u8bd1\u5668\u3002<\/p>\n
\u7f16\u8bd1\u5668\u5dee\u5f02\u5bfc\u81f4\u5b57\u8282\u7801\u7684\u5dee\u5f02\uff0c\u4ece\u800c\u5bfc\u81f4\u8fd0\u884c\u7ed3\u679c\u7684\u5dee\u5f02\uff1a<\/p>\n
<\/p>\n
\u7136\u540e\u725b\u54e5\u901a\u8fc7\u4e00\u987f\u5206\u6790\uff0c\u7ed9\u51fa\u4e86\u8fd9\u6837\u7684\u4e00\u6bb5\u4ee3\u7801\uff0c<\/p>\n
<\/p>\n
\u548c\u4e4b\u524d\u7684\u4ee3\u7801\u552f\u4e00\u4e0d\u4e00\u6837\u7684\u5730\u65b9\uff0c\u5c31\u662f\u5728\u5b50\u7ebf\u7a0b\u91cc\u9762\u8c03\u7528 countOdds \u65b9\u6cd5\u4e4b\u524d\uff0c\u5728\u4e3b\u7ebf\u7a0b\u91cc\u9762\u5148\u8fdb\u884c\u4e86 10w \u6b21\u7684\u8fd0\u884c\u8c03\u7528\u3002<\/p>\n
\u8fd9\u6837\u6539\u9020\u4e4b\u540e\u4ee3\u7801\u8fd0\u884c\u8d77\u6765\u5c31\u4e0d\u4f1a\u5728 5 \u79d2\u4e4b\u540e\u505c\u6b62\u4e86\uff0c\u5fc5\u987b\u8981\u5f3a\u884c kill \u624d\u884c\u3002<\/p>\n
\u4e3a\u4ec0\u4e48\u5462\uff1f<\/p>\n
\u522b\u95ee\uff0c\u95ee\u5c31\u662f\u7b54\u6848\u5c31\u5728\u4ed6\u7684\u4e0b\u96c6\u91cc\u9762\uff0c\u81ea\u5df1\u53bb\u7ffb\uff0c\u5199\u7684\u975e\u5e38\u8be6\u7ec6\u3002<\/p>\n
\u540c\u65f6\u5728\u4e0b\u96c6\u4e2d\uff0c\u725b\u54e5\u8fd8\u975e\u5e38\u8d34\u5fc3\u7684\u7ed9\u4f60\u8d34\u51fa\u4e86\u4ed6\u603b\u7ed3\u7684\u516d\u79cd\u5faa\u73af\u7684\u5199\u6cd5\uff0c\u90a3\u4e9b\u7b97\u662f\u201ccounted Loops\u201d\uff0c\u5efa\u8bae\u4ed4\u7ec6\u8fa8\u522b\uff1a<\/p>\n
<\/p>\n
\u7b2c 4 \u4e2a\u6848\u4f8b<\/h3>\n
\u8fd9\u4e2a\u6848\u4f8b\u662f\u4e00\u4e2a\u57fa\u51c6\u6d4b\u8bd5\uff0c\u725b\u54e5\u8bf4\u5b83\u662f\u6765\u81ea Netty \u7684\u4e00\u4e2a issue\uff1a<\/p>\n
<\/p>\n
\u8fd9\u91cc\u600e\u4e48\u7a81\u7136\u63d0\u5230 Netty \u4e86\u5462\uff1f<\/p>\n
\u725b\u54e5\u7ed9\u4e86\u4e00\u4e2a\u8d85\u94fe\u63a5\uff1a<\/p>\n
https:\/\/github.com\/netty\/nett…<\/a><\/p><\/blockquote>\n
\u8fd9\u4e2a pr \u91cc\u9762\u8ba8\u8bba\u7684\u5185\u5bb9\u975e\u5e38\u7684\u591a\uff0c\u5176\u4e2d\u4e00\u4e2a\u4e89\u8bba\u7684\u70b9\u5c31\u662f\u5faa\u73af\u5230\u5e95\u7528 int \u8fd8\u662f long\u3002<\/p>\n
\u8fd9\u4e2a\u54e5\u4eec\u5199\u4e86\u4e00\u4e2a\u57fa\u51c6\u6d4b\u8bd5\uff0c\u6d4b\u8bd5\u7ed3\u679c\u663e\u793a\u7528 int \u548c long \u4f3c\u4e4e\u6ca1\u5565\u5dee\u522b\uff1a<\/p>\n
<\/p>\n
\u9700\u8981\u8bf4\u660e\u7684\u662f\uff0c\u4e3a\u4e86\u622a\u56fe\u65b9\u4fbf\uff0c\u6211\u622a\u56fe\u7684\u65f6\u5019\u628a\u8fd9\u4e2a\u8001\u54e5\u7684\u57fa\u51c6\u6d4b\u8bd5\u5220\u9664\u4e86\u3002\u5982\u679c\u4f60\u60f3\u770b\u4ed6\u7684\u57fa\u51c6\u6d4b\u8bd5\u4ee3\u7801\uff0c\u53ef\u4ee5\u901a\u8fc7\u524d\u9762\u8bf4\u7684\u94fe\u63a5\u53bb\u627e\u5230\u3002<\/p>\n
\u7136\u540e\u8fd9\u4e2a\u770b\u8d77\u6765\u5934\u53d1\u5c31\u5f88\u8302\u76db\u7684\u8001\u54e5\u76f4\u63a5\u7528\u53ec\u5524\u672f\u53ec\u5524\u4e86\u725b\u54e5\uff1a<\/p>\n
<\/p>\n
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