{"id":1936,"date":"2019-09-16T08:01:13","date_gmt":"2019-09-16T00:01:13","guid":{"rendered":"https:\/\/coderbee.net\/?p=1936"},"modified":"2019-09-15T22:51:32","modified_gmt":"2019-09-15T14:51:32","slug":"jvm-%e5%a0%86%e5%a4%96%e5%86%85%e5%ad%98%e6%b3%84%e6%bc%8f%e5%88%86%e6%9e%90%ef%bc%88%e4%ba%8c%ef%bc%89","status":"publish","type":"post","link":"https:\/\/coderbee.net\/index.php\/jvm\/20190916\/1936","title":{"rendered":"JVM \u5806\u5916\u5185\u5b58\u6cc4\u6f0f\u5206\u6790\uff08\u4e8c\uff09"},"content":{"rendered":"

\u5173\u4e8e \u5806\u5916\u5185\u5b58\u7684\u7ec4\u6210\u53ef\u4ee5\u770b\u4e0a\u4e00\u7bc7\u6587\u7ae0 JVM \u5806\u5916\u5185\u5b58\u6cc4\u6f0f\u5206\u6790\uff08\u4e00\uff09<\/a><\/p>\n

1. NMT<\/h1>\n

NMT\uff08Native Memory Tracking\uff09\u662f HotSpot JVM \u5f15\u5165\u7684\u8ddf\u8e2a JVM \u5185\u90e8\u4f7f\u7528\u7684\u672c\u5730\u5185\u5b58\u7684\u4e00\u4e2a\u7279\u6027\uff0c\u53ef\u4ee5\u901a\u8fc7 jcmd \u5de5\u5177\u8bbf\u95ee NMT \u6570\u636e\u3002NMT \u76ee\u524d\u4e0d\u652f\u6301\u8ddf\u8e2a\u7b2c\u4e09\u65b9\u672c\u5730\u4ee3\u7801\u7684\u5185\u5b58\u5206\u914d\u548c JDK \u7c7b\u5e93\u3002<\/p>\n

NMT \u4e0d\u8ddf\u8e2a\u975e JVM \u4ee3\u7801\u7684\u5185\u5b58\u5206\u914d\uff0c\u672c\u5730\u4ee3\u7801\u91cc\u7684\u5185\u5b58\u6cc4\u9732\u9700\u8981\u4f7f\u7528\u64cd\u4f5c\u7cfb\u7edf\u652f\u6301\u7684\u5de5\u5177\u6765\u5b9a\u4f4d\u3002<\/p>\n

1.1 \u5f00\u542f NMT<\/h2>\n

\u542f\u7528 NMT \u4f1a\u5e26\u6765 5-10% \u7684\u6027\u80fd\u635f\u5931\u3002NMT \u7684\u5185\u5b58\u4f7f\u7528\u7387\u60c5\u51b5\u9700\u8981\u6dfb\u52a0\u4e24\u4e2a\u673a\u5668\u5b57 word \u5230 malloc \u5185\u5b58\u7684 malloc \u5934\u91cc\u3002NMT \u5185\u5b58\u4f7f\u7528\u7387\u4e5f\u88ab NMT \u8ddf\u8e2a\u3002<\/p>\n

\u542f\u52a8\u547d\u4ee4\uff1a -XX:NativeMemoryTracking=[off | summary | detail]<\/code>\u3002<\/p>\n

\n

off\uff1aNMT \u9ed8\u8ba4\u662f\u5173\u95ed\u7684\uff1b
\n summary\uff1a\u53ea\u6536\u96c6\u5b50\u7cfb\u7edf\u7684\u5185\u5b58\u4f7f\u7528\u7684\u603b\u8ba1\u6570\u636e\uff1b
\n detail\uff1a\u6536\u96c6\u6bcf\u4e2a\u8c03\u7528\u70b9\u7684\u5185\u5b58\u4f7f\u7528\u6570\u636e\u3002<\/p>\n<\/blockquote>\n

1.2 jcmd \u8bbf\u95ee NMT \u6570\u636e<\/h2>\n

\u547d\u4ee4\uff1a jcmd <pid> VM.native_memory [summary | detail | baseline | summary.diff | detail.diff | shutdown] [scale= KB | MB | GB]<\/code><\/p>\n\n\n\n\n\n\n\n\n\n\n
option<\/th>\ndesc<\/th>\n<\/tr>\n<\/thead>\n
summary<\/td>\n\u6309\u5206\u7c7b\u6253\u5370\u6c47\u603b\u6570\u636e<\/td>\n<\/tr>\n
detail<\/td>\n\u6309\u5206\u7c7b\u6253\u5370\u6c47\u603b\u6570\u636e
\u6253\u5370\u865a\u62df\u5185\u5b58\u6620\u5c04
\u6309\u8c03\u7528\u70b9\u6253\u5370\u5185\u5b58\u4f7f\u7528\u6c47\u603b<\/td>\n<\/tr>\n
baseling<\/td>\n\u521b\u5efa\u5185\u5b58\u4f7f\u7528\u5feb\u7167\u7528\u4e8e\u540e\u7eed\u5bf9\u6bd4<\/td>\n<\/tr>\n
summary.diff<\/td>\n\u57fa\u4e8e\u6700\u65b0\u7684\u57fa\u7ebf\u6253\u5370\u4e00\u4efd\u6c47\u603b\u62a5\u544a<\/td>\n<\/tr>\n
detail.diff<\/td>\n\u57fa\u4e8e\u6700\u65b0\u7684\u57fa\u7ebf\u6253\u5370\u4e00\u4efd\u660e\u7ec6\u62a5\u544a<\/td>\n<\/tr>\n
shutdown<\/td>\n\u5173\u95ed NMT<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\u5728 NMT \u542f\u7528\u7684\u60c5\u51b5\u4e0b\uff0c\u53ef\u4ee5\u901a\u8fc7\u4e0b\u9762\u7684\u547d\u4ee4\u884c\u9009\u9879\u5728 JVM \u9000\u51fa\u65f6\u8f93\u51fa\u6700\u540e\u7684\u5185\u5b58\u4f7f\u7528\u6570\u636e\uff1a
\n-XX:+UnlockDiagnosticVMOptions -XX:+PrintNMTStatistics<\/code><\/p>\n

<\/p>\n

1.3 \u4f7f\u7528 NMT \u68c0\u6d4b\u5185\u5b58\u6cc4\u9732<\/h2>\n
    \n
  1. \u5f00\u542f NMT\uff0c\u7528\u547d\u4ee4\uff1a -XX:NativeMemoryTracking=summary|detail<\/code><\/li>\n
  2. \u521b\u5efa\u57fa\u7ebf\uff0c\u7528\u547d\u4ee4\uff1a jcmd <pid> VM.native_memory baseline<\/code><\/li>\n
  3. \u89c2\u5bdf\u5185\u5b58\u53d8\u5316\uff1a jcmd <pid> VM.native_memory detail.diff<\/code><\/li>\n<\/ol>\n

    NMT \u6570\u636e\u8f93\u51fa\u89e3\u91ca\uff1a<\/p>\n

    reserved memory\uff1a\u9884\u8ba2\u5185\u5b58\uff0c\u4e0d\u8868\u793a\u5b9e\u9645\u4f7f\u7528\uff0c\u6700\u4e3b\u8981\u7684\u662f\u7533\u8bf7\u4e86\u4e00\u6279\u8fde\u7eed\u7684\u5730\u5740\u7a7a\u95f4\uff1b\uff08OS \u89d2\u5ea6\uff09
    \ncommited memory\uff1a\u5b9e\u9645\u4f7f\u7528\u7684\u3002\uff08OS \u89d2\u5ea6\uff09
    \n\u5bf9\u4e8e 64 \u4f4d\u7684\u7cfb\u7edf\uff0c\u5730\u5740\u7a7a\u95f4\u51e0\u4e4e\u662f\u65e0\u9650\u7684\uff0c\u4f46\u8d8a\u6765\u8d8a\u591a\u7684\u5185\u5b58 committed\uff0c\u53ef\u80fd\u4f1a\u5bfc\u81f4 swapping \u6216\u672c\u5730 OOM \u3002<\/p>\n

    \u4ee5\u4e0b\u793a\u4f8b\u6765\u81ea https:\/\/docs.oracle.com\/javase\/8\/docs\/technotes\/guides\/troubleshoot\/tooldescr007.html<\/a> \u3002<\/p>\n

    -XX:NativeMemoryTracking=summary<\/code> \u4e0e jcmd <pid> VM.native_memory summary<\/code> \u8f93\u51fa\uff1a<\/p>\n

    Total:  reserved=664192KB,  committed=253120KB  <--- total memory tracked by Native Memory Tracking\n\n-     Java Heap (reserved=516096KB, committed=204800KB)  <--- Java Heap\n                (mmap: reserved=516096KB, committed=204800KB)\n\n-     Class (reserved=6568KB, committed=4140KB)     <--- class metadata\n            (classes #665)                          <--- number of loaded classes\n            (malloc=424KB, #1000)                   <--- malloc'd memory, #number of malloc\n            (mmap: reserved=6144KB, committed=3716KB)\n\n-     Thread (reserved=6868KB, committed=6868KB)\n            (thread #15)                            <--- number of threads\n            (stack: reserved=6780KB, committed=6780KB) <--- memory used by thread stacks\n            (malloc=27KB, #66)\n            (arena=61KB, #30)                       <--- resource and handle areas\n\n-     Code (reserved=102414KB, committed=6314KB)\n           (malloc=2574KB, #74316)\n           (mmap: reserved=99840KB, committed=3740KB)\n\n-     GC (reserved=26154KB, committed=24938KB)\n           (malloc=486KB, #110)\n           (mmap: reserved=25668KB, committed=24452KB)\n\n-     Compiler (reserved=106KB, committed=106KB)\n               (malloc=7KB, #90)\n               (arena=99KB, #3)\n\n-     Internal (reserved=586KB, committed=554KB)\n               (malloc=554KB, #1677)\n               (mmap: reserved=32KB, committed=0KB)\n\n-     Symbol (reserved=906KB, committed=906KB)\n             (malloc=514KB, #2736)\n             (arena=392KB, #1)\n\n-     Memory Tracking (reserved=3184KB, committed=3184KB)\n                      (malloc=3184KB, #300)\n\n-     Pooled Free Chunks (reserved=1276KB, committed=1276KB)\n                         (malloc=1276KB)\n\n-     Unknown (reserved=33KB, committed=33KB)\n              (arena=33KB, #1)\n<\/code><\/pre>\n
    -XX:NativeMemoryTracking=detail<\/code> \u4e0e jcmd <pid> VM.native_memory detail<\/code> \u7ec4\u5408\u7684\u8f93\u51fa\u793a\u4f8b\uff1a<\/p>\n
    2. \u7cfb\u7edf\u5c42\u9762\u7684\u5206\u6790\u601d\u8def<\/h1>\n
    \u5185\u5b58\u6cc4\u6f0f\u4e00\u822c\u90fd\u4e0d\u662f\u7a81\u7136\u731b\u589e\u5230\u6781\u9650\uff0c\u800c\u662f\u4e00\u4e2a\u6162\u6162\u589e\u957f\u7684\u8fc7\u7a0b\uff0c\u8fd9\u6837\u6211\u4eec\u53ef\u4ee5\u9009\u53d6\u4e24\u4e2a\u65f6\u95f4\u7684\u5185\u5b58\u6765\u8fdb\u884c\u5bf9\u6bd4\uff0c\u770b\u65b0\u589e\u7684\u5185\u5b58\u91cc\u5230\u5e95\u5b58\u7684\u662f\u4ec0\u4e48\u5185\u5bb9\u3002<\/p>\n
    2.0 gdb \u65b9\u5f0f<\/h2>\n
    gdb \u5bfc\u51fa\u6307\u5b9a\u5730\u5740\u8303\u56f4\u7684\u5185\u5b58\u5757\u7684\u5185\u5bb9 \uff1a<\/p>\n
    sudo gdb --batch --pid 2754 -ex \"dump memory a.dump 0x7f1023ff6000 0x7f1023ff6000+268435456\"\n<\/code><\/pre>\n
    \u7136\u540e\u7528 hexdump -C \/tmp\/memory.bin<\/code> \u6216 strings \/tmp\/memory.bin |less<\/code> \u67e5\u770b\u5185\u5b58\u5757\u91cc\u7684\u5185\u5bb9\u3002<\/p>\n
    \u5982\u679c\u5185\u5b58\u5757\u91cc\u5b58\u7684\u662f\u6587\u672c\u4fe1\u606f\uff0c\u8fd9\u6837\u662f\u53ef\u4ee5\u770b\u51fa\u5b58\u7684\u662f\u4ec0\u4e48\u5185\u5bb9\u7684\uff0c\u5982\u679c\u662f\u4e8c\u8fdb\u5236\u7684\u5185\u5b58\uff0c\u5c31\u6ca1\u6cd5\u770b\u4e86\u3002<\/p>\n
    2.1 jstack\/jmap + core dump<\/h2>\n
    \u5148\u751f\u6210 core dump\uff0c\u7136\u540e\u4ece core dump \u91cc\u63d0\u53d6\u7ebf\u7a0b\u6808\u3001JVM \u5806 dump\uff0cJDK 8 \u4e0b\u63d0\u53d6\u6210\u529f\uff1a<\/p>\n
    # \u4f7f\u7528 gcore \u547d\u4ee4\u751f\u6210 core dump\uff0c\ngcore 1791\n\n# \u4f7f\u7528 jstack \u4ece core dump \u6587\u4ef6\u63d0\u53d6\u7ebf\u7a0b\u4fe1\u606f\n~\/zuul-jdk\/zulu8.40.0.25-ca-jdk8.0.222-linux_x64\/bin\/jstack ~\/zuul-jdk\/zulu8.40.0.25-ca-jdk8.0.222-linux_x64\/bin\/java core.1791\n\n# \u4f7f\u7528 jmap \u4ece core dump \u6587\u4ef6\u63d0\u53d6 JVM \u5806 dump\n~\/zuul-jdk\/zulu8.40.0.25-ca-jdk8.0.222-linux_x64\/bin\/jmap -dump:format=b,file=zuul.jmap.hprof ~\/zuul-jdk\/zulu8.40.0.25-ca-jdk8.0.222-linux_x64\/bin\/java core.1791\n\n# jstack\u3001jmap \u4ece core dump \u91cc\u63d0\u53d6\u4fe1\u606f\u7684\u65b9\u5f0f\uff0cexec \u4e00\u822c\u662f\u6307\u5411\u53ef\u6267\u884c\u547d\u4ee4 java \u7684\u8def\u5f84\njstack exec core-file\njmap <options> exec core-file\n<\/code><\/pre>\n
    2.2 jhsdb<\/h2>\n
    jhsdb\uff1a hsdb \u662f HotSpot debugger \u7684\u7b80\u79f0\uff0c\u662f JDK9 \u5f00\u59cb\u5f15\u5165\u7684\u4e00\u4e2a\u8c03\u8bd5\u5de5\u5177\u3002<\/p>\n
    $ jhsdb\n    clhsdb              command line debugger\n    hsdb                ui debugger\n    debugd --help       to get more information\n    jstack --help       to get more information\n    jmap   --help       to get more information\n    jinfo  --help       to get more information\n    jsnap  --help       to get more information\n<\/code><\/pre>\n
    \u5728 openJDK 11 \u63d0\u53d6\u5b9e\u64cd\u5931\u8d25\u4e86\uff0c\u751f\u6210\u5806 dump \u65f6\u4f1a\u51fa\u73b0\u4e00\u4e9b\u5185\u5b58\u5730\u5740\u8bfb\u53d6\u5931\u8d25\u3002<\/p>\n
    \u7528 jstack \u4ece core dump \u63d0\u53d6\u4fe1\u606f:<\/p>\n
    sudo jstack -J-d64 \/usr\/bin\/java core.2316\n\njhsdb jstack --exe \/usr\/bin\/java --core core.2316\n<\/code><\/pre>\n
    -d64<\/code> \u8868\u793a64\u4f4d\u7684\u7cfb\u7edf\uff0c\u8fd9\u4e24\u4e2a\u4e5f\u662f\u7f51\u4e0a\u627e\u7684\uff0c\u6ca1\u6709\u5b9e\u9645\u6210\u529f\u3002<\/p>\n
    3. \u53c2\u8003\u8d44\u6599<\/h1>\n