{"id":1707,"date":"2024-05-08T18:06:23","date_gmt":"2024-05-08T10:06:23","guid":{"rendered":"http:\/\/oneai.eu.org\/?p=1707"},"modified":"2024-05-08T18:06:23","modified_gmt":"2024-05-08T10:06:23","slug":"jvm%e7%b3%bb%e5%88%97%e4%b8%89jvm%e5%8f%82%e6%95%b0%e8%ae%be%e7%bd%ae%e3%80%81%e5%88%86%e6%9e%90","status":"publish","type":"post","link":"https:\/\/oneai.eu.org\/?p=1707","title":{"rendered":"JVM\u7cfb\u5217\u4e09:JVM\u53c2\u6570\u8bbe\u7f6e\u3001\u5206\u6790"},"content":{"rendered":"
\n       \u4e0d\u7ba1\u662fYGC\u8fd8\u662fFull GC,GC\u8fc7\u7a0b\u4e2d\u90fd\u4f1a\u5bf9\u5bfc\u81f4\u7a0b\u5e8f\u8fd0\u884c\u4e2d\u4e2d\u65ad,\u6b63\u786e\u7684\u9009\u62e9\u4e0d\u540c\u7684GC\u7b56\u7565<\/a>,\u8c03\u6574JVM\u3001GC\u7684\u53c2\u6570\uff0c\u53ef\u4ee5\u6781\u5927\u7684\u51cf\u5c11\u7531\u4e8eGC\u5de5\u4f5c\uff0c\u800c\u5bfc\u81f4\u7684\u7a0b\u5e8f\u8fd0\u884c\u4e2d\u65ad\u65b9\u9762\u7684\u95ee\u9898\uff0c\u8fdb\u800c\u9002\u5f53\u7684\u63d0\u9ad8Java\u7a0b\u5e8f\u7684\u5de5\u4f5c\u6548\u7387\u3002\u4f46\u662f\u8c03\u6574GC\u662f\u4ee5\u4e2a\u6781\u4e3a\u590d\u6742\u7684\u8fc7\u7a0b\uff0c\u7531\u4e8e\u5404\u4e2a\u7a0b\u5e8f\u5177\u5907\u4e0d\u540c\u7684\u7279\u70b9\uff0c\u5982\uff1aweb\u548cGUI\u7a0b\u5e8f\u5c31\u6709\u5f88\u5927\u533a\u522b\uff08Web\u53ef\u4ee5\u9002\u5f53\u7684\u505c\u987f\uff0c\u4f46GUI\u505c\u987f\u662f\u5ba2\u6237\u65e0\u6cd5\u63a5\u53d7\u7684\uff09\uff0c\u800c\u4e14\u7531\u4e8e\u8dd1\u5728\u5404\u4e2a\u673a\u5668\u4e0a\u7684\u914d\u7f6e\u4e0d\u540c\uff08\u4e3b\u8981cup\u4e2a\u6570\uff0c\u5185\u5b58\u4e0d\u540c\uff09\uff0c\u6240\u4ee5\u4f7f\u7528\u7684GC\u79cd\u7c7b\u4e5f\u4f1a\u4e0d\u540c(\u5982\u4f55\u9009\u62e9\u89c1GC\u79cd\u7c7b\u53ca\u5982\u4f55\u9009\u62e9<\/a>)\u3002\u672c\u6587\u5c06\u6ce8\u91cd\u4ecb\u7ecdJVM\u3001GC\u7684\u4e00\u4e9b\u91cd\u8981\u53c2\u6570\u7684\u8bbe\u7f6e\u6765\u63d0\u9ad8\u7cfb\u7edf\u7684\u6027\u80fd\u3002 <\/p>\n

       JVM\u5185\u5b58\u7ec4\u6210\u53caGC\u76f8\u5173\u5185\u5bb9\u8bf7\u89c1\u4e4b\u524d\u7684\u6587\u7ae0:JVM\u5185\u5b58\u7ec4\u6210<\/a> GC\u7b56\u7565&\u5185\u5b58\u7533\u8bf7<\/a>\u3002 <\/p>\n

JVM\u53c2\u6570\u7684\u542b\u4e49 <\/strong>\u5b9e\u4f8b\u89c1\u5b9e\u4f8b\u5206\u6790<\/a> <\/p>\n

\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
\u53c2\u6570\u540d\u79f0<\/strong><\/td>\n\u542b\u4e49<\/strong><\/td>\n\u9ed8\u8ba4\u503c<\/strong><\/td>\n <\/td>\n<\/tr>\n
-Xms<\/td>\n\u521d\u59cb\u5806\u5927\u5c0f<\/td>\n\u7269\u7406\u5185\u5b58\u76841\/64(<1GB)<\/td>\n\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.<\/td>\n<\/tr>\n
-Xmx<\/td>\n\u6700\u5927\u5806\u5927\u5c0f<\/td>\n\u7269\u7406\u5185\u5b58\u76841\/4(<1GB)<\/td>\n\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<\/td>\n<\/tr>\n
-Xmn<\/td>\n\u5e74\u8f7b\u4ee3\u5927\u5c0f(1.4or lator)<\/td>\n <\/td>\n\u6ce8\u610f<\/strong>\uff1a\u6b64\u5904\u7684\u5927\u5c0f\u662f\uff08eden+ 2 survivor space).\u4e0ejmap -heap\u4e2d\u663e\u793a\u7684New gen\u662f\u4e0d\u540c\u7684\u3002
\u6574\u4e2a\u5806\u5927\u5c0f=\u5e74\u8f7b\u4ee3\u5927\u5c0f + \u5e74\u8001\u4ee3\u5927\u5c0f + \u6301\u4e45\u4ee3\u5927\u5c0f.
\u589e\u5927\u5e74\u8f7b\u4ee3\u540e,\u5c06\u4f1a\u51cf\u5c0f\u5e74\u8001\u4ee3\u5927\u5c0f.\u6b64\u503c\u5bf9\u7cfb\u7edf\u6027\u80fd\u5f71\u54cd\u8f83\u5927,Sun\u5b98\u65b9\u63a8\u8350\u914d\u7f6e\u4e3a\u6574\u4e2a\u5806\u76843\/8<\/td>\n<\/tr>\n
-XX:NewSize<\/td>\n\u8bbe\u7f6e\u5e74\u8f7b\u4ee3\u5927\u5c0f(for 1.3\/1.4)<\/td>\n <\/td>\n <\/td>\n<\/tr>\n
-XX:MaxNewSize<\/td>\n\u5e74\u8f7b\u4ee3\u6700\u5927\u503c(for 1.3\/1.4)<\/td>\n <\/td>\n <\/td>\n<\/tr>\n
-XX:PermSize<\/td>\n\u8bbe\u7f6e\u6301\u4e45\u4ee3(perm gen)\u521d\u59cb\u503c<\/td>\n\u7269\u7406\u5185\u5b58\u76841\/64<\/td>\n <\/td>\n<\/tr>\n
-XX:MaxPermSize<\/td>\n\u8bbe\u7f6e\u6301\u4e45\u4ee3\u6700\u5927\u503c<\/td>\n\u7269\u7406\u5185\u5b58\u76841\/4<\/td>\n <\/td>\n<\/tr>\n
-Xss<\/td>\n\u6bcf\u4e2a\u7ebf\u7a0b\u7684\u5806\u6808\u5927\u5c0f<\/td>\n <\/td>\nJDK5.0\u4ee5\u540e\u6bcf\u4e2a\u7ebf\u7a0b\u5806\u6808\u5927\u5c0f\u4e3a1M,\u4ee5\u524d\u6bcf\u4e2a\u7ebf\u7a0b\u5806\u6808\u5927\u5c0f\u4e3a256K.\u66f4\u5177\u5e94\u7528\u7684\u7ebf\u7a0b\u6240\u9700\u5185\u5b58\u5927\u5c0f\u8fdb\u884c \u8c03\u6574.\u5728\u76f8\u540c\u7269\u7406\u5185\u5b58\u4e0b,\u51cf\u5c0f\u8fd9\u4e2a\u503c\u80fd\u751f\u6210\u66f4\u591a\u7684\u7ebf\u7a0b.\u4f46\u662f\u64cd\u4f5c\u7cfb\u7edf\u5bf9\u4e00\u4e2a\u8fdb\u7a0b\u5185\u7684\u7ebf\u7a0b\u6570\u8fd8\u662f\u6709\u9650\u5236\u7684,\u4e0d\u80fd\u65e0\u9650\u751f\u6210,\u7ecf\u9a8c\u503c\u57283000~5000\u5de6\u53f3
\u4e00\u822c\u5c0f\u7684\u5e94\u7528\uff0c \u5982\u679c\u6808\u4e0d\u662f\u5f88\u6df1\uff0c \u5e94\u8be5\u662f128k\u591f\u7528\u7684 \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\uff08\u6821\u957f\uff09
\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:\"\u201d
-Xss is translated in a VM flag named ThreadStackSize\u201d
\u4e00\u822c\u8bbe\u7f6e\u8fd9\u4e2a\u503c\u5c31\u53ef\u4ee5\u4e86\u3002<\/td>\n<\/tr>\n
-XX:ThreadStackSize<\/em><\/td>\nThread Stack Size<\/td>\n <\/td>\n(0 means use default stack size) [Sparc: 512; Solaris x86: 320 (was 256 prior in 5.0 and earlier); Sparc 64 bit: 1024; Linux amd64: 1024 (was 0 in 5.0 and earlier); all others 0.]<\/td>\n<\/tr>\n
-XX:NewRatio<\/td>\n\u5e74\u8f7b\u4ee3(\u5305\u62ecEden\u548c\u4e24\u4e2aSurvivor\u533a)\u4e0e\u5e74\u8001\u4ee3\u7684\u6bd4\u503c(\u9664\u53bb\u6301\u4e45\u4ee3)<\/td>\n <\/td>\n-XX:NewRatio=4\u8868\u793a\u5e74\u8f7b\u4ee3\u4e0e\u5e74\u8001\u4ee3\u6240\u5360\u6bd4\u503c\u4e3a1:4,\u5e74\u8f7b\u4ee3\u5360\u6574\u4e2a\u5806\u6808\u76841\/5
Xms=Xmx\u5e76\u4e14\u8bbe\u7f6e\u4e86Xmn\u7684\u60c5\u51b5\u4e0b\uff0c\u8be5\u53c2\u6570\u4e0d\u9700\u8981\u8fdb\u884c\u8bbe\u7f6e\u3002<\/td>\n<\/tr>\n
-XX:SurvivorRatio<\/td>\nEden\u533a\u4e0eSurvivor\u533a\u7684\u5927\u5c0f\u6bd4\u503c<\/td>\n <\/td>\n\u8bbe\u7f6e\u4e3a8,\u5219\u4e24\u4e2aSurvivor\u533a\u4e0e\u4e00\u4e2aEden\u533a\u7684\u6bd4\u503c\u4e3a2:8,\u4e00\u4e2aSurvivor\u533a\u5360\u6574\u4e2a\u5e74\u8f7b\u4ee3\u76841\/10<\/td>\n<\/tr>\n
-XX:LargePageSizeInBytes<\/td>\n\u5185\u5b58\u9875\u7684\u5927\u5c0f\u4e0d\u53ef\u8bbe\u7f6e\u8fc7\u5927\uff0c \u4f1a\u5f71\u54cdPerm\u7684\u5927\u5c0f<\/td>\n <\/td>\n=128m<\/td>\n<\/tr>\n
-XX:+UseFastAccessorMethods<\/td>\n\u539f\u59cb\u7c7b\u578b\u7684\u5feb\u901f\u4f18\u5316<\/td>\n <\/td>\n <\/td>\n<\/tr>\n
-XX:+DisableExplicitGC<\/td>\n\u5173\u95edSystem.gc()<\/td>\n <\/td>\n\u8fd9\u4e2a\u53c2\u6570\u9700\u8981\u4e25\u683c\u7684\u6d4b\u8bd5<\/td>\n<\/tr>\n
-XX:MaxTenuringThreshold<\/td>\n\u5783\u573e\u6700\u5927\u5e74\u9f84<\/td>\n <\/td>\n\u5982\u679c\u8bbe\u7f6e\u4e3a0\u7684\u8bdd,\u5219\u5e74\u8f7b\u4ee3\u5bf9\u8c61\u4e0d\u7ecf\u8fc7Survivor\u533a,\u76f4\u63a5\u8fdb\u5165\u5e74\u8001\u4ee3. \u5bf9\u4e8e\u5e74\u8001\u4ee3\u6bd4\u8f83\u591a\u7684\u5e94\u7528,\u53ef\u4ee5\u63d0\u9ad8\u6548\u7387.\u5982\u679c\u5c06\u6b64\u503c\u8bbe\u7f6e\u4e3a\u4e00\u4e2a\u8f83\u5927\u503c,\u5219\u5e74\u8f7b\u4ee3\u5bf9\u8c61\u4f1a\u5728Survivor\u533a\u8fdb\u884c\u591a\u6b21\u590d\u5236,\u8fd9\u6837\u53ef\u4ee5\u589e\u52a0\u5bf9\u8c61\u518d\u5e74\u8f7b\u4ee3\u7684\u5b58\u6d3b \u65f6\u95f4,\u589e\u52a0\u5728\u5e74\u8f7b\u4ee3\u5373\u88ab\u56de\u6536\u7684\u6982\u7387
\u8be5\u53c2\u6570\u53ea\u6709\u5728\u4e32\u884cGC\u65f6\u624d\u6709\u6548.<\/td>\n<\/tr>\n
-XX:+AggressiveOpts<\/td>\n\u52a0\u5feb\u7f16\u8bd1<\/td>\n <\/td>\n <\/td>\n<\/tr>\n
-XX:+UseBiasedLocking<\/td>\n\u9501\u673a\u5236\u7684\u6027\u80fd\u6539\u5584<\/td>\n <\/td>\n <\/td>\n<\/tr>\n
-Xnoclassgc<\/td>\n\u7981\u7528\u5783\u573e\u56de\u6536<\/td>\n <\/td>\n <\/td>\n<\/tr>\n
-XX:SoftRefLRUPolicyMSPerMB<\/td>\n\u6bcf\u5146\u5806\u7a7a\u95f2\u7a7a\u95f4\u4e2dSoftReference\u7684\u5b58\u6d3b\u65f6\u95f4<\/td>\n1s<\/td>\nsoftly reachable objects will remain alive for some amount of time after the last time they were referenced. The default value is one second of lifetime per free megabyte in the heap<\/td>\n<\/tr>\n
-XX:PretenureSizeThreshold<\/td>\n\u5bf9\u8c61\u8d85\u8fc7\u591a\u5927\u662f\u76f4\u63a5\u5728\u65e7\u751f\u4ee3\u5206\u914d<\/td>\n0<\/td>\n\u5355\u4f4d\u5b57\u8282 \u65b0\u751f\u4ee3\u91c7\u7528Parallel Scavenge GC\u65f6\u65e0\u6548
\u53e6\u4e00\u79cd\u76f4\u63a5\u5728\u65e7\u751f\u4ee3\u5206\u914d\u7684\u60c5\u51b5\u662f\u5927\u7684\u6570\u7ec4\u5bf9\u8c61,\u4e14\u6570\u7ec4\u4e2d\u65e0\u5916\u90e8\u5f15\u7528\u5bf9\u8c61.<\/td>\n<\/tr>\n
-XX:TLABWasteTargetPercent<\/td>\nTLAB\u5360eden\u533a\u7684\u767e\u5206\u6bd4<\/td>\n1%<\/td>\n <\/td>\n<\/tr>\n
-XX:+CollectGen0First<\/em><\/td>\nFullGC\u65f6\u662f\u5426\u5148YGC<\/td>\nfalse<\/td>\n <\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

\u5e76\u884c\u6536\u96c6\u5668\u76f8\u5173\u53c2\u6570<\/strong><\/p>\n

\n\n\n\n\n\n\n\n\n\n\n
-XX:+UseParallelGC<\/td>\nFull GC\u91c7\u7528parallel MSC
(\u6b64\u9879\u5f85\u9a8c\u8bc1)<\/td>\n		 <\/td>\n\n

\u9009\u62e9\u5783\u573e\u6536\u96c6\u5668\u4e3a\u5e76\u884c\u6536\u96c6\u5668.\u6b64\u914d\u7f6e\u4ec5\u5bf9\u5e74\u8f7b\u4ee3\u6709\u6548.\u5373\u4e0a\u8ff0\u914d\u7f6e\u4e0b,\u5e74\u8f7b\u4ee3\u4f7f\u7528\u5e76\u53d1\u6536\u96c6,\u800c\u5e74\u8001\u4ee3\u4ecd\u65e7\u4f7f\u7528\u4e32\u884c\u6536\u96c6.(\u6b64\u9879\u5f85\u9a8c\u8bc1)<\/p>\n<\/td>\n<\/tr>\n

-XX:+UseParNewGC<\/td>\n\u8bbe\u7f6e\u5e74\u8f7b\u4ee3\u4e3a\u5e76\u884c\u6536\u96c6<\/td>\n <\/td>\n\u53ef\u4e0eCMS\u6536\u96c6\u540c\u65f6\u4f7f\u7528
JDK5.0\u4ee5\u4e0a,JVM\u4f1a\u6839\u636e\u7cfb\u7edf\u914d\u7f6e\u81ea\u884c\u8bbe\u7f6e,\u6240\u4ee5\u65e0\u9700\u518d\u8bbe\u7f6e\u6b64\u503c<\/td>\n<\/tr>\n
-XX:ParallelGCThreads<\/td>\n\u5e76\u884c\u6536\u96c6\u5668\u7684\u7ebf\u7a0b\u6570<\/td>\n <\/td>\n\u6b64\u503c\u6700\u597d\u914d\u7f6e\u4e0e\u5904\u7406\u5668\u6570\u76ee\u76f8\u7b49 \u540c\u6837\u9002\u7528\u4e8eCMS<\/td>\n<\/tr>\n
-XX:+UseParallelOldGC<\/td>\n\u5e74\u8001\u4ee3\u5783\u573e\u6536\u96c6\u65b9\u5f0f\u4e3a\u5e76\u884c\u6536\u96c6(Parallel Compacting)<\/td>\n <\/td>\n\u8fd9\u4e2a\u662fJAVA 6\u51fa\u73b0\u7684\u53c2\u6570\u9009\u9879<\/td>\n<\/tr>\n
-XX:MaxGCPauseMillis<\/td>\n\u6bcf\u6b21\u5e74\u8f7b\u4ee3\u5783\u573e\u56de\u6536\u7684\u6700\u957f\u65f6\u95f4(\u6700\u5927\u6682\u505c\u65f6\u95f4)<\/td>\n <\/td>\n\u5982\u679c\u65e0\u6cd5\u6ee1\u8db3\u6b64\u65f6\u95f4,JVM\u4f1a\u81ea\u52a8\u8c03\u6574\u5e74\u8f7b\u4ee3\u5927\u5c0f,\u4ee5\u6ee1\u8db3\u6b64\u503c.<\/td>\n<\/tr>\n
-XX:+UseAdaptiveSizePolicy<\/td>\n\u81ea\u52a8\u9009\u62e9\u5e74\u8f7b\u4ee3\u533a\u5927\u5c0f\u548c\u76f8\u5e94\u7684Survivor\u533a\u6bd4\u4f8b<\/td>\n <\/td>\n\u8bbe\u7f6e\u6b64\u9009\u9879\u540e,\u5e76\u884c\u6536\u96c6\u5668\u4f1a\u81ea\u52a8\u9009\u62e9\u5e74\u8f7b\u4ee3\u533a\u5927\u5c0f\u548c\u76f8\u5e94\u7684Survivor\u533a\u6bd4\u4f8b,\u4ee5\u8fbe\u5230\u76ee\u6807\u7cfb\u7edf\u89c4\u5b9a\u7684\u6700\u4f4e\u76f8\u5e94\u65f6\u95f4\u6216\u8005\u6536\u96c6\u9891\u7387\u7b49,\u6b64\u503c\u5efa\u8bae\u4f7f\u7528\u5e76\u884c\u6536\u96c6\u5668\u65f6,\u4e00\u76f4\u6253\u5f00.<\/td>\n<\/tr>\n
-XX:GCTimeRatio<\/td>\n\u8bbe\u7f6e\u5783\u573e\u56de\u6536\u65f6\u95f4\u5360\u7a0b\u5e8f\u8fd0\u884c\u65f6\u95f4\u7684\u767e\u5206\u6bd4<\/td>\n <\/td>\n\u516c\u5f0f\u4e3a1\/(1+n)<\/td>\n<\/tr>\n
-XX:+ScavengeBeforeFullGC<\/em><\/td>\nFull GC\u524d\u8c03\u7528YGC<\/td>\ntrue<\/td>\nDo young generation GC prior to a full GC. (Introduced in 1.4.1.)<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

CMS\u76f8\u5173\u53c2\u6570<\/strong><\/p>\n

\n\n\n\n\n\n\n\n\n\n\n\n\n
-XX:+UseConcMarkSweepGC<\/td>\n\u4f7f\u7528CMS\u5185\u5b58\u6536\u96c6<\/td>\n <\/td>\n\u6d4b\u8bd5\u4e2d\u914d\u7f6e\u8fd9\u4e2a\u4ee5\u540e,-XX:NewRatio=4\u7684\u914d\u7f6e\u5931\u6548\u4e86,\u539f\u56e0\u4e0d\u660e.\u6240\u4ee5,\u6b64\u65f6\u5e74\u8f7b\u4ee3\u5927\u5c0f\u6700\u597d\u7528-Xmn\u8bbe\u7f6e.???<\/td>\n<\/tr>\n
-XX:+AggressiveHeap<\/td>\n <\/td>\n <\/td>\n\u8bd5\u56fe\u662f\u4f7f\u7528\u5927\u91cf\u7684\u7269\u7406\u5185\u5b58
\u957f\u65f6\u95f4\u5927\u5185\u5b58\u4f7f\u7528\u7684\u4f18\u5316\uff0c\u80fd\u68c0\u67e5\u8ba1\u7b97\u8d44\u6e90\uff08\u5185\u5b58\uff0c \u5904\u7406\u5668\u6570\u91cf\uff09
\u81f3\u5c11\u9700\u8981256MB\u5185\u5b58
\u5927\u91cf\u7684CPU\uff0f\u5185\u5b58\uff0c \uff08\u57281.4.1\u57284CPU\u7684\u673a\u5668\u4e0a\u5df2\u7ecf\u663e\u793a\u6709\u63d0\u5347\uff09<\/td>\n<\/tr>\n
-XX:CMSFullGCsBeforeCompaction<\/td>\n\u591a\u5c11\u6b21\u540e\u8fdb\u884c\u5185\u5b58\u538b\u7f29<\/td>\n <\/td>\n\u7531\u4e8e\u5e76\u53d1\u6536\u96c6\u5668\u4e0d\u5bf9\u5185\u5b58\u7a7a\u95f4\u8fdb\u884c\u538b\u7f29,\u6574\u7406,\u6240\u4ee5\u8fd0\u884c\u4e00\u6bb5\u65f6\u95f4\u4ee5\u540e\u4f1a\u4ea7\u751f\"\u788e\u7247\",\u4f7f\u5f97\u8fd0\u884c\u6548\u7387\u964d\u4f4e.\u6b64\u503c\u8bbe\u7f6e\u8fd0\u884c\u591a\u5c11\u6b21GC\u4ee5\u540e\u5bf9\u5185\u5b58\u7a7a\u95f4\u8fdb\u884c\u538b\u7f29,\u6574\u7406.<\/td>\n<\/tr>\n
-XX:+CMSParallelRemarkEnabled<\/td>\n\u964d\u4f4e\u6807\u8bb0\u505c\u987f<\/td>\n <\/td>\n <\/td>\n<\/tr>\n
-XX+UseCMSCompactAtFullCollection<\/td>\n\u5728FULL GC\u7684\u65f6\u5019\uff0c \u5bf9\u5e74\u8001\u4ee3\u7684\u538b\u7f29<\/td>\n <\/td>\nCMS\u662f\u4e0d\u4f1a\u79fb\u52a8\u5185\u5b58\u7684\uff0c \u56e0\u6b64\uff0c \u8fd9\u4e2a\u975e\u5e38\u5bb9\u6613\u4ea7\u751f\u788e\u7247\uff0c \u5bfc\u81f4\u5185\u5b58\u4e0d\u591f\u7528\uff0c \u56e0\u6b64\uff0c \u5185\u5b58\u7684\u538b\u7f29\u8fd9\u4e2a\u65f6\u5019\u5c31\u4f1a\u88ab\u542f\u7528\u3002 \u589e\u52a0\u8fd9\u4e2a\u53c2\u6570\u662f\u4e2a\u597d\u4e60\u60ef\u3002
\u53ef\u80fd\u4f1a\u5f71\u54cd\u6027\u80fd,\u4f46\u662f\u53ef\u4ee5\u6d88\u9664\u788e\u7247<\/td>\n<\/tr>\n
-XX:+UseCMSInitiatingOccupancyOnly<\/td>\n\u4f7f\u7528\u624b\u52a8\u5b9a\u4e49\u521d\u59cb\u5316\u5b9a\u4e49\u5f00\u59cbCMS\u6536\u96c6<\/td>\n <\/td>\n\u7981\u6b62hostspot\u81ea\u884c\u89e6\u53d1CMS GC<\/td>\n<\/tr>\n
-XX:CMSInitiatingOccupancyFraction=70<\/td>\n\u4f7f\u7528cms\u4f5c\u4e3a\u5783\u573e\u56de\u6536
\u4f7f\u752870\uff05\u540e\u5f00\u59cbCMS\u6536\u96c6<\/td>\n		92<\/td>\n\u4e3a\u4e86\u4fdd\u8bc1\u4e0d\u51fa\u73b0promotion failed(\u89c1\u4e0b\u9762\u4ecb\u7ecd)\u9519\u8bef,\u8be5\u503c\u7684\u8bbe\u7f6e\u9700\u8981\u6ee1\u8db3\u4ee5\u4e0b\u516c\u5f0fCMSInitiatingOccupancyFraction\u8ba1\u7b97\u516c\u5f0f<\/a><\/strong><\/td>\n<\/tr>\n
-XX:CMSInitiatingPermOccupancyFraction<\/td>\n\u8bbe\u7f6ePerm Gen\u4f7f\u7528\u5230\u8fbe\u591a\u5c11\u6bd4\u7387\u65f6\u89e6\u53d1<\/td>\n92<\/td>\n <\/td>\n<\/tr>\n
-XX:+CMSIncrementalMode<\/td>\n\u8bbe\u7f6e\u4e3a\u589e\u91cf\u6a21\u5f0f <\/td>\n <\/td>\n\u7528\u4e8e\u5355CPU\u60c5\u51b5<\/td>\n<\/tr>\n
-XX:+CMSClassUnloadingEnabled<\/td>\n <\/td>\n <\/td>\n <\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

\u8f85\u52a9\u4fe1\u606f<\/strong><\/p>\n

\n\n\n\n\n\n\n\n\n\n\n\n\n\n
-XX:+PrintGC<\/td>\n <\/td>\n <\/td>\n\n

\u8f93\u51fa\u5f62\u5f0f:<\/p>\n

[GC 118250K->113543K(130112K), 0.0094143 secs]
[Full GC 121376K->10414K(130112K), 0.0650971 secs]<\/p>\n<\/td>\n<\/tr>\n

-XX:+PrintGCDetails<\/td>\n <\/td>\n <\/td>\n\n

\u8f93\u51fa\u5f62\u5f0f:[GC [DefNew: 8614K->781K(9088K), 0.0123035 secs] 118250K->113543K(130112K), 0.0124633 secs]
[GC [DefNew: 8614K->8614K(9088K), 0.0000665 secs][Tenured: 112761K->10414K(121024K), 0.0433488 secs] 121376K->10414K(130112K), 0.0436268 secs]<\/p>\n<\/td>\n<\/tr>\n

-XX:+PrintGCTimeStamps<\/td>\n <\/td>\n <\/td>\n <\/td>\n<\/tr>\n
-XX:+PrintGC:PrintGCTimeStamps<\/td>\n <\/td>\n <\/td>\n\u53ef\u4e0e-XX:+PrintGC -XX:+PrintGCDetails\u6df7\u5408\u4f7f\u7528
\u8f93\u51fa\u5f62\u5f0f:11.851: [GC 98328K->93620K(130112K), 0.0082960 secs]<\/td>\n<\/tr>\n
-XX:+PrintGCApplicationStoppedTime<\/td>\n\u6253\u5370\u5783\u573e\u56de\u6536\u671f\u95f4\u7a0b\u5e8f\u6682\u505c\u7684\u65f6\u95f4.\u53ef\u4e0e\u4e0a\u9762\u6df7\u5408\u4f7f\u7528<\/td>\n <\/td>\n\u8f93\u51fa\u5f62\u5f0f:Total time for which application threads were stopped: 0.0468229 seconds<\/td>\n<\/tr>\n
-XX:+PrintGCApplicationConcurrentTime<\/td>\n\u6253\u5370\u6bcf\u6b21\u5783\u573e\u56de\u6536\u524d,\u7a0b\u5e8f\u672a\u4e2d\u65ad\u7684\u6267\u884c\u65f6\u95f4.\u53ef\u4e0e\u4e0a\u9762\u6df7\u5408\u4f7f\u7528<\/td>\n <\/td>\n\u8f93\u51fa\u5f62\u5f0f:Application time: 0.5291524 seconds<\/td>\n<\/tr>\n
-XX:+PrintHeapAtGC<\/td>\n\u6253\u5370GC\u524d\u540e\u7684\u8be6\u7ec6\u5806\u6808\u4fe1\u606f<\/td>\n <\/td>\n <\/td>\n<\/tr>\n
-Xloggc:filename<\/td>\n\u628a\u76f8\u5173\u65e5\u5fd7\u4fe1\u606f\u8bb0\u5f55\u5230\u6587\u4ef6\u4ee5\u4fbf\u5206\u6790.
\u4e0e\u4e0a\u9762\u51e0\u4e2a\u914d\u5408\u4f7f\u7528<\/td>\n		 <\/td>\n <\/td>\n<\/tr>\n
\n

-XX:+PrintClassHistogram<\/p>\n<\/td>\n

garbage collects before printing the histogram.<\/td>\n <\/td>\n <\/td>\n<\/tr>\n
-XX:+PrintTLAB<\/td>\n\u67e5\u770bTLAB\u7a7a\u95f4\u7684\u4f7f\u7528\u60c5\u51b5<\/td>\n <\/td>\n <\/td>\n<\/tr>\n
XX:+PrintTenuringDistribution<\/td>\n\u67e5\u770b\u6bcf\u6b21minor GC\u540e\u65b0\u7684\u5b58\u6d3b\u5468\u671f\u7684\u9608\u503c<\/td>\n <\/td>\n\n

Desired survivor size 1048576 bytes, new threshold 7 (max 15)
new threshold 7\u5373\u6807\u8bc6\u65b0\u7684\u5b58\u6d3b\u5468\u671f\u7684\u9608\u503c\u4e3a7\u3002<\/p>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

GC\u6027\u80fd\u65b9\u9762\u7684\u8003\u8651<\/strong><\/p>\n

       \u5bf9\u4e8eGC\u7684\u6027\u80fd\u4e3b\u8981\u67092\u4e2a\u65b9\u9762\u7684\u6307\u6807\uff1a\u541e\u5410\u91cfthroughput\uff08\u5de5\u4f5c\u65f6\u95f4\u4e0d\u7b97gc\u7684\u65f6\u95f4\u5360\u603b\u7684\u65f6\u95f4\u6bd4\uff09\u548c\u6682\u505cpause\uff08gc\u53d1\u751f\u65f6app\u5bf9\u5916\u663e\u793a\u7684\u65e0\u6cd5\u54cd\u5e94\uff09\u3002<\/p>\n

1. Total Heap <\/p>\n

       \u9ed8\u8ba4\u60c5\u51b5\u4e0b\uff0cvm\u4f1a\u589e\u52a0\/\u51cf\u5c11heap\u5927\u5c0f\u4ee5\u7ef4\u6301free space\u5728\u6574\u4e2avm\u4e2d\u5360\u7684\u6bd4\u4f8b\uff0c\u8fd9\u4e2a\u6bd4\u4f8b\u7531MinHeapFreeRatio\u548cMaxHeapFreeRatio\u6307\u5b9a\u3002 <\/p>\n

\u4e00\u822c\u800c\u8a00\uff0cserver\u7aef\u7684app\u4f1a\u6709\u4ee5\u4e0b\u89c4\u5219\uff1a <\/p>\n