{"id":1201,"date":"2015-04-08T22:14:19","date_gmt":"2015-04-08T14:14:19","guid":{"rendered":"http:\/\/coderbee.net\/?p=1201"},"modified":"2015-04-23T20:29:56","modified_gmt":"2015-04-23T12:29:56","slug":"java-flight-recordings-jfr-part-2-%e7%94%a8-jfr-%e5%ae%9a%e4%bd%8d%e6%80%a7%e8%83%bd%e9%97%ae%e9%a2%98","status":"publish","type":"post","link":"https:\/\/coderbee.net\/index.php\/jvm\/20150408\/1201","title":{"rendered":"Java Flight Recordings (JFR) &#8212; part 2 \u7528 JFR \u5b9a\u4f4d\u6027\u80fd\u95ee\u9898"},"content":{"rendered":"<h2>\u5185\u5bb9\u76ee\u5f55<\/h2>\n<ul>\n<li><a href=\"#JFR-Overhead\">JFR \u6982\u89c8<\/a><\/li>\n<li><a href=\"#Find-Bottlenecks\">\u627e\u51fa\u74f6\u9888<\/a><\/li>\n<li><a href=\"#Garbage-Collection-Performance\">GC \u6027\u80fd<\/a><\/li>\n<li><a href=\"#Synchronization-Performance\">\u540c\u6b65\u6027\u80fd<\/a><\/li>\n<li><a href=\"#I\/O-Performance\">I\/O \u6027\u80fd<\/a><\/li>\n<li><a href=\"#Code-Execution-Performance\">\u4ee3\u7801\u6267\u884c\u6027\u80fd<\/a><\/li>\n<\/ul>\n<p><a name=\"JFR-Overhead\"><\/a><\/p>\n<h2>\u4e00\u3001JFR \u6982\u89c8<\/h2>\n<p><a name=\"Find-Bottlenecks\"><\/a><\/p>\n<h2>\u4e8c\u3001\u627e\u51fa\u74f6\u9888<\/h2>\n<p>\u4e0d\u540c\u7684\u5e94\u7528\u6709\u4e0d\u540c\u7684\u74f6\u9888\u3002\u5bf9\u4e8e\u6709\u4e9b\u5e94\u7528\uff0c\u74f6\u9888\u53ef\u80fd\u662f\u7b49\u5f85 I\/O \u6216\u7f51\u7edc\uff0c\u53ef\u80fd\u662f\u7ebf\u7a0b\u4e4b\u95f4\u7684\u540c\u6b65\uff0c\u6216\u8005\u662f\u5b9e\u9645\u7684 CPU \u4f7f\u7528\u3002\u5bf9\u4e8e\u5176\u4ed6\uff0c\u74f6\u9888\u53ef\u80fd\u662f GC \u65f6\u95f4\u3002\u5f88\u53ef\u80fd\u5e94\u7528\u6709\u4e0d\u6b62\u4e00\u4e2a\u74f6\u9888\u3002<\/p>\n<p>\u627e\u51fa\u5e94\u7528\u74f6\u9888\u7684\u4e00\u4e2a\u65b9\u6cd5\u662f\u67e5\u770b <code>Events<\/code> \u9009\u9879\u5361\u3002\u8fd9\u662f\u4e00\u4e2a\u9ad8\u7ea7\u9009\u9879\u5361\uff0c\u53ef\u4ee5\u505a\u4e0d\u5c11\u4e8b\u60c5\u3002\u5982\u4e0b\u56fe\uff0c\u53ef\u4ee5\u9009\u62e9\u81ea\u5df1\u611f\u5174\u8da3\u7684\u4e8b\u4ef6\uff1a<br \/>\n<img decoding=\"async\" src=\"\/\/coderbee.net\/wp-content\/uploads\/2015\/04\/jfr-event-types.png\" alt=\"jfr-event-types\" \/><\/p>\n<p><!--more--><\/p>\n<p>\u751f\u6210\u7684\u7ed3\u679c\u56fe\u793a\uff1a<br \/>\n<img decoding=\"async\" src=\"\/\/coderbee.net\/wp-content\/uploads\/2015\/04\/jfr-thread-event.png\" alt=\"jfr-thread-event\" \/><\/p>\n<p>\u5728\u201cGraph\u201d\u9009\u9879\u5361\u91cc\uff0c\u6bcf\u4e00\u884c\u662f\u4e00\u4e2a\u7ebf\u7a0b\uff0c\u6bcf\u4e2a\u7ebf\u7a0b\u53ef\u4ee5\u6709\u591a\u884c\u3002\u5728\u4e0a\u56fe\u4e2d\uff0c\u6bcf\u4e2a\u7ebf\u7a0b\u90fd\u6709\u4e00\u884c\uff0c\u8868\u793a Java \u5e94\u7528\u7a0b\u5e8f\u7684\u65f6\u95f4\uff0c\u5728 \u201cEvent Types\u201d\u9009\u9879\u5361\u91cc\u5141\u8bb8\u5f55\u5236\u7684\u3002\u88ab\u9009\u4e2d\u7684 Java \u5e94\u7528\u7a0b\u5e8f\u4e8b\u4ef6\u90fd\u6709\u4e2a\u91cd\u8981\u7684\u5c5e\u6027\u662f\u7ebf\u7a0b\u5931\u901f\u4e8b\u4ef6\u3002\u7ebf\u7a0b\u5931\u901f\u8868\u660e\u7ebf\u7a0b\u5728\u4e8b\u4ef6\u671f\u95f4\u6ca1\u6709\u8fd0\u884c\u4f60\u7684\u5e94\u7528\u7a0b\u5e8f\uff0c\u5b83\u4eec\u662f\u6301\u7eed\u4e8b\u4ef6\u3002\u6301\u7eed\u4e8b\u4ef6\u6d4b\u91cf\u4e86\u5e94\u7528\u7a0b\u5e8f\u6ca1\u6709\u8fd0\u884c\u7684\u671f\u95f4\u3002<\/p>\n<p>\u4ece\u201cEvent Types\u201d \u9009\u9879\u5361\u91cc\u6bcf\u79cd\u989c\u8272\u5bf9\u5e94\u4e0d\u540c\u7684\u4e8b\u4ef6\u3002<\/p>\n<p><strong>Java Monitor Wait<\/strong> \u4e8b\u4ef6\u8868\u793a\u7ebf\u7a0b\u5728\u5bf9\u8c61\u4e0a\u7b49\u5f85\uff0c\u8fd9\u901a\u5e38\u610f\u5473\u7740\u7ebf\u7a0b\u7a7a\u95f2\uff0c\u53ef\u80fd\u5728\u7b49\u5f85\u4efb\u52a1\uff1b<br \/>\n\u5982\u679c Java \u5e94\u7528\u7a0b\u5e8f\u7684\u91cd\u8981\u7ebf\u7a0b\u82b1\u8d39\u5f88\u591a\u65f6\u95f4\u5728\u963b\u585e\u4e0a\uff0c\u8868\u660e\u5e94\u7528\u7684\u5173\u952e\u533a\u57df\u662f\u5355\u7ebf\u7a0b\u7684\uff0c\u662f\u4e2a\u74f6\u9888\u3002<br \/>\n\u82b1\u8d39\u65f6\u95f4\u8d8a\u591a\u7684\u4e8b\u4ef6\u8d8a\u53ef\u80fd\u662f\u74f6\u9888\u3002<\/p>\n<p>\u7eff\u8272\u90e8\u5206\u8868\u793a\u7ebf\u7a0b\u6ca1\u6709\u7761\u7720\u3001\u7b49\u5f85\u3001\u8bfb\u6216\u5199\u5957\u63a5\u5b57\uff0c\u4e5f\u6ca1\u6709\u88ab\u963b\u585e\u3002\u901a\u5e38\u8fd9\u662f\u7ebf\u7a0b\u5728\u5141\u8bb8\u5e94\u7528\u4ee3\u7801\u3002\u5982\u679c Java \u5e94\u7528\u7684\u91cd\u8981\u7ebf\u7a0b\u82b1\u8d39\u5927\u91cf\u65f6\u95f4\u800c\u6ca1\u6709\u751f\u6210\u4efb\u4f55\u5e94\u7528\u4e8b\u4ef6\uff0c\u90a3\u4e48\u5e94\u7528\u7684\u74f6\u9888\u53ef\u80fd\u4ee3\u7801\u6216 CPU \u81ea\u8eab\u3002<\/p>\n<p><strong>\u6ce8\u610f\uff1a<\/strong>\u5bf9\u4e8e\u5927\u591a\u6570 Java \u5e94\u7528\u4e8b\u4ef6\u7c7b\u578b\uff0c\u53ea\u6709\u8d85\u8fc7 20 ms \u7684\u4e8b\u4ef6\u5c06\u88ab\u8bb0\u5f55\uff08\u8fd9\u4e2a\u9600\u503c\u53ef\u4ee5\u5728\u542f\u52a8\u98de\u884c\u8bb0\u5f55\u65f6\u4fee\u6539\uff09\u3002\u6ca1\u6709\u8bb0\u5f55\u4e8b\u4ef6\u7684\u533a\u57df\u53ef\u80fd\u662f\u56e0\u4e3a\u5e94\u7528\u5728\u505a\u5927\u91cf\u7684\u77ed\u4efb\u52a1\uff0c\u4f8b\u5982\u8bfb\u5199\u6587\u4ef6\uff08\u6bcf\u6b21\u4e00\u5c0f\u90e8\u5206\uff09\u6216\u505a\u5f88\u77ed\u65f6\u95f4\u7684\u540c\u6b65\u3002<\/p>\n<p>\u4e8b\u4ef6\u9009\u9879\u5361\u6ca1\u6709\u663e\u793a GC \u548c GC \u662f\u5426\u53ef\u80fd\u6210\u4e3a\u74f6\u9888\u3002<\/p>\n<p><a name=\"Garbage-Collection-Performance\"><\/a><\/p>\n<h2>\u4e09\u3001GC \u6027\u80fd<\/h2>\n<p>\u8c03\u4f18 HotSpot \u5783\u573e\u6536\u96c6\u5668\u53ef\u4ee5\u5bf9\u6027\u80fd\u6709\u5f88\u5927\u5f71\u54cd\u3002\u66f4\u591a\u4fe1\u606f\u89c1<a href=\"http:\/\/docs.oracle.com\/javase\/8\/docs\/technotes\/guides\/vm\/gctuning\/index.html\">Garbage Collection Tuning Guide<\/a>\u3002<\/p>\n<p>\u542f\u52a8\u98de\u884c\u8bb0\u5f55\u65f6\u6700\u597d\u4e0d\u597d\u5305\u62ec\u5806\u7edf\u8ba1\uff0c\u56e0\u4e3a\u8fd9\u4f1a\u89e6\u53d1\u989d\u5916\u7684\u5e74\u8001\u4ee3\u6536\u96c6\u3002\u4e3a\u4e86\u5f97\u5230\u66f4\u597d\u7684\u62bd\u6837\uff0c\u8ba9\u8bb0\u5f55\u65f6\u95f4\u5c3d\u91cf\u957f\u3002<\/p>\n<p>\u9009\u62e9 \u201cMemory\u201d \u9009\u9879\u5361\u7136\u540e\u9009\u62e9\u201cGC Times\u201d\u5b50\u9009\u9879\u5361\u3002GC Times \u662f\u8c03\u67e5 GC \u6574\u4f53\u6027\u80fd\u5f71\u54cd\u7684\u5f88\u597d\u9009\u9879\u5361\u3002\u5728\u53f3\u4e0a\u89d2\uff0c\u770b\u201cAll Collections Pause Time\u201d\u533a\u57df\u7684\u201cAverage Sum of Pauses\u201d, \u201cMaximum Sum of Pauses\u201d, \u201cTotal Pause Time\u201d \u7684\u8bb0\u5f55\u3002\u201cSum of Pauses\u201d \u662f\u5e94\u7528\u5728 GC \u671f\u95f4\u6682\u505c\u7684\u6240\u6709\u65f6\u95f4\u3002\u5f88\u591a GC \u5728\u540e\u53f0\u505a\u5927\u90e8\u5206\u5de5\u4f5c\uff0c\u5728\u8fd9\u4e9b\u60c5\u51b5\u4e0b\uff0cGC \u7684\u957f\u5ea6\u4e0d\u8981\u7d27\uff0c\u8981\u7d27\u7684\u662f\u5e94\u7528\u5fc5\u987b\u505c\u6b62\u591a\u957f\u65f6\u95f4\u3002\u56e0\u6b64\u201cSum of Pauses\u201d\u662f\u5bf9 GC \u5f71\u54cd\u7684\u5f88\u597d\u8861\u91cf\u3002<\/p>\n<p>\u4e0b\u56fe\u5c55\u793a\u4e86 5 \u5206\u949f\u7684\u98de\u884c\u8bb0\u5f55\uff0c\u5728\u8fd9\u4e2a\u65f6\u95f4\u5185\uff0c\u6682\u505c\u7684\u5e73\u5747\u65f6\u95f4\u662f 16 ms\uff0c\u6700\u5927\u6682\u505c\u65f6\u95f4\u662f 49 ms\uff0c\u603b\u7684\u6682\u505c\u65f6\u95f4\u662f 2\u79d286\u6beb\u79d2\u3002<br \/>\n<img decoding=\"async\" src=\"\/\/coderbee.net\/wp-content\/uploads\/2015\/04\/jfr-gc.png\" alt=\"jfr-gc\" \/><\/p>\n<p>\u901a\u5e38\uff0cGC \u7684\u4e3b\u8981\u6027\u80fd\u95ee\u9898\u8981\u4e48\u5355\u6b21 GC \u82b1\u4e86\u5f88\u957f\u65f6\u95f4\uff0c\u8981\u4e48\u662f GC \u6682\u505c\u82b1\u4e86\u5f88\u591a\u65f6\u95f4\uff08\u603b\u7684GC\u6682\u505c\uff09\u3002<\/p>\n<p>\u5f53\u5355\u6b21 GC \u82b1\u4e86\u592a\u957f\u65f6\u95f4\u65f6\uff0c\u4f60\u53ef\u80fd\u9700\u8981\u6539\u53d8 GC \u7b56\u7565\u3002\u4e0d\u540c\u7684 GC \u6709\u4e0d\u540c\u7684\u6743\u8861\uff0c\u5728\u6682\u505c\u65f6\u95f4\u548c\u541e\u5410\u91cf\u6027\u80fd\u4e4b\u95f4\u3002\u66f4\u591a\u4fe1\u606f\u89c1<a href=\"http:\/\/docs.oracle.com\/javase\/8\/docs\/technotes\/guides\/vm\/gctuning\/ergonomics.html#sthref13\">Behavior-Based Tuning<\/a>\u3002<\/p>\n<p>\u4f8b\u5982\uff0c\u4f60\u53ef\u80fd\u9700\u8981\u4fee\u590d\u4f60\u7684\u5e94\u7528\u4ee5\u51cf\u5c11\u4f7f\u7528 finalizer \u548c\/\u6216 semi-references\u3002<\/p>\n<p>\u5f53\u5e94\u7528\u82b1\u4e86\u5f88\u591a\u65f6\u95f4\u5728\u6682\u505c\u4e0a\u65f6\uff0c\u6709\u591a\u79cd\u65b9\u6cd5\u53ef\u4ee5\u53d8\u901a\u3002<\/p>\n<p>\u4e00\u79cd\u65b9\u6cd5\u662f\u589e\u52a0 Java \u5806\u7684\u5927\u5c0f\u3002\u5728\u201cGarbage Collection\u201d\u5b50\u9009\u9879\u5361\u4f30\u8ba1\u5e94\u7528\u4f7f\u7528\u7684 Java \u5806\u5927\u5c0f\uff0c\u52a0\u5927 <code>Xms<\/code> \u548c <code>Xmx<\/code> \u7684\u503c\u3002Java \u5806\u8d8a\u5927\uff0cGC \u65f6\u95f4\u8d8a\u957f\u3002\u5c0f\u5fc3 Java \u5e94\u7528\u7684\u4efb\u4f55\u5185\u5b58\u6cc4\u9732\uff0c\u56e0\u4e3a\u90a3\u53ef\u80fd\u5bfc\u81f4\u66f4\u9891\u7e41\u7684 GC \u76f4\u81f3\u629b\u51fa <code>OutOfMemoryError<\/code>\u3002\u66f4\u591a\u4fe1\u606f\u89c1<a href=\"http:\/\/docs.oracle.com\/javase\/8\/docs\/technotes\/guides\/troubleshoot\/memleaks001.html#CIHCAEIH\">Debug a Memory Leak Using Java Flight Recorder<\/a>\u3002<\/p>\n<p>\u53e6\u4e00\u79cd\u65b9\u6cd5\uff0c\u4e3a\u4e86\u51cf\u5c11 GC \u6b21\u6570\uff0c\u5206\u914d\u66f4\u5c11\u7684\u4e34\u65f6\u5bf9\u8c61\u3002\u5728\u201cAllocation\u201d\u9009\u9879\u5361\uff0c\u67e5\u770b\u5728\u8bb0\u5f55\u8fc7\u7a0b\u4e2d\u5df2\u5206\u914d\u4e86\u591a\u5c11\u5185\u5b58\u3002\u5c0f\u5bf9\u8c61\u662f\u5728 TLAB \u5185\u5206\u914d\uff0c\u5927\u5bf9\u8c61\u5728 TLAB \u5916\u5206\u914d\u3002\u7ecf\u5e38\uff0c\u4e3b\u8981\u7684\u5206\u914d\u53d1\u751f\u5728 TLAB \u5185\u3002<\/p>\n<p>\u6700\u540e\u4f46\u4e0d\u662f\u6700\u5c11\u7684\u51cf\u5c11 GC \u9700\u8981\u7684\u65b9\u6cd5\u662f\u51cf\u5c11\u5206\u914d\u9891\u7387\u3002\u9009\u62e9\u201cAlloc in new TLAB\u201d\u9009\u9879\u5361\uff0c\u7136\u540e\u9009\u62e9\u201cAllocations\u201d\u9009\u9879\u5361\uff0c\u67e5\u770b\u5206\u914d\u7684\u5927\u5c0f\u548c\u6709\u6700\u591a\u5185\u5b58\u538b\u529b\u7684\u6808\u8f68\u8ff9\u3002\u4f60\u53ef\u4ee5\u6309\u7c7b\u67e5\u770b\uff0c\u4e5f\u53ef\u4ee5\u9009\u62e9\u201cAllocation by Thread\u201d\u6765\u770b\u54ea\u4e2a\u7ebf\u7a0b\u6d88\u8017\u4e86\u6700\u591a\u5206\u914d\u3002<\/p>\n<p>\u66f4\u591a\u5173\u4e8e JFR Allocation \u9009\u9879\u5361\u7684\u7ec6\u8282\u89c1 <a href=\"http:\/\/docs.oracle.com\/javase\/8\/docs\/technotes\/guides\/troubleshoot\/tooldescr005.html#BABBBBIC\">Inspect a Flight Recording<\/a>\u3002<\/p>\n<p>\u5176\u4ed6\u7684\u4e00\u4e9b\u8bbe\u7f6e\u53ef\u80fd\u4e5f\u589e\u52a0\u5e94\u7528\u7684 GC \u6027\u80fd\u3002 <a href=\"http:\/\/docs.oracle.com\/javase\/8\/docs\/technotes\/guides\/vm\/gctuning\/index.html\">Garbage Collection Tuning Guide<\/a> \u7ae0\u8282\u5927\u90e8\u5206\u90fd\u662f\u8ba8\u8bba GC \u6027\u80fd\u7684\u3002<\/p>\n<p><a name=\"Synchronization-Performance\"><\/a><\/p>\n<h2>\u56db\u3001\u540c\u6b65\u6027\u80fd<\/h2>\n<p>\u4e3a\u4e86\u8c03\u8bd5 Java \u5e94\u7528\u7684\u540c\u6b65\u95ee\u9898\uff0c\u6216\u8005\u8bf4\u662f\u5e94\u7528\u7ebf\u7a0b\u5728\u54ea\u91cc\u82b1\u4e86\u6700\u591a\u7684\u65f6\u95f4\u6765\u8fdb\u5165\u76d1\u89c6\u5668\uff0c\u67e5\u770b\u201d\u7ebf\u7a0b\u201c\u9009\u9879\u5361\u7ec4\u7684 \u201c\u4e89\u7528\u201d\u9009\u9879\u5361\u3002\u770b\u770b\u54ea\u4e9b\u9501\u4e0a\u7684\u7ade\u4e89\u6700\u591a\u548c \u7b49\u5f85\u83b7\u5f97\u9501\u7684\u7ebf\u7a0b\u7684\u6808\u8f68\u8ff9\u3002\u5982\u4e0b\u56fe\uff1a<br \/>\n<img decoding=\"async\" src=\"\/\/coderbee.net\/wp-content\/uploads\/2015\/04\/jfr-synchronization.png\" alt=\"jfr-synchronization\" \/><\/p>\n<p>\u4e0a\u56fe\u7684\u8303\u56f4\u9009\u62e9\u8ba9\u4f60\u53ef\u4ee5\u770b\u5230\u4e8b\u4ef6\u5728\u54ea\u91cc\u53d1\u751f\u3002\u5728\u9009\u4e2d\u65f6\u95f4\u8303\u56f4\u5185\u653e\u5927\u8303\u56f4\u9009\u62e9\u5668\u6765\u67e5\u770b\u7ade\u4e89\u4e8b\u4ef6\u3002<\/p>\n<p>\u5178\u578b\u5730\uff0c\u67e5\u627e\u4f60\u4e0d\u8ba4\u4e3a\u662f\u95ee\u9898\u7684\u7ade\u4e89\u53ef\u80fd\u662f\u4e2a\u95ee\u9898\u3002\u6709\u7684\u5e94\u7528\uff0c\u65e5\u5fd7\u662f\u4e0d\u88ab\u8ba4\u4e3a\u662f\u5e94\u7528\u74f6\u9888\u7684\u5e38\u89c1\u533a\u57df\u3002<\/p>\n<p>\u5f53\u4f60\u7a0b\u5e8f\u66f4\u65b0\u6216\u5e94\u7528\u7684\u4efb\u4f55\u65f6\u95f4\u770b\u5230\u6027\u80fd\u9000\u5316\uff0c\u5728\u4e8b\u60c5\u8fd8\u597d\u7684\u60c5\u51b5\u4e0b\u83b7\u5f97\u4e00\u4e2a\u8bb0\u5f55\uff0c\u5728\u4e8b\u60c5\u770b\u8d77\u6765\u4e0d\u597d\u65f6\u83b7\u53d6\u53e6\u4e00\u4e2a\u8bb0\u5f55\uff08\uff0c\u505a\u5bf9\u6bd4\uff09\u3002<\/p>\n<p><strong>\u6ce8\u610f\uff1a<\/strong>\u5728\u8303\u56f4\u9009\u62e9\u5668\u91cc\u663e\u793a\u7684\u4e8b\u4ef6\u4e0d\u662f\u6240\u6709\u7684\u540c\u6b65\u4e8b\u4ef6\u3002\u9ed8\u8ba4\u5730\uff0c\u7ade\u4e89\u4e8b\u4ef6\u7684\u6301\u7eed\u65f6\u95f4\u8d85\u8fc7 20 ms \u624d\u4f1a\u88ab\u8bb0\u5f55\uff08\u8fd9\u4e2a\u9600\u503c\u5728\u5f00\u542f\u8bb0\u5f55\u65f6\u53ef\u4ee5\u4fee\u6539\uff09\u3002\u7f29\u77ed\u8fd9\u4e2a\u9600\u503c\u4f1a\u5f97\u5230\u66f4\u591a\u7684\u4e8b\u4ef6\uff0c\u4e5f\u6f5c\u5728\u5730\u5e26\u6765\u66f4\u591a\u7684\u5f00\u9500\u3002\u5982\u679c\u4f60\u8ba4\u4e3a\u7ade\u4e89\u662f\u4e2a\u95ee\u9898\uff0c\u4f60\u53ef\u4ee5\u7f29\u77ed\u8bb0\u5f55\u7684\u65f6\u95f4\uff0c\u8bbe\u7f6e\u5f88\u5c0f\u7684\u9600\u503c\uff08\u4ec5\u4ec5\u51e0\u6beb\u79d2\uff09\u3002\u5f53\u8fd9\u4e9b\u5728\u5b58\u6d3b\u5e94\u7528\u4e0a\u5b8c\u6210\u65f6\uff0c\u786e\u4fdd\u8bb0\u5f55\u65f6\u95f4\u5f88\u77ed\u5e76\u76d1\u89c6\u6027\u80fd\u5f00\u9500\u3002<\/p>\n<p><a name=\"I\/O-Performance\"><\/a><\/p>\n<h2>\u4e94\u3001I\/O \u6027\u80fd<\/h2>\n<p>\u5f53 Java \u5e94\u7528\u82b1\u4e86\u5927\u91cf\u65f6\u95f4\u5728\u8bfb\u5199\u5957\u63a5\u5b57\u6216\u6587\u4ef6\u4e0a\u65f6\uff0c\u90a3\u4e48 I\/O \u6216\u7f51\u7edc\u53ef\u80fd\u662f\u74f6\u9888\u3002<br \/>\n<img decoding=\"async\" src=\"\/\/coderbee.net\/wp-content\/uploads\/2015\/04\/jfr-io.png\" alt=\"jfr-io\" \/><\/p>\n<p>\u4e0a\u56fe\u663e\u793a\u4e86\u5e94\u7528\u6709 100 \u4e2a\u5bf9\u8fdc\u7a0b\u5730\u5740 <code>198.51.100.0<\/code> \u7684\u8bfb\u64cd\u4f5c\u3002\u8bfb\u53d6\u7684\u603b\u5b57\u8282\u6570\u662f 356 \u5b57\u8282\uff0c\u7528\u4e8e\u7b49\u5f85\u7684\u603b\u65f6\u95f4\u662f 1 \u5206 57 \u79d2\u3002\u9009\u62e9\u5de6\u4e0a\u89d2\u7684 &#8220;By Event&#8221; \u9009\u9879\u5361\u67e5\u770b\u6bcf\u4e2a\u4e8b\u4ef6\u6765\u5206\u6790\u82b1\u8d39\u7684\u65f6\u95f4\u548c\u8bfb\u53d6\u7684\u6570\u636e\u3002<\/p>\n<p>\u6587\u4ef6\u6216\u7f51\u7edc I\/O \u95ee\u9898\u7684\u8bca\u65ad\u7528\u540c\u6837\u7684\u65b9\u5f0f\u3002<\/p>\n<p>\u5728 I\/O \u91cc\u7684\u6240\u6709\u9009\u9879\u5361\u9ed8\u8ba4\u663e\u793a\u6301\u7eed\u65f6\u95f4\u8d85\u8fc7 20ms \u7684\u4e8b\u4ef6\uff0c\u53ef\u4ee5\u5728\u542f\u52a8\u65f6\u8c03\u6574\u9600\u503c\u3002<\/p>\n<p><a name=\"Code-Execution-Performance\"><\/a><\/p>\n<h2>\u516d\u3001\u4ee3\u7801\u6267\u884c\u6027\u80fd<\/h2>\n<p>\u5f53\u6ca1\u6709\u5f88\u591a Java \u5e94\u7528\u4e8b\u4ef6\u65f6\uff0c\u4e3b\u8981\u7684\u74f6\u9888\u53ef\u80fd\u5728\u4f60\u7684\u5e94\u7528\u8fd0\u884c\u4ee3\u7801\u4e0a\u3002\u9996\u5148\uff0c\u5728\u201cthe Threads\u201d\u9009\u9879\u5361\u9009\u62e9\u201cOverview\u201d\u9009\u9879\u5361\uff0c\u770b \u201cCPU Usage Over Time\u201d\u3002\u8fd9\u663e\u793a\u4e86\u8bb0\u5f55\u4e0b\u7684 JVM CPU \u4f7f\u7528\u60c5\u51b5\u548c\u673a\u5668\u7684\u603b\u7684 CPU \u4f7f\u7528\u60c5\u51b5\u3002\u5982\u679c JVM CPU \u4f7f\u7528\u4f4e\uff0c\u4f46\u673a\u5668\u7684 CPU \u4f7f\u7528\u9ad8\uff0c\u8fd9\u610f\u5473\u7740\u5176\u4ed6\u5e94\u7528\u5360\u7528\u4e86\u5f88\u591a CPU\u3002\u7136\u540e\u5728\u201cSystem\u201d\u9009\u9879\u5361\u7ec4\u7684\u201cProcesses\u201d\u9009\u9879\u5361\u67e5\u770b\u7cfb\u7edf\u91cc\u5176\u4ed6\u5e94\u7528\u3002\u7136\u800c\uff0c\u4f60\u53ef\u80fd\u770b\u4e0d\u5230\u5b83\u4eec\u7684 CPU \u4f7f\u7528\u60c5\u51b5\uff0c\u6240\u4ee5\uff0c\u901a\u5e38\u7528 OS \u7684\u5de5\u5177\u5982 top \u6216\u4efb\u52a1\u7ba1\u7406\u5668\u6765\u627e\u51fa\u4f7f\u7528\u4e86\u5f88\u591a CPU \u7684\u8fdb\u7a0b\u3002<\/p>\n<p>\u9009\u62e9\u201cCode\u201d\u9009\u9879\u5361\u7ec4\uff0c\u67e5\u770b\u201cHot Threads\u201d\u9009\u9879\u5361\u4ee5\u9632\u4f60\u7684\u5e94\u7528\u4f7f\u7528\u4e86\u5f88\u591a CPU \u65f6\u95f4\u3002\u8fd9\u4e2a\u9009\u9879\u5361\u663e\u793a\u4e86\u4f7f\u7528 CPU \u65f6\u95f4\u6700\u591a\u7684\u7ebf\u7a0b\u3002\u7136\u800c\uff0c\u8fd9\u4e2a\u4fe1\u606f\u662f\u57fa\u4e8e\u65b9\u6cd5\u62bd\u6837\u7684\uff0c\u56e0\u6b64\u8fd9\u53ef\u80fd\u4e0d\u662f\u767e\u5206\u767e\u7cbe\u786e\u7684\uff0c\u5982\u679c\u62bd\u6837\u6570\u91cf\u4f4e\u3002\u5f53 JFR \u8fd0\u884c\u65f6\uff0cJVM \u62bd\u6837\u7ebf\u7a0b\u3002\u9ed8\u8ba4\u5730\uff0c\u4e00\u4e2a\u6301\u7eed\u8bb0\u5f55\u53ea\u8fdb\u884c\u65b9\u6cd5\u62bd\u6837\uff0c\u800c\u4e00\u4e2a\u6027\u80fd\u8bb0\u5f55\u4f1a\u5c3d\u53ef\u80fd\u591a\u505a\u3002\u65b9\u6cd5\u62bd\u6837\u53ea\u6536\u96c6\u5b9e\u9645\u8fd0\u884c\u4ee3\u7801\u7684\u7ebf\u7a0b\u7684\u6570\u636e\u3002\u8fd9\u4e9b\u7b49\u5f85 I\/O\u3001\u7761\u7720\u3001\u7b49\u5f85\u9501\u7b49\u662f\u4e0d\u4f1a\u88ab\u62bd\u6837\u7684\u3002\u56e0\u6b64\uff0c\u56e0\u6b64\uff0c\u6709\u5f88\u591a\u65b9\u6cd5\u62bd\u6837\u7684\u7ebf\u7a0b\u662f\u4f7f\u7528 CPU \u65f6\u95f4\u6700\u591a\u7684\uff1b\u7136\u800c\uff0c\u6bcf\u4e2a\u7ebf\u7a0b\u4f7f\u7528\u4e86\u591a\u5c11 CPU \u662f\u4e0d\u77e5\u7684\u3002<\/p>\n<p>\u201cCode\u201d\u9009\u9879\u5361\u7ec4\u91cc\u7684\u201cHot Methods\u201d\u9009\u9879\u5361\u5e2e\u52a9\u627e\u51fa\u5e94\u7528\u5728\u54ea\u91cc\u82b1\u4e86\u6700\u591a\u7684\u6267\u884c\u65f6\u95f4\u3002\u8fd9\u4e2a\u9009\u9879\u5361\u663e\u793a\u4e86\u6808\u91cc\u6309\u9876\u5c42\u65b9\u6cd5\u5206\u7ec4\u7684\u62bd\u6837\u3002\u7528\u201cCall Tree\u201d\u9009\u9879\u5361\uff0c\u4ece\u6808\u8f68\u8ff9\u7684\u6700\u4f4e\u7aef\u65b9\u6cd5\u5f00\u59cb\uff0c\u7136\u540e\u5411\u4e0a\u3002<br \/>\n<img decoding=\"async\" src=\"\/\/coderbee.net\/wp-content\/uploads\/2015\/04\/jfr-stack-trace.png\" alt=\"jfr-stack-trace\" \/><\/p>\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>\u5185\u5bb9\u76ee\u5f55 JFR \u6982\u89c8 \u627e\u51fa\u74f6\u9888 GC \u6027\u80fd \u540c\u6b65\u6027\u80fd I\/O \u6027\u80fd \u4ee3\u7801\u6267\u884c\u6027 &hellip; <a href=\"https:\/\/coderbee.net\/index.php\/jvm\/20150408\/1201\">\u7ee7\u7eed\u9605\u8bfb <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[96],"tags":[213,233],"_links":{"self":[{"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/posts\/1201"}],"collection":[{"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/comments?post=1201"}],"version-history":[{"count":4,"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/posts\/1201\/revisions"}],"predecessor-version":[{"id":1217,"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/posts\/1201\/revisions\/1217"}],"wp:attachment":[{"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/media?parent=1201"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/categories?post=1201"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/tags?post=1201"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}