{"id":320,"date":"2017-08-01T16:14:25","date_gmt":"2017-08-01T08:14:25","guid":{"rendered":"https:\/\/blog.jsjs.org\/?p=320"},"modified":"2017-08-01T16:14:25","modified_gmt":"2017-08-01T08:14:25","slug":"%e6%8e%a2%e7%a7%98java%e8%99%9a%e6%8b%9f%e6%9c%ba-%e5%86%85%e5%ad%98%e7%ae%a1%e7%90%86%e4%b8%8e%e5%9e%83%e5%9c%be%e5%9b%9e%e6%94%b6","status":"publish","type":"post","link":"https:\/\/blog.jsjs.org\/?p=320","title":{"rendered":"\u63a2\u79d8Java\u865a\u62df\u673a\u2014\u2014\u5185\u5b58\u7ba1\u7406\u4e0e\u5783\u573e\u56de\u6536"},"content":{"rendered":"<p>\u672c\u6587\u4e3b\u8981\u662f\u57fa\u4e8eSun JDK 1.6 Garbage Collector\uff08\u4f5c\u8005\uff1a\u6bd5\u7384\uff09\u7684\u6574\u7406\u4e0e\u603b\u7ed3\uff0c\u539f\u6587\u8bf7\u8bfb\u8005\u5728\u7f51\u4e0a\u641c\u7d22\u3002<\/p>\n<p><strong>1\u3001Java\u865a\u62df\u673a\u8fd0\u884c\u65f6\u7684\u6570\u636e\u533a<\/strong><\/p>\n<p><a href=\"http:\/\/www.blogjava.net\/images\/blogjava_net\/chhbjh\/Windows-Live-Writer\/2d08114b62d1_AA6A\/image_5.png\"><img loading=\"lazy\" decoding=\"async\" title=\"image\" src=\"http:\/\/www.blogjava.net\/images\/blogjava_net\/chhbjh\/Windows-Live-Writer\/2d08114b62d1_AA6A\/image_thumb_1.png\" alt=\"image\" width=\"475\" height=\"398\" border=\"0\" \/><\/a><\/p>\n<p><strong>2\u3001\u5e38\u7528\u7684\u5185\u5b58\u533a\u57df\u8c03\u8282\u53c2\u6570<\/strong><\/p>\n<p><strong>-Xms<\/strong>\uff1a\u521d\u59cb\u5806\u5927\u5c0f\uff0c\u9ed8\u8ba4\u4e3a\u7269\u7406\u5185\u5b58\u76841\/64(&lt;1GB)\uff1b\u9ed8\u8ba4(MinHeapFreeRatio\u53c2\u6570\u53ef\u4ee5\u8c03\u6574)\u7a7a\u4f59\u5806\u5185\u5b58\u5c0f\u4e8e40%\u65f6\uff0cJVM\u5c31\u4f1a\u589e\u5927\u5806\u76f4\u5230-Xmx\u7684\u6700\u5927\u9650\u5236<\/p>\n<p><strong>-Xmx<\/strong>\uff1a\u6700\u5927\u5806\u5927\u5c0f\uff0c\u9ed8\u8ba4(MaxHeapFreeRatio\u53c2\u6570\u53ef\u4ee5\u8c03\u6574)\u7a7a\u4f59\u5806\u5185\u5b58\u5927\u4e8e70%\u65f6\uff0cJVM\u4f1a\u51cf\u5c11\u5806\u76f4\u5230 -Xms\u7684\u6700\u5c0f\u9650\u5236<\/p>\n<p><strong>-Xmn<\/strong>\uff1a\u65b0\u751f\u4ee3\u7684\u5185\u5b58\u7a7a\u95f4\u5927\u5c0f\uff0c<strong>\u6ce8\u610f<\/strong>\uff1a\u6b64\u5904\u7684\u5927\u5c0f\u662f\uff08eden+ 2 survivor space)\u3002\u4e0ejmap -heap\u4e2d\u663e\u793a\u7684New gen\u662f\u4e0d\u540c\u7684\u3002\u6574\u4e2a\u5806\u5927\u5c0f=\u65b0\u751f\u4ee3\u5927\u5c0f + \u8001\u751f\u4ee3\u5927\u5c0f + \u6c38\u4e45\u4ee3\u5927\u5c0f\u3002<br \/>\n\u5728\u4fdd\u8bc1\u5806\u5927\u5c0f\u4e0d\u53d8\u7684\u60c5\u51b5\u4e0b\uff0c\u589e\u5927\u65b0\u751f\u4ee3\u540e,\u5c06\u4f1a\u51cf\u5c0f\u8001\u751f\u4ee3\u5927\u5c0f\u3002\u6b64\u503c\u5bf9\u7cfb\u7edf\u6027\u80fd\u5f71\u54cd\u8f83\u5927,Sun\u5b98\u65b9\u63a8\u8350\u914d\u7f6e\u4e3a\u6574\u4e2a\u5806\u76843\/8\u3002<\/p>\n<p><strong>-XX:SurvivorRatio<\/strong>\uff1a\u65b0\u751f\u4ee3\u4e2dEden\u533a\u57df\u4e0eSurvivor\u533a\u57df\u7684\u5bb9\u91cf\u6bd4\u503c\uff0c\u9ed8\u8ba4\u503c\u4e3a8\u3002\u4e24\u4e2aSurvivor\u533a\u4e0e\u4e00\u4e2aEden\u533a\u7684\u6bd4\u503c\u4e3a2:8,\u4e00\u4e2aSurvivor\u533a\u5360\u6574\u4e2a\u5e74\u8f7b\u4ee3\u76841\/10\u3002<\/p>\n<p><strong>-Xss<\/strong>\uff1a\u6bcf\u4e2a\u7ebf\u7a0b\u7684\u5806\u6808\u5927\u5c0f\u3002JDK5.0\u4ee5\u540e\u6bcf\u4e2a\u7ebf\u7a0b\u5806\u6808\u5927\u5c0f\u4e3a1M,\u4ee5\u524d\u6bcf\u4e2a\u7ebf\u7a0b\u5806\u6808\u5927\u5c0f\u4e3a256K\u3002\u5e94\u6839\u636e\u5e94\u7528\u7684\u7ebf\u7a0b\u6240\u9700\u5185\u5b58\u5927\u5c0f\u8fdb\u884c\u9002\u5f53\u8c03\u6574\u3002\u5728\u76f8\u540c\u7269\u7406\u5185\u5b58\u4e0b,\u51cf\u5c0f\u8fd9\u4e2a\u503c\u80fd\u751f\u6210\u66f4\u591a\u7684\u7ebf\u7a0b\u3002\u4f46\u662f\u64cd\u4f5c\u7cfb\u7edf\u5bf9\u4e00\u4e2a\u8fdb\u7a0b\u5185\u7684\u7ebf\u7a0b\u6570\u8fd8\u662f\u6709\u9650\u5236\u7684\uff0c\u4e0d\u80fd\u65e0\u9650\u751f\u6210\uff0c\u7ecf\u9a8c\u503c\u57283000~5000\u5de6\u53f3\u3002\u4e00\u822c\u5c0f\u7684\u5e94\u7528\uff0c \u5982\u679c\u6808\u4e0d\u662f\u5f88\u6df1\uff0c \u5e94\u8be5\u662f128k\u591f\u7528\u7684\uff0c\u5927\u7684\u5e94\u7528\u5efa\u8bae\u4f7f\u7528256k\u3002\u8fd9\u4e2a\u9009\u9879\u5bf9\u6027\u80fd\u5f71\u54cd\u6bd4\u8f83\u5927\uff0c\u9700\u8981\u4e25\u683c\u7684\u6d4b\u8bd5\u3002\u548cthreadstacksize\u9009\u9879\u89e3\u91ca\u5f88\u7c7b\u4f3c,\u5b98\u65b9\u6587\u6863\u4f3c\u4e4e\u6ca1\u6709\u89e3\u91ca,\u5728\u8bba\u575b\u4e2d\u6709\u8fd9\u6837\u4e00\u53e5\u8bdd:&#8221;-Xss is translated in a VM flag named ThreadStackSize\u201d\u4e00\u822c\u8bbe\u7f6e\u8fd9\u4e2a\u503c\u5c31\u53ef\u4ee5\u4e86\u3002<\/p>\n<p><strong>-XX:PermSize<\/strong>\uff1a\u8bbe\u7f6e\u6c38\u4e45\u4ee3(perm gen)\u521d\u59cb\u503c\u3002\u9ed8\u8ba4\u503c\u4e3a\u7269\u7406\u5185\u5b58\u76841\/64\u3002<\/p>\n<p><strong>-XX:MaxPermSize<\/strong>\uff1a\u8bbe\u7f6e\u6301\u4e45\u4ee3\u6700\u5927\u503c\u3002\u7269\u7406\u5185\u5b58\u76841\/4\u3002<\/p>\n<p><strong>3\u3001\u5185\u5b58\u5206\u914d\u65b9\u6cd5<\/strong><\/p>\n<p>1\uff09\u5806\u4e0a\u5206\u914d\u00a0\u00a0 2\uff09\u6808\u4e0a\u5206\u914d\u00a0 3\uff09\u5806\u5916\u5206\u914d\uff08DirectByteBuffer\u6216\u76f4\u63a5\u4f7f\u7528Unsafe.allocateMemory,\u4f46\u4e0d\u63a8\u8350\u8fd9\u79cd\u65b9\u5f0f\uff09<\/p>\n<p><strong>4\u3001\u76d1\u63a7\u65b9\u6cd5<\/strong><\/p>\n<p>1\uff09\u7cfb\u7edf\u7a0b\u5e8f\u8fd0\u884c\u65f6\u53ef\u901a\u8fc7jstat \u2013gcutil\u6765\u67e5\u770b\u5806\u4e2d\u5404\u4e2a\u5185\u5b58\u533a\u57df\u7684\u53d8\u5316\u4ee5\u53caGC\u7684\u5de5\u4f5c\u72b6\u6001\uff1b<br \/>\n2\uff09\u542f\u52a8\u65f6\u53ef\u6dfb\u52a0-XX:+PrintGCDetails\u00a0 \u2013Xloggc:&lt;file&gt;\u8f93\u51fa\u5230\u65e5\u5fd7\u6587\u4ef6\u6765\u67e5\u770bGC\u7684\u72b6\u51b5\uff1b<br \/>\n3\uff09jmap \u2013heap\u53ef\u7528\u4e8e\u67e5\u770b\u5404\u4e2a\u5185\u5b58\u7a7a\u95f4\u7684\u5927\u5c0f\uff1b<\/p>\n<p><strong>5\uff09\u65ad\u4ee3\u6cd5\u53ef\u7528GC\u6c47\u603b<\/strong><\/p>\n<p><a href=\"http:\/\/www.blogjava.net\/images\/blogjava_net\/chhbjh\/Windows-Live-Writer\/2d08114b62d1_AA6A\/image_3.png\"><img loading=\"lazy\" decoding=\"async\" title=\"image\" src=\"http:\/\/www.blogjava.net\/images\/blogjava_net\/chhbjh\/Windows-Live-Writer\/2d08114b62d1_AA6A\/image_thumb.png\" alt=\"image\" width=\"581\" height=\"460\" border=\"0\" \/><\/a><\/p>\n<p>\u4e00\u3001\u65b0\u751f\u4ee3\u53ef\u7528GC<\/p>\n<p>1\uff09\u4e32\u884cGC(Serial Copying)\uff1aclient\u6a21\u5f0f\u4e0b\u9ed8\u8ba4GC\u65b9\u5f0f\uff0c\u4e5f\u53ef\u901a\u8fc7-XX:+UseSerialGC\u6765\u5f3a\u5236\u6307\u5b9a\uff1b\u9ed8\u8ba4\u60c5\u51b5\u4e0b eden\u3001s0\u3001s1\u7684\u5927\u5c0f\u901a\u8fc7-XX:SurvivorRatio\u6765\u63a7\u5236\uff0c\u9ed8\u8ba4\u4e3a8\uff0c\u542b\u4e49<br \/>\n\u4e3aeden:s0\u7684\u6bd4\u4f8b\uff0c\u542f\u52a8\u540e\u53ef\u901a\u8fc7jmap \u2013heap [pid]\u6765\u67e5\u770b\u3002<\/p>\n<p>\u9ed8\u8ba4\u60c5\u51b5\u4e0b\uff0c\u4ec5\u5728TLAB\u6216eden\u4e0a\u5206\u914d\uff0c\u53ea\u6709\u4e24\u79cd\u60c5\u51b5\u4e0b\u4f1a\u5728\u8001\u751f\u4ee3\u5206\u914d\uff1a<br \/>\n1\u3001\u9700\u8981\u5206\u914d\u7684\u5185\u5b58\u5927\u5c0f\u8d85\u8fc7eden space\u5927\u5c0f\uff1b<br \/>\n2\u3001\u5728\u914d\u7f6e\u4e86PretenureSizeThreshold\u7684\u60c5\u51b5\u4e0b\uff0c\u5bf9\u8c61\u5927\u5c0f\u5927\u4e8e\u6b64\u503c\u3002<\/p>\n<p>\u9ed8\u8ba4\u60c5\u51b5\u4e0b\uff0c\u89e6\u53d1Minor GC\u65f6\uff1a<br \/>\n\u4e4b\u524dMinor GC\u664b\u7ea7\u5230old\u7684\u5e73\u5747\u5927\u5c0f &lt; \u8001\u751f\u4ee3\u7684\u5269\u4f59\u7a7a\u95f4 &lt; eden+from Survivor\u7684\u4f7f\u7528\u7a7a\u95f4\u3002\u5f53HandlePromotionFailure\u4e3atrue\uff0c\u5219\u4ec5\u89e6\u53d1minor gc\uff1b\u5982\u4e3afalse\uff0c\u5219\u89e6\u53d1full GC\u3002<\/p>\n<p>\u9ed8\u8ba4\u60c5\u51b5\u4e0b\uff0c\u65b0\u751f\u4ee3\u5bf9\u8c61\u664b\u5347\u5230\u8001\u751f\u4ee3\u7684\u89c4\u5219\uff1a<\/p>\n<p>1\u3001\u7ecf\u5386\u591a\u6b21minor gc\u4ecd\u5b58\u6d3b\u7684\u5bf9\u8c61\uff0c\u53ef\u901a\u8fc7\u4ee5\u4e0b\u53c2\u6570\u6765\u63a7\u5236\uff1a\u4ee5MaxTenuringThreshold\u503c\u4e3a\u51c6\uff0c\u9ed8\u8ba4\u4e3a15\u3002<br \/>\n2\u3001to space\u653e\u4e0d\u4e0b\u7684\uff0c\u76f4\u63a5\u653e\u5165\u8001\u751f\u4ee3\uff1b<\/p>\n<p>2\uff09\u5e76\u884cGC\uff08ParNew\uff09\uff1aCMS GC\u65f6\u9ed8\u8ba4\u91c7\u7528\uff0c\u4e5f\u53ef\u91c7\u7528-XX:+UseParNewGC\u5f3a\u5236\u6307\u5b9a\uff1b\u5783\u573e\u56de\u6536\u7684\u65f6\u5019\u91c7\u7528\u591a\u7ebf\u7a0b\u7684\u65b9\u5f0f\u3002<\/p>\n<p>3\uff09\u5e76\u884c\u56de\u6536GC(Parallel Scavenge)\uff1aserver\u6a21\u5f0f\u4e0b\u9ed8\u8ba4\u7684GC\u65b9\u5f0f\uff0c\u4e5f\u53ef\u91c7\u7528-XX:+UseParallelGC\u5f3a\u5236\u6307\u5b9a\uff1beden\u3001s0\u3001s1\u7684\u5927\u5c0f\u53ef\u901a\u8fc7-XX:SurvivorRatio\u6765\u63a7\u5236\uff0c\u4f46\u9ed8\u8ba4\u60c5\u51b5\u4e0b<br \/>\n\u4ee5-XX:InitialSurivivorRatio\u4e3a\u51c6\uff0c\u6b64\u503c\u9ed8\u8ba4\u4e3a8\uff0c<strong>\u4ee3\u8868\u7684\u4e3a\u65b0\u751f\u4ee3\u5927\u5c0f : s0<\/strong>\uff0c\u8fd9\u70b9\u8981\u7279\u522b\u6ce8\u610f\u3002<\/p>\n<p>\u9ed8\u8ba4\u60c5\u51b5\u4e0b\uff0c\u5f53TLAB\u3001eden\u4e0a\u5206\u914d\u90fd\u5931\u8d25\u65f6\uff0c\u5224\u65ad\u9700\u8981\u5206\u914d\u7684\u5185\u5b58\u5927\u5c0f\u662f\u5426 &gt;= eden space\u7684\u4e00\u534a\u5927\u5c0f\uff0c\u5982\u662f\u5c31\u76f4\u63a5\u5728\u8001\u751f\u4ee3\u4e0a\u5206\u914d\uff1b<\/p>\n<p>\u9ed8\u8ba4\u60c5\u51b5\u4e0b\u7684\u5783\u573e\u56de\u6536\u89c4\u5219\uff1a<\/p>\n<p>1\u3001\u5728\u56de\u6536\u524dPS GC\u4f1a\u5148\u68c0\u6d4b\u4e4b\u524d\u6bcf\u6b21PS GC\u65f6\uff0c\u664b\u5347\u5230\u8001\u751f\u4ee3\u7684\u5e73\u5747\u5927\u5c0f\u662f\u5426\u5927\u4e8e\u8001\u751f\u4ee3\u7684\u5269\u4f59\u7a7a\u95f4\uff0c\u5982\u5927\u4e8e\u5219\u76f4\u63a5\u89e6\u53d1full GC\uff1b<br \/>\n2\u3001\u5728\u56de\u6536\u540e\uff0c\u4e5f\u4f1a\u6309\u7167\u4e0a\u9762\u7684\u89c4\u5219\u8fdb\u884c\u68c0\u6d4b\u3002<\/p>\n<p>\u9ed8\u8ba4\u60c5\u51b5\u4e0b\u7684\u65b0\u751f\u4ee3\u5bf9\u8c61\u664b\u5347\u5230\u8001\u751f\u4ee3\u7684\u89c4\u5219\uff1a<br \/>\n1\u3001\u7ecf\u5386\u591a\u6b21minor gc\u4ecd\u5b58\u6d3b\u7684\u5bf9\u8c61\uff0c\u53ef\u901a\u8fc7\u4ee5\u4e0b\u53c2\u6570\u6765\u63a7\u5236\uff1aAlwaysTenure\uff0c\u9ed8\u8ba4false\uff0c\u8868\u793a\u53ea\u8981minor GC\u65f6\u5b58\u6d3b\uff0c\u5c31\u664b\u5347\u5230\u8001\u751f\u4ee3\uff1bNeverTenure\uff0c\u9ed8\u8ba4false\uff0c\u8868\u793a\u6c38\u4e0d\u664b\u5347\u5230\u8001\u751f\u4ee3\uff1b\u4e0a\u9762\u4e24\u4e2a\u90fd\u6ca1\u8bbe\u7f6e\u7684\u60c5\u51b4\u4e0b\uff0c\u5982UseAdaptiveSizePolicy\uff0c\u542f\u52a8\u65f6\u4ee5InitialTenuringThreshold\u503c\u4f5c\u4e3a\u5b58\u6d3b\u6b21\u6570\u7684\u9608\u503c\uff0c\u5728\u6bcf\u6b21ps gc\u540e\u4f1a\u52a8\u6001\u8c03\u6574\uff0c\u5982\u4e0d\u4f7f\u7528UseAdaptiveSizePolicy\uff0c\u5219\u4ee5MaxTenuringThreshold\u4e3a\u51c6\u3002<br \/>\n2\u3001to space\u653e\u4e0d\u4e0b\u7684\uff0c\u76f4\u63a5\u653e\u5165\u8001\u751f\u4ee3\u3002<\/p>\n<p>\u5728\u56de\u6536\u540e\uff0c\u5982UseAdaptiveSizePolicy\uff0cPS GC\u4f1a\u6839\u636e\u8fd0\u884c\u72b6\u6001\u52a8\u6001\u8c03\u6574eden\u3001to\u4ee5\u53caTenuringThreshold\u7684\u5927\u5c0f\u3002\u5982\u679c\u4e0d\u5e0c\u671b\u52a8\u6001\u8c03\u6574\u53ef\u8bbe\u7f6e-XX:-UseAdaptiveSizePolicy\u3002\u5982\u5e0c\u671b\u8ddf\u8e2a\u6bcf\u6b21\u7684\u53d8\u5316\u60c5\u51b5\uff0c\u53ef\u5728\u542f\u52a2\u53c2\u6570\u4e0a\u589e\u52a0\uff1a PrintAdaptiveSizePolicy\u3002<\/p>\n<p>\u4e8c\u3001\u8001\u751f\u4ee3\u53ef\u7528GC<\/p>\n<p>1\u3001\u4e32\u884cGC(Serial Copying)\uff1aclient\u65b9\u5f0f\u4e0b\u9ed8\u8ba4GC\u65b9\u5f0f\uff0c\u53ef\u901a\u8fc7-XX:+UseSerialGC\u5f3a\u5236\u6307\u5b9a\u3002<\/p>\n<p>\u89e6\u53d1\u673a\u5236\u6c47\u603b\uff1a<br \/>\n1\uff09old gen\u7a7a\u95f4\u4e0d\u8db3\uff1b<br \/>\n2\uff09perm gen\u7a7a\u95f4\u4e0d\u8db3\uff1b<br \/>\n3\uff09minor gc\u65f6\u7684\u60b2\u89c2\u7b56\u7565\uff1b<br \/>\n4\uff09minor GC\u540e\u5728eden\u4e0a\u5206\u914d\u5185\u5b58\u4ecd\u7136\u5931\u8d25\uff1b<br \/>\n5\uff09\u6267\u884cheap dump\u65f6\uff1b<br \/>\n6\uff09\u5916\u90e8\u8c03\u7528System.gc\uff0c\u53ef\u901a\u8fc7-XX:+DisableExplicitGC\u6765\u7981\u6b62\u3002<\/p>\n<p>2\u3001\u5e76\u884c\u56de\u6536GC(Parallel Scavenge)\uff1a server\u6a21\u5f0f\u4e0b\u9ed8\u8ba4GC\u65b9\u5f0f\uff0c\u53ef\u901a\u8fc7-XX:+UseParallelGC\u5f3a\u5236\u6307\u5b9a\uff1b \u5e76\u884c\u7684\u7ebf\u7a0b\u6570\u4e3a\u5f53cpu core&lt;=8 ? cpu core : 3+(cpu core*5)\/8\u6216\u901a\u8fc7-XX:ParallelGCThreads=x\u6765\u5f3a\u5236\u6307\u5b9a\u3002\u5982ScavengeBeforeFullGC\u4e3atrue\uff08\u9ed8\u8ba4\u503c\uff09\uff0c\u5219\u5148\u6267\u884cminor GC\u3002<\/p>\n<p>3\u3001\u5e76\u884cCompacting\uff1a\u53ef\u901a\u8fc7-XX:+UseParallelOldGC\u5f3a\u5236\u6307\u5b9a\u3002<\/p>\n<p>4\u3001\u5e76\u53d1CMS\uff1a\u53ef\u901a\u8fc7-XX:+UseConcMarkSweepGC\u6765\u5f3a\u5236\u6307\u5b9a\u3002\u5e76\u53d1\u7684\u7ebf\u7a0b\u6570\u9ed8\u8ba4\u4e3a:( \u5e76\u884cGC\u7ebf\u7a0b\u6570+3)\/4\uff0c\u4e5f\u53ef\u901a\u8fc7ParallelCMSThreads\u6307\u5b9a\u3002<\/p>\n<p>\u89e6\u53d1\u673a\u5236\uff1a<br \/>\n1\u3001\u5f53\u8001\u751f\u4ee3\u7a7a\u95f4\u7684\u4f7f\u7528\u5230\u8fbe\u4e00\u5b9a\u6bd4\u7387\u65f6\u89e6\u53d1\uff1b<\/p>\n<p>Hotspot V 1.6\u4e2d\u9ed8\u8ba4\u4e3a65%\uff0c\u53ef\u901a\u8fc7PrintCMSInitiationStatistics\uff08\u6b64\u53c2\u6570\u5728V 1.5\u4e2d\u4e0d\u80fd\u7528\uff09\u6765\u67e5\u770b\u8fd9\u4e2a\u503c\u5230\u5e95\u662f\u591a\u5c11\uff1b\u53ef\u901a\u8fc7CMSInitiatingOccupancyFraction\u6765\u5f3a\u5236\u6307\u5b9a\uff0c\u9ed8\u8ba4\u503c\u5e76\u4e0d\u662f\u8d4b\u503c\u5728\u4e86\u8fd9\u4e2a\u503c\u4e0a\uff0c\u662f\u6839\u636e\u5982\u4e0b\u516c\u5f0f\u8ba1\u7b97\u51fa\u6765\u7684\uff1a ((100 &#8211; MinHeapFreeRatio) +(double)(CMSTriggerRatio * MinHeapFreeRatio) \/ 100.0)\/ 100.0; \u5176\u4e2d,MinHeapFreeRatio\u9ed8\u8ba4\u503c\uff1a 40\u00a0\u00a0 CMSTriggerRatio\u9ed8\u8ba4\u503c\uff1a 80\u3002<\/p>\n<p>2\u3001\u5f53perm gen\u91c7\u7528CMS\u6536\u96c6\u4e14\u7a7a\u95f4\u4f7f\u7528\u5230\u4e00\u5b9a\u6bd4\u7387\u65f6\u89e6\u53d1\uff1b<\/p>\n<p>perm gen\u91c7\u7528CMS\u6536\u96c6\u9700\u8bbe\u7f6e\uff1a-XX:+CMSClassUnloadingEnabled\u00a0\u00a0 Hotspot V 1.6\u4e2d\u9ed8\u8ba4\u4e3a65%\uff1b\u53ef\u901a\u8fc7CMSInitiatingPermOccupancyFraction\u6765\u5f3a\u5236\u6307\u5b9a\uff0c\u540c\u6837\uff0c\u5b83\u662f\u6839\u636e\u5982\u4e0b\u516c\u5f0f\u8ba1\u7b97\u51fa\u6765\u7684\uff1a((100 &#8211; MinHeapFreeRatio) +(double)(CMSTriggerPermRatio* MinHeapFreeRatio) \/ 100.0)\/ 100.0; \u5176\u4e2d\uff0cMinHeapFreeRatio\u9ed8\u8ba4\u503c\uff1a 40\u00a0\u00a0\u00a0 CMSTriggerPermRatio\u9ed8\u8ba4\u503c\uff1a 80\u3002<\/p>\n<p>3\u3001Hotspot\u6839\u636e\u6210\u672c\u8ba1\u7b97\u51b3\u5b9a\u662f\u5426\u9700\u8981\u6267\u884cCMS GC\uff1b\u53ef\u901a\u8fc7-XX:+UseCMSInitiatingOccupancyOnly\u6765\u53bb\u6389\u8fd9\u4e2a\u52a8\u6001\u6267\u884c\u7684\u7b56\u7565\u3002<br \/>\n4\u3001\u5916\u90e8\u8c03\u7528\u4e86System.gc\uff0c\u4e14\u8bbe\u7f6e\u4e86ExplicitGCInvokesConcurrent\uff1b\u9700\u8981\u6ce8\u610f\uff0c\u5728hotspot 6\u4e2d\uff0c\u5728\u8fd9\u79cd\u60c5\u51b5\u4e0b\u5982\u5e94\u7528\u540c\u65f6\u4f7f\u7528\u4e86NIO\uff0c\u53ef\u80fd\u4f1a\u51fa\u73b0bug\u3002<\/p>\n<p><strong>6\u3001GC\u7ec4\u5408<\/strong><\/p>\n<p>1\uff09\u9ed8\u8ba4GC\u7ec4\u5408<\/p>\n<p><a href=\"http:\/\/www.blogjava.net\/images\/blogjava_net\/chhbjh\/Windows-Live-Writer\/2d08114b62d1_AA6A\/image_9.png\"><img loading=\"lazy\" decoding=\"async\" title=\"image\" src=\"http:\/\/www.blogjava.net\/images\/blogjava_net\/chhbjh\/Windows-Live-Writer\/2d08114b62d1_AA6A\/image_thumb_3.png\" alt=\"image\" width=\"638\" height=\"125\" border=\"0\" \/><\/a><\/p>\n<p>2\uff09\u53ef\u9009\u7684GC\u7ec4\u5408<\/p>\n<p><a href=\"http:\/\/www.blogjava.net\/images\/blogjava_net\/chhbjh\/Windows-Live-Writer\/2d08114b62d1_AA6A\/image_11.png\"><img loading=\"lazy\" decoding=\"async\" title=\"image\" src=\"http:\/\/www.blogjava.net\/images\/blogjava_net\/chhbjh\/Windows-Live-Writer\/2d08114b62d1_AA6A\/image_thumb_4.png\" alt=\"image\" width=\"638\" height=\"441\" border=\"0\" \/><\/a><\/p>\n<p><strong>7\u3001GC\u76d1\u6d4b<\/strong><\/p>\n<p>1\uff09jstat \u2013gcutil [pid] [intervel] [count]<br \/>\n2\uff09-verbose:gc \/\/ \u53ef\u4ee5\u8f85\u52a9\u8f93\u51fa\u4e00\u4e9b\u8be6\u7ec6\u7684GC\u4fe1\u606f\uff1b-XX:+PrintGCDetails \/\/ \u8f93\u51faGC\u8be6\u7ec6\u4fe1\u606f\uff1b-XX:+PrintGCApplicationStoppedTime \/\/ \u8f93\u51faGC\u9020\u6210\u5e94\u7528\u6682\u505c\u7684\u65f6\u95f4<br \/>\n-XX:+PrintGCDateStamps \/\/ GC\u53d1\u751f\u7684\u65f6\u95f4\u4fe1\u606f\uff1b-XX:+PrintHeapAtGC \/\/ \u5728GC\u524d\u540e\u8f93\u51fa\u5806\u4e2d\u5404\u4e2a\u533a\u57df\u7684\u5927\u5c0f\uff1b-Xloggc:[file] \/\/ \u5c06GC\u4fe1\u606f\u8f93\u51fa\u5230\u5355\u72ec\u7684\u6587\u4ef6\u4e2d\uff0c\u5efa\u8bae\u90fd\u52a0\u4e0a\uff0c\u8fd9\u4e2a\u6d88\u8017\u4e0d\u5927\uff0c\u800c\u4e14\u5bf9\u67e5\u95ee\u9898\u548c\u8c03\u4f18\u6709\u5f88\u5927\u7684\u5e2e\u52a9\u3002gc\u7684\u65e5\u5fd7\u62ff\u4e0b\u6765\u540e\u53ef\u4f7f\u7528GCLogViewer\u6216gchisto\u8fdb\u884c\u5206\u6790\u3002<br \/>\n3\uff09\u56fe\u5f62\u5316\u7684\u60c5\u51b5\u4e0b\u53ef\u76f4\u63a5\u7528jvisualvm\u8fdb\u884c\u5206\u6790\u3002<\/p>\n<p>4\uff09\u67e5\u770b\u5185\u5b58\u7684\u6d88\u8017\u72b6\u51b5<\/p>\n<p>\uff081\uff09\u957f\u671f\u6d88\u8017\uff0c\u53ef\u4ee5\u76f4\u63a5dump\uff0c\u7136\u540eMAT(\u5185\u5b58\u5206\u6790\u5de5\u5177)\u67e5\u770b\u5373\u53ef<\/p>\n<p>\uff082\uff09\u77ed\u671f\u6d88\u8017\uff0c\u56fe\u5f62\u754c\u9762\u60c5\u51b5\u4e0b\uff0c\u53ef\u4f7f\u7528jvisualvm\u7684memory profiler\u6216jprofiler\u3002<\/p>\n<p><strong>8\u3001\u7cfb\u7edf\u8c03\u4f18\u65b9\u6cd5<\/strong><\/p>\n<p><strong>\u6b65\u9aa4\uff1a1\u3001\u8bc4\u4f30\u73b0\u72b6 2\u3001\u8bbe\u5b9a\u76ee\u6807 3\u3001\u5c1d\u8bd5\u8c03\u4f18 4\u3001\u8861\u91cf\u8c03\u4f18 5\u3001\u7ec6\u5fae\u8c03\u6574<\/strong><\/p>\n<p><strong>\u8bbe\u5b9a\u76ee\u6807\uff1a<\/strong><\/p>\n<p>1\uff09\u964d\u4f4eFull GC\u7684\u6267\u884c\u9891\u7387\uff1f<br \/>\n2\uff09\u964d\u4f4eFull GC\u7684\u6d88\u8017\u65f6\u95f4\uff1f<br \/>\n3\uff09\u964d\u4f4eFull GC\u6240\u9020\u6210\u7684\u5e94\u7528\u505c\u987f\u65f6\u95f4\uff1f<br \/>\n4\uff09\u964d\u4f4eMinor GC\u6267\u884c\u9891\u7387\uff1f<br \/>\n5\uff09\u964d\u4f4eMinor GC\u6d88\u8017\u65f6\u95f4\uff1f<br \/>\n\u4f8b\u5982\u67d0\u7cfb\u7edf\u7684GC\u8c03\u4f18\u76ee\u6807\uff1a\u964d\u4f4eFull GC\u6267\u884c\u9891\u7387\u7684\u540c\u65f6\uff0c\u5c3d\u53ef\u80fd\u964d\u4f4eminor GC\u7684\u6267\u884c\u9891\u7387\u3001\u6d88\u8017\u65f6\u95f4\u4ee5\u53caGC\u5bf9\u5e94\u7528\u9020\u6210\u7684\u505c\u987f\u65f6\u95f4\u3002<\/p>\n<p><strong>\u8861\u91cf\u8c03\u4f18\uff1a<\/strong><\/p>\n<p>1\u3001\u8861\u91cf\u5de5\u5177<br \/>\n1\uff09\u6253\u5370GC\u65e5\u5fd7\u4fe1\u606f\uff1a-XX:+PrintGCDetails \u2013XX:+PrintGCApplicationStoppedTime -Xloggc: {\u6587\u4ef6\u540d}\u00a0 -XX:+PrintGCTimeStamps<br \/>\n2\uff09jmap\uff1a\uff08\u7531\u4e8e\u6bcf\u4e2a\u7248\u672cjvm\u7684\u9ed8\u8ba4\u503c\u53ef\u80fd\u4f1a\u6709\u6539\u53d8\uff0c\u5efa\u8bae\u8fd8\u662f\u7528jmap\u9996\u5148\u89c2\u5bdf\u4e0b\u76ee\u524d\u6bcf\u4e2a\u4ee3\u7684\u5185\u5b58\u5927\u5c0f\u3001GC\u65b9\u5f0f\uff09 \uf04a<br \/>\n3\uff09\u8fd0\u884c\u72b6\u51b5\u76d1\u6d4b\u5de5\u5177\uff1ajstat\u3001jvisualvm\u3001sar \u3001gclogviewer<\/p>\n<p>2\u3001\u5e94\u6536\u96c6\u7684\u4fe1\u606f<br \/>\n1\uff09minor gc\u7684\u6267\u884c\u9891\u7387\uff1bfull gc\u7684\u6267\u884c\u9891\u7387\uff0c\u6bcf\u6b21GC\u8017\u65f6\u591a\u5c11\uff1f<br \/>\n2\uff09\u9ad8\u5cf0\u671f\u4ec0\u4e48\u72b6\u51b5\uff1f<br \/>\n3\uff09minor gc\u56de\u6536\u7684\u6548\u679c\u5982\u4f55\uff1fsurvivor\u7684\u6d88\u8017\u72b6\u51b5\u5982\u4f55\uff0c\u6bcf\u6b21\u6709\u591a\u5c11\u5bf9\u8c61\u4f1a\u8fdb\u5165\u8001\u751f\u4ee3\uff1f<br \/>\n4\uff09full gc\u56de\u6536\u7684\u6548\u679c\u5982\u4f55\uff1f\uff08\u7b80\u5355\u7684<strong>memory leak<\/strong>\u5224\u65ad\u65b9\u6cd5\uff09<br \/>\n5\uff09\u7cfb\u7edf\u7684load\u3001cpu\u6d88\u8017\u3001qps or tps\u3001\u54cd\u5e94\u65f6\u95f4<\/p>\n<p>QPS\u6bcf\u79d2\u67e5\u8be2\u7387\uff1a\u662f\u5bf9\u4e00\u4e2a\u7279\u5b9a\u7684\u67e5\u8be2\u670d\u52a1\u5668\u5728\u89c4\u5b9a\u65f6\u95f4\u5185\u6240\u5904\u7406\u6d41\u91cf\u591a\u5c11\u7684\u8861\u91cf\u6807\u51c6\u3002\u5728\u56e0\u7279\u7f51\u4e0a\uff0c\u4f5c\u4e3a\u57df\u540d\u670d\u52a1\u5668\u7684\u673a\u5668\u6027\u80fd\u7ecf\u5e38\u7528\u6bcf\u79d2\u67e5\u8be2\u7387\u6765\u8861\u91cf\u3002\u5bf9\u5e94fetches\/sec\uff0c\u5373\u6bcf\u79d2\u7684\u54cd\u5e94\u8bf7\u6c42\u6570\uff0c\u4e5f\u5373\u662f\u6700\u5927\u541e\u5410\u80fd\u529b\u3002<br \/>\nTPS(Transaction Per Second)\uff1a\u6bcf\u79d2\u949f\u7cfb\u7edf\u80fd\u591f\u5904\u7406\u7684\u4ea4\u6613\u6216\u4e8b\u52a1\u7684\u6570\u91cf\u3002<\/p>\n<p><strong>\u5c1d\u8bd5\u8c03\u4f18\uff1a<\/strong><\/p>\n<p>\u6ce8\u610fJava RMI\u7684\u5b9a\u65f6GC\u89e6\u53d1\u673a\u5236\uff0c\u53ef\u901a\u8fc7\uff1a-XX:+DisableExplicitGC\u6765\u7981\u6b62\u6216\u901a\u8fc7 -Dsun.rmi.dgc.server.gcInterval=3600000\u6765\u63a7\u5236\u89e6\u53d1\u7684\u65f6\u95f4\u3002<\/p>\n<p>1\uff09\u964d\u4f4eFull GC\u6267\u884c\u9891\u7387 \u2013 \u901a\u5e38\u74f6\u9888<br \/>\n\u8001\u751f\u4ee3\u672c\u8eab\u5360\u7528\u7684\u5185\u5b58\u7a7a\u95f4\u5c31\u4e00\u76f4\u504f\u9ad8\uff0c\u6240\u4ee5\u53ea\u8981\u7a0d\u5fae\u653e\u70b9\u5bf9\u8c61\u5230\u8001\u751f\u4ee3\uff0c\u5c31full GC\u4e86\uff1b<br \/>\n\u901a\u5e38\u539f\u56e0\uff1a\u7cfb\u7edf\u7f13\u5b58\u7684\u4e1c\u897f\u592a\u591a\uff1b<br \/>\n\u4f8b\u5982\uff1a\u4f7f\u7528oracle 10g\u9a71\u52a8\u65f6preparedstatement cache\u592a\u5927\uff1b<br \/>\n\u67e5\u627e\u529e\u6cd5\uff1a\u73b0\u6267\u884cDump\u7136\u540e\u518d\u8fdb\u884cMAT\u5206\u6790\uff1b<\/p>\n<p>\uff081\uff09Minor GC\u540e\u603b\u662f\u6709\u5bf9\u8c61\u4e0d\u65ad\u7684\u8fdb\u5165\u8001\u751f\u4ee3\uff0c\u5bfc\u81f4\u8001\u751f\u4ee3\u4e0d\u65ad\u7684\u6ee1<br \/>\n\u901a\u5e38\u539f\u56e0\uff1aSurvivor\u592a\u5c0f\u4e86<br \/>\n\u7cfb\u7edf\u8868\u73b0\uff1a\u7cfb\u7edf\u54cd\u5e94\u592a\u6162\u3001\u8bf7\u6c42\u91cf\u592a\u5927\u3001\u6bcf\u6b21\u8bf7\u6c42\u5206\u914d\u7684\u5185\u5b58\u592a\u591a\u3001\u5206\u914d\u7684\u5bf9\u8c61\u592a\u5927&#8230;<br \/>\n\u67e5\u627e\u529e\u6cd5\uff1a\u5206\u6790\u4e24\u6b21minor GC\u4e4b\u95f4\u5230\u5e95\u54ea\u4e9b\u5730\u65b9\u5206\u914d\u4e86\u5185\u5b58\uff1b<br \/>\n\u5229\u7528jstat\u89c2\u5bdfSurvivor\u7684\u6d88\u8017\u72b6\u51b5\uff0c-XX:PrintHeapAtGC\uff0c\u8f93\u51faGC\u524d\u540e\u7684\u8be6\u7ec6\u4fe1\u606f\uff1b<br \/>\n\u5bf9\u4e8e\u7cfb\u7edf\u54cd\u5e94\u6162\u53ef\u4ee5\u91c7\u7528\u7cfb\u7edf\u4f18\u5316\uff0c\u4e0d\u662fGC\u4f18\u5316\u7684\u5185\u5bb9\uff1b<\/p>\n<p>\uff082\uff09\u8001\u751f\u4ee3\u7684\u5185\u5b58\u5360\u7528\u4e00\u76f4\u504f\u9ad8<br \/>\n\u8c03\u4f18\u65b9\u6cd5\uff1a\u2460 \u6269\u5927\u8001\u751f\u4ee3\u7684\u5927\u5c0f\uff08\u51cf\u5c11\u65b0\u751f\u4ee3\u7684\u5927\u5c0f\u6216\u8c03\u5927heap\u7684 \u5927\u5c0f\uff09\uff1b<br \/>\n\u51cf\u5c11new\u6ce8\u610f\u5bf9minor gc\u7684\u5f71\u54cd\u5e76\u4e14\u540c\u65f6\u6709\u53ef\u80fd\u9020\u6210full gc\u8fd8\u662f\u4e25\u91cd\uff1b<br \/>\n\u8c03\u5927heap\u6ce8\u610ffull gc\u7684\u65f6\u95f4\u7684\u5ef6\u957f\uff0ccpu\u591f\u5f3a\u608d\u561b\uff0cos\u662f32 bit\u7684\u5417\uff1f<br \/>\n\u2461 \u7a0b\u5e8f\u4f18\u5316\uff08\u53bb\u6389\u4e00\u4e9b\u4e0d\u5fc5\u8981\u7684\u7f13\u5b58\uff09<\/p>\n<p>\uff083\uff09Minor GC\u540e\u603b\u662f\u6709\u5bf9\u8c61\u4e0d\u65ad\u7684\u8fdb\u5165\u8001\u751f\u4ee3<br \/>\n\u524d\u63d0\uff1a\u8fd9\u4e9b\u8fdb\u5165\u8001\u751f\u4ee3\u7684\u5bf9\u8c61\u5728full GC\u65f6\u5927\u90e8\u5206\u90fd\u4f1a\u88ab\u56de\u6536<br \/>\n\u8c03\u4f18\u65b9\u6cd5\uff1a<br \/>\n\u2460 \u964d\u4f4eMinor GC\u7684\u6267\u884c\u9891\u7387\uff1b<br \/>\n\u2461 \u8ba9\u5bf9\u8c61\u5c3d\u91cf\u5728Minor GC\u4e2d\u5c31\u88ab\u56de\u6536\u6389\uff1a\u589e\u5927Eden\u533a\u3001\u589e\u5927survivor\u3001\u589e\u5927TenuringThreshold\uff1b\u6ce8\u610f\u8fd9\u4e9b\u53ef\u80fd\u4f1a\u9020\u6210minor gc\u6267\u884c\u9891\u7e41\uff1b<br \/>\n\u2462 \u5207\u6362\u6210CMS GC\uff1a\u8001\u751f\u4ee3\u8fd8\u6ca1\u6709\u6ee1\u5c31\u56de\u6536\u6389\uff0c\u4ece\u800c\u964d\u4f4eFull GC\u89e6\u53d1\u7684\u53ef\u80fd\u6027\uff1b<br \/>\n\u2463 \u7a0b\u5e8f\u4f18\u5316\uff1a\u63d0\u5347\u54cd\u5e94\u901f\u5ea6\u3001\u964d\u4f4e\u6bcf\u6b21\u8bf7\u6c42\u5206\u914d\u7684\u5185\u5b58\u3001<\/p>\n<p>\uff084\uff09\u964d\u4f4e\u5355\u6b21Full GC\u7684\u6267\u884c\u65f6\u95f4<br \/>\n\u901a\u5e38\u539f\u56e0\uff1a\u8001\u751f\u4ee3\u592a\u5927\u4e86&#8230;<br \/>\n\u8c03\u4f18\u65b9\u6cd5\uff1a1\uff09\u662f\u5e76\u884cGC\u5417\uff1f\u00a0\u00a0 2\uff09\u5347\u7ea7CPU\u00a0 3\uff09\u51cf\u5c0fHeap\u6216\u8001\u751f\u4ee3<\/p>\n<p>\uff085\uff09\u964d\u4f4eMinor GC\u6267\u884c\u9891\u7387<br \/>\n\u901a\u5e38\u539f\u56e0\uff1a\u6bcf\u6b21\u8bf7\u6c42\u5206\u914d\u7684\u5185\u5b58\u591a\u3001\u8bf7\u6c42\u91cf\u5927<br \/>\n\u901a\u5e38\u529e\u6cd5\uff1a1\uff09\u6269\u5927heap\u3001\u6269\u5927\u65b0\u751f\u4ee3\u3001\u6269\u5927eden\u3002\u6ce8\u610f\u70b9\uff1a\u964d\u4f4e\u6bcf\u6b21\u8bf7\u6c42\u5206\u914d\u7684\u5185\u5b58\uff1b\u6a2a\u5411\u589e\u52a0\u673a\u5668\u7684\u6570\u91cf\u5206\u62c5\u8bf7\u6c42\u7684\u6570\u91cf\u3002<\/p>\n<p>\uff086\uff09\u964d\u4f4eMinor GC\u6267\u884c\u65f6\u95f4<br \/>\n\u901a\u5e38\u539f\u56e0\uff1a\u65b0\u751f\u4ee3\u592a\u5927\u4e86\uff0c\u54cd\u5e94\u901f\u5ea6\u592a\u6162\u4e86\uff0c\u5bfc\u81f4\u6bcf\u6b21Minor GC\u65f6\u5b58\u6d3b\u7684\u5bf9\u8c61\u591a<br \/>\n\u901a\u5e38\u529e\u6cd5\uff1a1\uff09\u51cf\u5c0f\u70b9\u65b0\u751f\u4ee3\u5427\uff1b2\uff09\u589e\u52a0CPU\u7684\u6570\u91cf\u3001\u5347\u7ea7CPU\u7684\u914d\u7f6e\uff1b\u52a0\u5feb\u7cfb\u7edf\u7684\u54cd\u5e94\u901f\u5ea6<\/p>\n<p><strong>\u7ec6\u5fae\u8c03\u6574\uff1a<\/strong><\/p>\n<p>\u9996\u5148\u9700\u8981\u4e86\u89e3\u4ee5\u4e0b\u60c5\u51b5\uff1a<\/p>\n<p>\u2460 \u5f53\u54cd\u5e94\u901f\u5ea6\u4e0b\u964d\u5230\u591a\u5c11\u6216\u8bf7\u6c42\u91cf\u4e0a\u6da8\u5230\u591a\u5c11\u65f6\uff0c\u7cfb\u7edf\u4f1a\u5b95\u6389\uff1f<\/p>\n<p>\u2461 \u53c2\u6570\u8c03\u6574\u540e\u7cfb\u7edf\u591a\u4e45\u4f1a\u6267\u884c\u4e00\u6b21Minor GC\uff0c\u591a\u4e45\u4f1a\u6267\u884c\u4e00\u6b21Full GC\uff0c\u9ad8\u5cf0\u671f\u4f1a\u5982\u4f55\uff1f<\/p>\n<p>\u9700\u8981\u8ba1\u7b97\u7684\u91cf\uff1a<\/p>\n<p>\u2460\u6bcf\u6b21\u8bf7\u6c42\u5e73\u5747\u9700\u8981\u5206\u914d\u591a\u5c11\u5185\u5b58\uff1f\u7cfb\u7edf\u7684\u5e73\u5747\u54cd\u5e94\u65f6\u95f4\u662f\u591a\u5c11\u5462\uff1f\u8bf7\u6c42\u91cf\u662f\u591a\u5c11\u3001\u591a\u5e38\u65f6\u95f4\u6267\u884c\u4e00\u6b21Minor GC\u3001Full GC\uff1f<\/p>\n<p>\u2461\u73b0\u6709\u53c2\u6570\u4e0b\uff0c\u5e94\u8be5\u662f\u591a\u4e45\u4e00\u6b21Minor GC\u3001Full GC\uff0c\u5bf9\u6bd4\u771f\u5b9e\u72b6\u51b5\uff0c\u505a\u4e00\u5b9a\u7684\u8c03\u6574\uff1b<\/p>\n<p>\u5fc5\u6740\u6280\uff1a\u63d0\u5347\u54cd\u5e94\u901f\u5ea6\u3001\u964d\u4f4e\u6bcf\u6b21\u8bf7\u6c42\u5206\u914d\u7684\u5185\u5b58\uff1f<\/p>\n<p><strong>9\u3001\u7cfb\u7edf\u8c03\u4f18\u4e3e\u4f8b<\/strong><\/p>\n<p>\u73b0\u8c61\uff1a1\u3001\u7cfb\u7edf\u54cd\u5e94\u901f\u5ea6\u5927\u6982\u4e3a100ms\uff1b2\u3001\u5f53\u7cfb\u7edfQPS\u589e\u957f\u523040\u65f6\uff0c\u673a\u5668\u6bcf\u96945\u79d2\u5c31\u6267\u884c\u4e00\u6b21minor gc\uff0c\u6bcf\u96943\u5206\u949f\u5c31\u6267\u884c\u4e00\u6b21full gc\uff0c\u5e76\u4e14\u5f88\u5feb\u5c31\u4e00\u76f4full GC\u4e86\uff1b4\u3001\u6bcf\u6b21Full gc\u540e\u65e7\u751f\u4ee3\u5927\u6982\u4f1a\u6d88\u8017400M\uff0c\u6709\u70b9\u591a\u4e86\u3002<\/p>\n<p>\u89e3\u51b3\u65b9\u6848\uff1a\u89e3\u51b3Full GC\u6b21\u6570\u8fc7\u591a\u7684\u95ee\u9898<\/p>\n<p>\uff081\uff09\u964d\u4f4e\u54cd\u5e94\u65f6\u95f4\u6216\u8bf7\u6c42\u6b21\u6570\uff0c\u8fd9\u4e2a\u9700\u8981\u91cd\u6784\uff0c\u6bd4\u8f83\u9ebb\u70e6\uff1b\u2014\u2014\u8fd9\u4e2a\u662f\u7ec8\u6781\u65b9\u6cd5\uff0c\u5f80\u5f80\u80fd\u591f\u987a\u5229\u7684\u89e3\u51b3\u95ee\u9898\uff0c\u56e0\u4e3a\u5927\u90e8\u5206\u7684\u95ee\u9898\u5747\u662f\u7531\u7a0b\u5e8f\u81ea\u8eab\u9020\u6210\u7684\u3002<\/p>\n<p>\uff082\uff09\u51cf\u5c11\u8001\u751f\u4ee3\u5185\u5b58\u7684\u6d88\u8017\uff0c\u6bd4\u8f83\u9760\u8c31\uff1b\u2014\u2014\u53ef\u4ee5\u901a\u8fc7\u5206\u6790Dump\u6587\u4ef6\uff08jmap dump\uff09\uff0c\u5e76\u5229\u7528MAT\u67e5\u627e\u5185\u5b58\u6d88\u8017\u7684\u539f\u56e0\uff0c\u4ece\u800c\u53d1\u73b0\u7a0b\u5e8f\u4e2d\u9020\u6210\u8001\u751f\u4ee3\u5185\u5b58\u6d88\u8017\u7684\u539f\u56e0\u3002<\/p>\n<p>\uff083\uff09\u51cf\u5c11\u6bcf\u6b21\u8bf7\u6c42\u7684\u5185\u5b58\u7684\u6d88\u8017\uff0c\u8c8c\u4f3c\u6bd4\u8f83\u9760\u8c31\uff1b\u2014\u2014\u8fd9\u4e2a\u662f\u6d77\u5e02\u8703\u697c\uff0c\u6ca1\u6709\u592a\u597d\u7684\u529e\u6cd5\u3002<\/p>\n<p>\uff084\uff09\u964d\u4f4eGC\u9020\u6210\u7684\u5e94\u7528\u6682\u505c\u7684\u65f6\u95f4\u2014\u2014\u53ef\u4ee5\u91c7\u7528CMS GS\u5783\u573e\u56de\u6536\u5668\u3002\u53c2\u6570\u8bbe\u7f6e\u5982\u4e0b\uff1a<\/p>\n<p>-Xms1536m -Xmx1536m -Xmn700m -XX:SurvivorRatio=7 -XX:+UseConcMarkSweepGC -XX:+UseCMSCompactAtFullCollection<\/p>\n<p>-XX:CMSMaxAbortablePrecleanTime=1000 -XX:+CMSClassUnloadingEnabled -XX:+UseCMSInitiatingOccupancyOnly -XX:+DisableExplicitGC<\/p>\n<p>\uff085\uff09\u51cf\u5c11\u6bcf\u6b21minor gc\u664b\u5347\u5230old\u7684\u5bf9\u8c61\u3002\u53ef\u9009\u65b9\u6cd5\uff1a1\uff09 \u8c03\u5927\u65b0\u751f\u4ee3\u30022\uff09\u8c03\u5927Survivor\u30023\uff09\u8c03\u5927TenuringThreshold\u3002<\/p>\n<p>\u8c03\u5927Survivor\uff1a\u5f53\u524d\u91c7\u7528PS GC\uff0cSurvivor space\u4f1a\u88ab\u52a8\u6001\u8c03\u6574\u3002\u7531\u4e8e\u8c03\u6574\u5e45\u5ea6\u5f88\u5c0f\uff0c\u5bfc\u81f4\u4e86\u7ecf\u5e38\u6709\u5bf9\u8c61\u76f4\u63a5\u8f6c\u79fb\u5230\u4e86\u8001\u751f\u4ee3\uff1b\u4e8e\u662f\u7981\u6b62Survivor\u533a\u7684\u52a8\u6001\u8c03\u6574\u4e86\uff0c-XX:-UseAdaptiveSizePolicy\uff0c\u5e76\u8ba1\u7b97Survivor Space\u9700\u8981\u7684\u5927\u5c0f\uff0c\u4e8e\u662f\u7ee7\u7eed\u89c2\u5bdf\uff0c\u5e76\u505a\u5fae\u8c03\u2026\u3002\u6700\u7ec8\u5c06Full GC\u63a8\u8fdf\u52302\u5c0f\u65f61\u6b21\u3002<\/p>\n<p><strong>10\u3001\u5783\u573e\u56de\u6536\u7684\u5b9e\u73b0\u539f\u7406<\/strong><\/p>\n<p>\u5185\u5b58\u56de\u6536\u7684\u5b9e\u73b0\u65b9\u6cd5\uff1a1\uff09\u5f15\u7528\u8ba1\u6570\uff1a\u4e0d\u9002\u5408\u590d\u6742\u5bf9\u8c61\u7684\u5f15\u7528\u5173\u7cfb\uff0c\u5c24\u5176\u662f\u5faa\u73af\u4f9d\u8d56\u7684\u573a\u666f\u30022\uff09\u6709\u5411\u56feTracing\uff1a\u9002\u5408\u4e8e\u590d\u6742\u5bf9\u8c61\u7684\u5f15\u7528\u5173\u7cfb\u573a\u666f\uff0cHotspot\u91c7\u7528\u8fd9\u79cd\u3002\u5e38\u7528\u7b97\u6cd5\uff1aCopying\u3001Mark-Sweep\u3001Mark-Compact\u3002<\/p>\n<p>Hotspot\u4eceroot set\u5f00\u59cb\u626b\u63cf\u6709\u5f15\u7528\u7684\u5bf9\u8c61\u5e76\u5bf9Reference\u7c7b\u578b\u7684\u5bf9\u8c61\u8fdb\u884c\u7279\u6b8a\u5904\u7406\u3002<br \/>\n\u4ee5\u4e0b\u662fRoot Set\u7684\u5217\u8868\uff1a1\uff09\u5f53\u524d\u6b63\u5728\u6267\u884c\u7684\u7ebf\u7a0b\uff1b2\uff09\u5168\u5c40\/\u9759\u6001\u53d8\u91cf\uff1b3\uff09JVM Handles\uff1b4\uff09JNI \u3010 Java Native Interface \u3011Handles\uff1b<\/p>\n<p>\u53e6\u5916\uff1aminor GC\u53ea\u626b\u63cf\u65b0\u751f\u4ee3\uff0c\u5f53\u8001\u751f\u4ee3\u7684\u5bf9\u8c61\u5f15\u7528\u4e86\u65b0\u751f\u4ee3\u7684\u5bf9\u8c61\u65f6\uff0c\u4f1a\u91c7\u7528\u5982\u4e0b\u7684\u5904\u7406\u65b9\u5f0f\uff1a\u5728\u7ed9\u5bf9\u8c61\u8d4b\u5f15\u7528\u65f6\uff0c\u4f1a\u7ecf\u8fc7\u4e00\u4e2awrite barrier\u7684\u8fc7\u7a0b\uff0c\u4ee5\u4fbf\u68c0\u67e5\u662f\u5426\u6709\u8001\u751f\u4ee3\u5f15\u7528\u65b0\u751f\u4ee3\u5bf9\u8c61\u7684\u60c5\u51b5\uff0c\u5982\u6709\u5219\u8bb0\u5f55\u5230remember set\u4e2d\u3002\u5e76\u5728minor gc\u65f6\uff0cremember set\u6307\u5411\u7684\u65b0\u751f\u4ee3\u5bf9\u8c61\u4e5f\u4f5c\u4e3aroot set\u3002<\/p>\n<p><strong>\u65b0\u751f\u4ee3\u4e32\u884cGC(Serial Copying)\uff1a<\/strong><\/p>\n<p>\u65b0\u751f\u4ee3\u4e32\u884cGC(Serial Copying)\u5b8c\u6574\u5185\u5b58\u7684\u5206\u914d\u7b56\u7565\uff1a<\/p>\n<p>1\uff09\u9996\u5148\u5728TLAB\uff08\u672c\u5730\u7ebf\u7a0b\u5206\u914d\u7f13\u51b2\u533a\uff09\u4e0a\u5c1d\u8bd5\u5206\u914d\uff1b<br \/>\n2\uff09\u68c0\u67e5\u662f\u5426\u9700\u8981\u5728\u65b0\u751f\u4ee3\u4e0a\u5206\u914d\uff0c\u5982\u9700\u8981\u5206\u914d\u7684\u5927\u5c0f\u5c0f\u4e8ePretenureSizeThreshold\uff0c\u5219\u5728eden\u533a\u4e0a\u8fdb\u884c\u5206\u914d\uff0c\u5206\u914d\u6210\u529f\u5219\u8fd4\u56de\uff1b\u5206\u914d\u5931\u8d25\u5219\u7ee7\u7eed\uff1b<br \/>\n3\uff09\u68c0\u67e5\u662f\u5426\u9700\u8981\u5c1d\u8bd5\u5728\u8001\u751f\u4ee3\u4e0a\u5206\u914d\uff0c\u5982\u9700\u8981\uff0c\u5219\u904d\u5386\u6240\u6709\u4ee3\u5e76\u68c0\u67e5\u662f\u5426\u53ef\u5728\u8be5\u4ee3\u4e0a\u5206\u914d\uff0c\u5982\u53ef\u4ee5\u5219\u8fdb\u884c\u5206\u914d\uff1b\u5982\u4e0d\u9700\u8981\u5728\u8001\u751f\u4ee3\u4e0a\u5c1d\u8bd5\u5206\u914d\uff0c\u5219\u7ee7\u7eed\uff1b<br \/>\n4\uff09\u6839\u636e\u7b56\u7565\u51b3\u5b9a\u6267\u884c\u65b0\u751f\u4ee3GC\u6216Full GC\uff0c\u6267\u884cfull gc\u65f6\u4e0d\u6e05\u9664soft Ref\uff1b<br \/>\n5\uff09\u5982\u9700\u8981\u5206\u914d\u7684\u5927\u5c0f\u5927\u4e8ePretenureSizeThreshold\uff0c\u5c1d\u8bd5\u5728\u8001\u751f\u4ee3\u4e0a\u5206\u914d\uff0c\u5426\u5219\u5c1d\u8bd5\u5728\u65b0\u751f\u4ee3\u4e0a\u5206\u914d\uff1b<br \/>\n6\uff09\u5c1d\u8bd5\u6269\u5927\u5806\u5e76\u5206\u914d\uff1b<br \/>\n7\uff09\u6267\u884cfull gc\uff0c\u5e76\u6e05\u9664\u6240\u6709soft Ref\uff0c\u6309\u6b65\u9aa45\u7ee7\u7eed\u5c1d\u8bd5\u5206\u914d\u3002<\/p>\n<p>\u65b0\u751f\u4ee3\u4e32\u884cGC(Serial Copying)\u5b8c\u6574\u5185\u5b58\u56de\u6536\u7b56\u7565<br \/>\n1\uff09\u68c0\u67e5to\u662f\u5426\u4e3a\u7a7a\uff0c\u4e0d\u4e3a\u7a7a\u8fd4\u56defalse\uff1b<br \/>\n2\uff09\u68c0\u67e5\u8001\u751f\u4ee3\u5269\u4f59\u7a7a\u95f4\u662f\u5426\u5927\u4e8e\u5f53\u524deden+from\u5df2\u7528\u7684\u5927\u5c0f\uff0c\u5982\u5927\u4e8e\u5219\u8fd4\u56detrue\uff0c\u5982\u5c0f\u4e8e\u4e14HandlePromotionFailure\u4e3atrue\uff0c\u5219\u68c0\u67e5\u5269\u4f59\u7a7a\u95f4\u662f\u5426\u5927\u4e8e\u4e4b\u524d\u6bcf\u6b21minor gc\u664b\u7ea7\u5230\u8001\u751f\u4ee3\u7684\u5e73\u5747\u5927\u5c0f\uff0c\u5982\u5927\u4e8e\u8fd4\u56detrue\uff0c\u5982\u5c0f\u4e8e\u8fd4\u56defalse\u3002<br \/>\n3\uff09\u5982\u4e0a\u9762\u7684\u7ed3\u679c\u4e3afalse\uff0c\u5219\u6267\u884cfull gc\uff1b\u5982\u4e0a\u9762\u7684\u7ed3\u679c\u4e3atrue\uff0c\u6267\u884c\u4e0b\u9762\u7684\u6b65\u9aa4\uff1b<br \/>\n4\uff09\u626b\u63cf\u5f15\u7528\u5173\u7cfb\uff0c\u5c06\u6d3b\u7684\u5bf9\u8c61copy\u5230to space\uff0c\u5982\u5bf9\u8c61\u5728minor gc\u4e2d\u7684\u5b58\u6d3b\u6b21\u6570\u8d85\u8fc7tenuring_threshold\u6216\u5206\u914d\u5931\u8d25\uff0c\u5219\u5f80\u8001\u751f\u4ee3\u590d\u5236\uff0c\u5982\u4ecd\u7136\u590d\u5236\u5931\u8d25\uff0c\u5219\u53d6\u51b3\u4e8eHandlePromotionFailure\uff0c\u5982\u4e0d\u9700\u8981\u5904\u7406\uff0c\u76f4\u63a5\u629b\u51faOOM\uff0c\u5e76\u9000\u51favm\uff0c\u5982\u9700\u5904\u7406\uff0c\u5219\u4fdd\u6301\u8fd9\u4e9b\u65b0\u751f\u4ee3\u5bf9\u8c61\u4e0d\u52a8\uff1b<\/p>\n<p><strong>\u65b0\u751f\u4ee3\u53ef\u7528GC-PS<\/strong><\/p>\n<p>\u5b8c\u6574\u5185\u5b58\u5206\u914d\u7b56\u7565<br \/>\n1\uff09\u5148\u5728TLAB\u4e0a\u5206\u914d\uff0c\u5206\u914d\u5931\u8d25\u5219\u76f4\u63a5\u5728eden\u4e0a\u5206\u914d\uff1b<br \/>\n2\uff09\u5f53eden\u4e0a\u5206\u914d\u5931\u8d25\u65f6\uff0c\u68c0\u67e5\u9700\u8981\u5206\u914d\u7684\u5927\u5c0f\u662f\u5426 &gt;= eden space\u7684\u4e00\u534a\uff0c\u5982\u662f\uff0c\u5219\u76f4\u63a5\u5728\u8001\u751f\u4ee3\u5206\u914d\uff1b<br \/>\n3\uff09\u5982\u5206\u914d\u4ecd\u7136\u5931\u8d25\uff0c\u4e14gc\u5df2\u8d85\u8fc7\u9891\u7387\uff0c\u5219\u629b\u51faOOM\uff1b<br \/>\n4\uff09\u8fdb\u5165\u57fa\u672c\u5206\u914d\u7b56\u7565\u5931\u8d25\u7684\u6a21\u5f0f\uff1b<br \/>\n5\uff09\u6267\u884cPS GC\uff0c\u5728eden\u4e0a\u5206\u914d\uff1b<br \/>\n6\uff09\u6267\u884c\u975e\u6700\u5927\u538b\u7f29\u7684full gc\uff0c\u5728eden\u4e0a\u5206\u914d\uff1b<br \/>\n7\uff09\u5728\u65e7\u751f\u4ee3\u4e0a\u5206\u914d\uff1b<br \/>\n8\uff09\u6267\u884c\u6700\u5927\u538b\u7f29full gc\uff0c\u5728eden\u4e0a\u5206\u914d\uff1b<br \/>\n9\uff09\u5728\u65e7\u751f\u4ee3\u4e0a\u5206\u914d\uff1b<br \/>\n10\uff09\u5982\u8fd8\u5931\u8d25\uff0c\u56de\u52302\u3002<\/p>\n<p>\u6700\u60b2\u60e8\u7684\u60c5\u51b5\uff0c\u5206\u914d\u89e6\u53d1\u591a\u6b21PS GC\u548c\u591a\u6b21Full GC\uff0c\u76f4\u5230OOM\u3002<\/p>\n<p>\u5b8c\u6574\u5185\u5b58\u56de\u6536\u7b56\u7565<br \/>\n1\uff09\u5982gc\u6240\u6267\u884c\u7684\u65f6\u95f4\u8d85\u8fc7\uff0c\u76f4\u63a5\u7ed3\u675f\uff1b<br \/>\n2\uff09\u5148\u8c03\u7528invoke_nopolicy<br \/>\n2.1 \u5148\u68c0\u67e5\u662f\u4e0d\u662f\u8981\u5c1d\u8bd5scavenge\uff1b<br \/>\n2.1.1 to space\u5fc5\u987b\u4e3a\u7a7a\uff0c\u5982\u4e0d\u4e3a\u7a7a\uff0c\u5219\u8fd4\u56defalse\uff1b<br \/>\n2.1.2 \u83b7\u53d6\u4e4b\u524d\u6240\u6709minor gc\u664b\u7ea7\u5230old\u7684\u5e73\u5747\u5927\u5c0f\uff0c\u5e76\u5bf9\u6bd4\u76ee\u524deden+from\u5df2\u4f7f\u7528\u7684\u5927\u5c0f\uff0c\u53d6\u66f4\u5c0f\u7684\u4e00\u4e2a\u503c\uff0c\u5982\u8001\u751f\u4ee3\u5269\u4f59\u7a7a\u95f4\u5c0f\u4e8e\u6b64\u503c\uff0c\u5219\u8fd4\u56defalse\uff0c\u5982\u5927\u4e8e\u5219\u8fd4\u56detrue\uff1b<br \/>\n2.2 \u5982\u4e0d\u9700\u8981\u5c1d\u8bd5scavenge\uff0c\u5219\u8fd4\u56defalse\uff0c\u5426\u5219\u7ee7\u7eed\uff1b<br \/>\n2.3 \u591a\u7ebf\u7a0b\u626b\u63cf\u6d3b\u7684\u5bf9\u8c61\uff0c\u5e76\u57fa\u4e8dcopying\u7b97\u6cd5\u56de\u6536\uff0c\u56de\u6536\u65f6\u76f8\u5e94\u7684\u664b\u5347\u5bf9\u8c61\u5230\u65e7\u751f\u4ee3\uff1b<br \/>\n2.4 \u5982UseAdaptiveSizePolicy\uff0c\u90a3\u4e48\u91cd\u65b0\u8ba1\u7b97to space\u548ctenuringThreshold\u7684\u503c\uff0c\u5e76\u8c03\u6574\u3002<br \/>\n3\uff09\u5982invoke_nopolicy\u8fd4\u56de\u7684\u662ffalse\uff0c\u6216\u4e4b\u524d\u6240\u6709minor gc\u664b\u7ea7\u5230\u8001\u751f\u4ee3\u7684\u5e73\u5747\u5927\u5c0f &gt; \u65e7\u751f\u4ee3\u7684\u5269\u4f59\u7a7a\u95f4\uff0c\u90a3\u4e48\u7ee7\u7eed\u4e0b\u9762\u7684\u6b65\u9aa4\uff0c\u5426\u5219\u7ed3\u675f\uff1b<br \/>\n4\uff09\u5982UseParallelOldGC\uff0c\u5219\u6267\u884cPSParallelCompact\uff0c\u5982\u4e0d\u662fUseParallelOldGC\uff0c\u5219\u6267\u884cPSMarkSweep\u3002<\/p>\n<p><strong>\u8001\u751f\u4ee3\u5e76\u884cCMS GC\uff1a<\/strong><\/p>\n<p><strong>\u00a0\u00a0\u00a0 \u4f18\u7f3a\u70b9\uff1a<\/strong><\/p>\n<p><strong>\u00a0\u00a0\u00a0\u00a0<\/strong>1\uff09 \u5927\u90e8\u5206\u65f6\u5019\u548c\u5e94\u7528\u5e76\u53d1\u8fdb\u884c\uff0c\u56e0\u6b64\u53ea\u4f1a\u9020\u6210\u5f88\u77ed\u7684\u6682\u505c\u65f6\u95f4\uff1b<br \/>\n2\uff09\u6d6e\u52a8\u5783\u573e\uff0c\u6ca1\u529e\u6cd5\uff0c\u6240\u4ee5\u5185\u5b58\u7a7a\u95f4\u8981\u7a0d\u5fae\u5927\u4e00\u70b9\uff1b<br \/>\n3\uff09\u5185\u5b58\u788e\u7247\uff0c-XX:+UseCMSCompactAtFullCollection \u6765\u89e3\u51b3\uff1b<br \/>\n4\uff09 \u4e89\u62a2CPU\uff0c\u8fd9GC\u65b9\u5f0f\u5c31\u8fd9\u6837\uff1b<br \/>\n5\uff09\u591a\u6b21remark\uff0c\u6240\u4ee5\u603b\u7684gc\u65f6\u95f4\u4f1a\u6bd4\u5e76\u884c\u7684\u957f\uff1b<br \/>\n6\uff09\u5185\u5b58\u5206\u914d\uff0cfree list\u65b9\u5f0f\uff0cso\u6027\u80fd\u7a0d\u5dee\uff0c\u5bf9minor GC\u4f1a\u6709\u4e00\u70b9\u5f71\u54cd\uff1b<br \/>\n7\uff09\u548c\u5e94\u7528\u5e76\u53d1\uff0c\u6709\u53ef\u80fd\u5206\u914d\u548c\u56de\u6536\u540c\u65f6\uff0c\u4ea7\u751f\u7ade\u4e89\uff0c\u5f15\u5165\u4e86\u9501\uff0cJVM\u5206\u914d\u4f18\u5148\u3002<\/p>\n<p><strong>11\u3001TLAB\u7684\u89e3\u91ca<\/strong><\/p>\n<p>\u5806\u5185\u7684\u5bf9\u8c61\u6570\u636e\u662f\u5404\u4e2a\u7ebf\u7a0b\u6240\u5171\u4eab\u7684\uff0c\u6240\u4ee5\u5f53\u5728\u5806\u5185\u521b\u5efa\u65b0\u7684\u5bf9\u8c61\u65f6\uff0c\u5c31\u9700\u8981\u8fdb\u884c\u9501\u64cd\u4f5c\u3002\u9501\u64cd\u4f5c\u662f\u6bd4\u8f83\u8017\u65f6\uff0c\u56e0\u6b64JVM\u4e3a\u6bcf\u4e2a\u7ebf\u5728\u5806\u4e0a\u5206\u914d\u4e86\u4e00\u5757\u201c\u81ea\u7559\u5730\u201d\u2014\u2014TLAB(\u5168\u79f0\u662fThread Local Allocation Buffer)\uff0c\u4f4d\u4e8e\u5806\u5185\u5b58\u7684\u65b0\u751f\u4ee3\uff0c\u4e5f\u5c31\u662fEden\u533a\u3002\u6bcf\u4e2a\u7ebf\u7a0b\u5728\u521b\u5efa\u65b0\u7684\u5bf9\u8c61\u65f6\uff0c\u4f1a\u9996\u5148\u5c1d\u8bd5\u5728\u81ea\u5df1\u7684TLAB\u91cc\u8fdb\u884c\u5206\u914d\uff0c\u5982\u679c\u6210\u529f\u5c31\u8fd4\u56de\uff0c\u5931\u8d25\u4e86\u518d\u5230\u5171\u4eab\u7684Eden\u533a\u91cc\u53bb\u7533\u8bf7\u7a7a\u95f4\u3002\u5728\u7ebf\u7a0b\u81ea\u5df1\u7684TLAB\u533a\u57df\u521b\u5efa\u5bf9\u8c61\u5931\u8d25\u4e00\u822c\u6709\u4e24\u4e2a\u539f\u56e0\uff1a\u4e00\u662f\u5bf9\u8c61\u592a\u5927\uff0c\u4e8c\u662f\u81ea\u5df1\u7684TLAB\u533a\u5269\u4f59\u7a7a\u95f4\u4e0d\u591f\u3002\u901a\u5e38\u9ed8\u8ba4\u7684TLAB\u533a\u57df\u5927\u5c0f\u662fEden\u533a\u57df\u76841%\uff0c\u5f53\u7136\u4e5f\u53ef\u4ee5\u624b\u5de5\u8fdb\u884c\u8c03\u6574\uff0c\u5bf9\u5e94\u7684JVM\u53c2\u6570\u662f-XX:TLABWasteTargetPercent\u3002<\/p>\n<p>\u53c2\u8003\u6587\u732e\uff1a<\/p>\n<p>1\u3001Sun JDK 1.6 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