原文 http://weikeqin.com/2020/03/28/jvm-performance-tuning-monitoring-tool/
最近测试环境总是莫名的出问题，然后部署服务的容器里除了服务打印的日志，没有其它信息，想看看是什么原因导致服务很卡，是不是有哪块代码占用内存高。
代码执行缓慢、OutOfMemoryError，内存不足、内存泄露、线程死锁、锁争用（Lock Contention）、Java 进程消耗 CPU 过高 都可以使用 JDK 的命令行工具排查。
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(1) JDK 的命令行工具
jps、jstat、jinfo、jmap、jhat、jstack、hprof
jps : 虚拟机进程状况工具
jstat : 虚拟机统计信息监视工具
jinfo : Java 配置信息工具
jmap : Java 内存映像工具
jhat : 虚拟机堆转储快照分析工具
jstack : Java 堆栈跟踪工具
jps 将打印所有正在运行的 Java 进程。
jstat 允许用户查看目标 Java 进程的类加载、即时编译以及垃圾回收相关的信息。它常用于检测垃圾回收问题以及内存泄漏问题。
jmap 允许用户统计目标 Java 进程的堆中存放的 Java 对象，并将它们导出成二进制文件。
jinfo 将打印目标 Java 进程的配置参数，并能够改动其中 manageabe 的参数。
jstack 将打印目标 Java 进程中各个线程的栈轨迹、线程状态、锁状况等信息。它还将自动检测死锁。
jcmd 则是一把瑞士军刀，可以用来实现前面除了 jstat 之外所有命令的功能。
Java 虚拟机的监控及诊断工具-GUI
JConsole : Java 监视与管理控制台
VisualVM : 多合一故障处理工具
eclipse MAT
JMC
JITWatch
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(2) 虚拟机进程状况工具 jps (JVM Process Status Tool)
jps 主要用来输出 JVM 中运行的进程状态信息。
jps 命令使用 Java 启动器来查找传递给 main 方法的类名和参数。
[wkq@VM_77_25_centos ~]$ jps -helpusage: jps [-help] jps [-q] [-mlvV] [<hostid>]
Definitions: <hostid>: <hostname>[:<port>][wkq@VM_77_25_centos ~]$
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(2.1) jps 命令
jps 命令用于输出 JVM 中运行的进程状态信息。可以获取到进程的 pid、全限定名、传入 main 方法的参数、传入 JVM 的参数 等。
语法格式
jps [ options ] [ hostid ]
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如果不指定 hostid 就默认为当前主机或服务器。
详细信息见 man jps
(2.1.1) jps 不加参数
在本地主机上搜索检测到的 JVM。
[wkq@VM_77_25_centos ~]$ jps14916 Jps13050 Elasticsearch[wkq@VM_77_25_centos ~]$[wkq@VM_77_25_centos ~]$
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(2.1.2) jps -q
不输出类名、Jar 名和传入 main 方法的参数
[wkq@VM_77_25_centos ~]$ jps -q1505913050[wkq@VM_77_25_centos ~]$
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(2.1.3) jps -m
显示传递给 main 方法的参数。对于嵌入式 JVM，输出可能为 null。
[wkq@VM_77_25_centos ~]$ jps -m15092 Jps -m13050 Elasticsearch -d[wkq@VM_77_25_centos ~]$
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(2.1.4) jps -l
输出 main 类或 Jar 的全限定名
[wkq@VM_77_25_centos ~]$ jps -l15139 sun.tools.jps.Jps13050 org.elasticsearch.bootstrap.Elasticsearch[wkq@VM_77_25_centos ~]$
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(2.1.5) jps -v
显示传递给 JVM 的参数。
[wkq@VM_77_25_centos ~]$ jps -v15157 Jps -Denv.class.path=.:/home/wkq/software/jdk1.8.0_172/lib/dt.jar:/home/wkq/software/jdk1.8.0_172/lib/tools.jar -Dapplication.home=/home/wkq/software/jdk1.8.0_172 -Xms8m13050 Elasticsearch -Xms1g -Xmx1g -XX:+UseConcMarkSweepGC -XX:CMSInitiatingOccupancyFraction=75 -XX:+UseCMSInitiatingOccupancyOnly -Des.networkaddress.cache.ttl=60 -Des.networkaddress.cache.negative.ttl=10 -XX:+AlwaysPreTouch -Xss1m -Djava.awt.headless=true -Dfile.encoding=UTF-8 -Djna.nosys=true -XX:-OmitStackTraceInFastThrow -Dio.netty.noUnsafe=true -Dio.netty.noKeySetOptimization=true -Dio.netty.recycler.maxCapacityPerThread=0 -Dlog4j.shutdownHookEnabled=false -Dlog4j2.disable.jmx=true -Djava.io.tmpdir=/tmp/elasticsearch-5035355569386013893 -XX:+HeapDumpOnOutOfMemoryError -XX:HeapDumpPath=data -XX:ErrorFile=logs/hs_err_pid%p.log -XX:+PrintGCDetails -XX:+PrintGCDateStamps -XX:+PrintTenuringDistribution -XX:+PrintGCApplicationStoppedTime -Xloggc:logs/gc.log -XX:+UseGCLogFileRotation -XX:NumberOfGCLogFiles=32 -XX:GCLogFileSize=64m -Des.path.home=/home/wkq/software/elasticsearch-6.6.2 -Des.path.conf=/home/wkq/software/elasticsearch-6.6.2/config -Des.distribution.flavor=default -Des.distribution.type=tar[wkq@VM_77_25_centos ~]$
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(2.1.6) jps -V
禁止输出类名，JAR 全限定名和传递给 main 方法的参数的输出，从而产生仅本地 JVM 标识符的列表。
[wkq@VM_77_25_centos ~]$ jps -V15204 Jps13050 Elasticsearch[wkq@VM_77_25_centos ~]$
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(2.2) 常用 jps 命令
(2.2.1) jps -lm
显示 pid、全限定名、传递给 main 方法的参数
[wkq@VM_77_25_centos ~]$ jps -lm17539 sun.tools.jps.Jps -lm13050 org.elasticsearch.bootstrap.Elasticsearch -d[wkq@VM_77_25_centos ~]$[wkq@VM_77_25_centos ~]$
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(2.2.2) jps -lvm
显示 pid、全限定名、传递给 main 方法的参数、传递给 JVM 的参数
[wkq@VM_77_25_centos ~]$ jps -lvm13050 org.elasticsearch.bootstrap.Elasticsearch -d -Xms1g -Xmx1g -XX:+UseConcMarkSweepGC -XX:CMSInitiatingOccupancyFraction=75 -XX:+UseCMSInitiatingOccupancyOnly -Des.networkaddress.cache.ttl=60 -Des.networkaddress.cache.negative.ttl=10 -XX:+AlwaysPreTouch -Xss1m -Djava.awt.headless=true -Dfile.encoding=UTF-8 -Djna.nosys=true -XX:-OmitStackTraceInFastThrow -Dio.netty.noUnsafe=true -Dio.netty.noKeySetOptimization=true -Dio.netty.recycler.maxCapacityPerThread=0 -Dlog4j.shutdownHookEnabled=false -Dlog4j2.disable.jmx=true -Djava.io.tmpdir=/tmp/elasticsearch-5035355569386013893 -XX:+HeapDumpOnOutOfMemoryError -XX:HeapDumpPath=data -XX:ErrorFile=logs/hs_err_pid%p.log -XX:+PrintGCDetails -XX:+PrintGCDateStamps -XX:+PrintTenuringDistribution -XX:+PrintGCApplicationStoppedTime -Xloggc:logs/gc.log -XX:+UseGCLogFileRotation -XX:NumberOfGCLogFiles=32 -XX:GCLogFileSize=64m -Des.path.home=/home/wkq/software/elasticsearch-6.6.2 -Des.path.conf=/home/wkq/software/elasticsearch-6.6.2/config -Des.distribution.flavor=default -Des.distribution.type=tar17567 sun.tools.jps.Jps -lvm -Denv.class.path=.:/home/wkq/software/jdk1.8.0_172/lib/dt.jar:/home/wkq/software/jdk1.8.0_172/lib/tools.jar -Dapplication.home=/home/wkq/software/jdk1.8.0_172 -Xms8m[wkq@VM_77_25_centos ~]$
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(3) 虚拟机统计信息监视工具 jstat (JVM Statics Monitoring Tool)
jstat 是用于监视虚拟机各种运行状态信息的命令行工具。
(3.1) jstat 命令
语法格式
jstat [ generalOption | outputOptions vmid [ interval[s|ms] [ count ] ]
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详细信息见 man jstat
(3.1.1) jstat 命令
[wkq@VM_77_25_centos ~]$ jstat -helpUsage: jstat -help|-options jstat -<option> [-t] [-h<lines>] <vmid> [<interval> [<count>]]
Definitions: <option> An option reported by the -options option <vmid> Virtual Machine Identifier. A vmid takes the following form: <lvmid>[@<hostname>[:<port>]] Where <lvmid> is the local vm identifier for the target Java virtual machine, typically a process id; <hostname> is the name of the host running the target Java virtual machine; and <port> is the port number for the rmiregistry on the target host. See the jvmstat documentation for a more complete description of the Virtual Machine Identifier. <lines> Number of samples between header lines. <interval> Sampling interval. The following forms are allowed: <n>["ms"|"s"] Where <n> is an integer and the suffix specifies the units as milliseconds("ms") or seconds("s"). The default units are "ms". <count> Number of samples to take before terminating. -J<flag> Pass <flag> directly to the runtime system.[wkq@VM_77_25_centos ~]$
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[wkq@VM_77_25_centos ~]$ jstat -options-class-compiler-gc-gccapacity-gccause-gcmetacapacity-gcnew-gcnewcapacity-gcold-gcoldcapacity-gcutil-printcompilation[wkq@VM_77_25_centos ~]$
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(3.1.1) jstat -class 13050
[wkq@VM_77_25_centos ~]$ jstat -class 13050Loaded Bytes Unloaded Bytes Time 15177 27005.8 41 49.7 24.44[wkq@VM_77_25_centos ~]$
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(3.1.2) jstat -compiler 13050
[wkq@VM_77_25_centos ~]$ jstat -compiler 13050Compiled Failed Invalid Time FailedType FailedMethod 7469 0 0 43.18 0[wkq@VM_77_25_centos ~]$
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(3.1.3) jstat -gc 13050
[wkq@VM_77_25_centos ~]$ jstat -gc 13050 S0C S1C S0U S1U EC EU OC OU MC MU CCSC CCSU YGC YGCT FGC FGCT GCT8512.0 8512.0 0.0 24.5 68160.0 6380.0 963392.0 61694.4 77732.0 71385.7 11984.0 9862.8 69 2.112 6 0.286 2.397[wkq@VM_77_25_centos ~]$
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| 参数 | 描述 | 原文 |
|------|---------------------------------------|--------------------------------------------------------|
| S0C | 年轻代中第一个 survivor 的容量 \(kB\) | Current survivor space 0 capacity \(kB\)\. |
| S1C | 年轻代中第二个 survivor 的容量 \(kB\) | Current survivor space 1 capacity \(kB\)\. |
| S0U | 年轻代中第一个 survivor 已使用空间 \(kB\) | Survivor space 0 utilization \(kB\)\. |
| S1U | 年轻代中第二个 survivor 已使用空间 \(kB\) | Survivor space 1 utilization \(kB\)\. |
| EC | 年轻代中 Eden space 的容量 \(kB\) | Current eden space capacity \(kB\)\. |
| EU | 年轻代中 Eden space 目前已使用空间 \(kB\) | Eden space utilization \(kB\)\. |
| OC | Old space 的容量 \(kB\) | Current old space capacity \(kB\)\. |
| OU | Old space 已使用空间 \(kB\) | Old space utilization \(kB\)\. |
| MC | Metaspace 的容量 \(kB\) | Metaspace capacity \(kB\)\. |
| MU | Metaspace 已使用空间 \(kB\) | Metacspace utilization \(kB\)\. |
| CCSC | Compressed class spcage 容量 \(kB\) | Compressed class space capacity \(kB\)\. |
| CCSU | Compressed class spcage 已使用空间 \(kB\) | Compressed class space used \(kB\)\. |
| YGC | 从应用程序启动到采样时年轻代中 gc 次数 | Number of young generation garbage collection events\. |
| YGCT | 从应用程序启动到采样时年轻代中 gc 所用时间 \(s\) | Young generation garbage collection time\. |
| FGC | 从应用程序启动到采样时 old 代 \(全 gc\) gc 次数 | Number of full GC events\. |
| FGCT | 从应用程序启动到采样时 old 代 \(全 gc\) gc 所用时间 \(s\) | Full garbage collection time\. |
| GCT | 从应用程序启动到采样时 gc 用的总时间 \(s\) | Total garbage collection time\. |
(3.1.4) jstat -gccapacity 13050
[wkq@VM_77_25_centos ~]$ jstat -gccapacity 13050 NGCMN NGCMX NGC S0C S1C EC OGCMN OGCMX OGC OC MCMN MCMX MC CCSMN CCSMX CCSC YGC FGC 85184.0 85184.0 85184.0 8512.0 8512.0 68160.0 963392.0 963392.0 963392.0 963392.0 0.0 1116160.0 77732.0 0.0 1048576.0 11984.0 69 6[wkq@VM_77_25_centos ~]$
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(3.1.5) jstat -gccause 13050
[wkq@VM_77_25_centos ~]$ jstat -gccause 13050 S0 S1 E O M CCS YGC YGCT FGC FGCT GCT LGCC GCC 0.00 0.29 11.90 6.40 91.84 82.30 69 2.112 6 0.286 2.397 Allocation Failure No GC[wkq@VM_77_25_centos ~]$
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(3.1.6) jstat -gcmetacapacity 13050
[wkq@VM_77_25_centos ~]$ jstat -gcmetacapacity 13050 MCMN MCMX MC CCSMN CCSMX CCSC YGC FGC FGCT GCT 0.0 1116160.0 77732.0 0.0 1048576.0 11984.0 69 6 0.286 2.397[wkq@VM_77_25_centos ~]$
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(3.1.7) jstat -gcnew 13050
[wkq@VM_77_25_centos ~]$ jstat -gcnew 13050 S0C S1C S0U S1U TT MTT DSS EC EU YGC YGCT8512.0 8512.0 0.0 24.5 6 6 4256.0 68160.0 13229.3 69 2.112[wkq@VM_77_25_centos ~]$
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(3.1.8) jstat -gcnewcapacity 13050
[wkq@VM_77_25_centos ~]$ jstat -gcnewcapacity 13050 NGCMN NGCMX NGC S0CMX S0C S1CMX S1C ECMX EC YGC FGC 85184.0 85184.0 85184.0 8512.0 8512.0 8512.0 8512.0 68160.0 68160.0 69 6[wkq@VM_77_25_centos ~]$
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(3.1.9) jstat -gcold 13050
[wkq@VM_77_25_centos ~]$ jstat -gcold 13050 MC MU CCSC CCSU OC OU YGC FGC FGCT GCT 77732.0 71385.7 11984.0 9862.8 963392.0 61694.4 69 6 0.286 2.397
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(3.1.10) jstat -gcoldcapacity 13050
[wkq@VM_77_25_centos ~]$ jstat -gcoldcapacity 13050 OGCMN OGCMX OGC OC YGC FGC FGCT GCT 963392.0 963392.0 963392.0 963392.0 69 6 0.286 2.397[wkq@VM_77_25_centos ~]$
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(3.1.11) jstat -gcutil 13050
垃圾回收状态摘要
[wkq@VM_77_25_centos ~]$ jstat -gcutil 13050 S0 S1 E O M CCS YGC YGCT FGC FGCT GCT 0.00 0.29 24.37 6.40 91.84 82.30 69 2.112 6 0.286 2.397[wkq@VM_77_25_centos ~]$
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| 参数 | 描述 | 原文 |
|------|-----------------------------------|--------------------------------------------------------------------------------|
| S0 | 年轻代中第一个 survivor 已使用的占当前容量百分比 | Survivor space 0 utilization as a percentage of the space's current capacity\. |
| S1 | 年轻代中第二个 survivor 已使用的占当前容量百分比 | Survivor space 1 utilization as a percentage of the space's current capacity\. |
| E | Eden space 中 Eden 已使用的占当前容量百分比 | Eden space utilization as a percentage of the space's current capacity\. |
| O | Old space 已使用的占当前容量百分比 | Old space utilization as a percentage of the space's current capacity\. |
| M | Metaspace 已使用的占当前容量百分比 | Metaspace utilization as a percentage of the space's current capacity\. |
| CCS | Compressed class 空间利用率 | Compressed class space utilization as a percentage\. |
| YGC | 从应用程序启动到采样时 young generation gc 次数 | Number of young generation GC events\. |
| YGCT | 从应用程序启动到采样时 Young gc 所用时间\(s\) | Young generation garbage collection time\. |
| FGC | 从应用程序启动到采样时 Full gc 次数 | Number of full GC events\. |
| FGCT | 从应用程序启动到采样时 Full gc 所用时间\(s\) | Full garbage collection time\. |
| GCT | 从应用程序启动到采样时 gc 用的总时间\(s\) | Total garbage collection time\. |
(3.1.12) jstat -printcompilation 13050
[wkq@VM_77_25_centos ~]$ jstat -printcompilation 13050Compiled Size Type Method 7469 63 1 org/apache/logging/log4j/spi/AbstractLogger trace[wkq@VM_77_25_centos ~]$
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(3.2) 常用 jstat 命令
(3.2.1) jstat -gc -h5 -t 13050 1000 10
分析进程 id 为 13050 的 gc 情况，每隔 1000ms 打印一次记录，打印 10 次停止，每 5 行后打印指标头部
-gc 查看 gc 情况
-h5 每 5 行后打印指标头部
-t 进程启动时间
13050 进程 id 也就是 linux 的 pid
1000 每隔 1000ms 打印一次
10 共打印 10 行
[wkq@VM_77_25_centos ~]$ jstat -gc -h5 -t 13050 1000 10Timestamp S0C S1C S0U S1U EC EU OC OU MC MU CCSC CCSU YGC YGCT FGC FGCT GCT 217492.5 8512.0 8512.0 0.0 77.3 68160.0 13154.8 963392.0 60728.2 77732.0 71386.5 11984.0 9862.9 133 2.921 8 0.947 3.868 217493.7 8512.0 8512.0 0.0 77.3 68160.0 13154.8 963392.0 60728.2 77732.0 71386.5 11984.0 9862.9 133 2.921 8 0.947 3.868 217494.7 8512.0 8512.0 0.0 77.3 68160.0 14055.9 963392.0 60728.2 77732.0 71386.5 11984.0 9862.9 133 2.921 8 0.947 3.868 217495.7 8512.0 8512.0 0.0 77.3 68160.0 14055.9 963392.0 60728.2 77732.0 71386.5 11984.0 9862.9 133 2.921 8 0.947 3.868 217496.7 8512.0 8512.0 0.0 77.3 68160.0 14055.9 963392.0 60728.2 77732.0 71386.5 11984.0 9862.9 133 2.921 8 0.947 3.868Timestamp S0C S1C S0U S1U EC EU OC OU MC MU CCSC CCSU YGC YGCT FGC FGCT GCT 217497.7 8512.0 8512.0 0.0 77.3 68160.0 14055.9 963392.0 60728.2 77732.0 71386.5 11984.0 9862.9 133 2.921 8 0.947 3.868 217498.7 8512.0 8512.0 0.0 77.3 68160.0 14055.9 963392.0 60728.2 77732.0 71386.5 11984.0 9862.9 133 2.921 8 0.947 3.868 217499.7 8512.0 8512.0 0.0 77.3 68160.0 14055.9 963392.0 60728.2 77732.0 71386.5 11984.0 9862.9 133 2.921 8 0.947 3.868 217500.7 8512.0 8512.0 0.0 77.3 68160.0 14055.9 963392.0 60728.2 77732.0 71386.5 11984.0 9862.9 133 2.921 8 0.947 3.868 217501.7 8512.0 8512.0 0.0 77.3 68160.0 14068.0 963392.0 60728.2 77732.0 71386.5 11984.0 9862.9 133 2.921 8 0.947 3.868[wkq@VM_77_25_centos ~]$
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我们可以比较 Java 进程的启动时间以及总 GC 时间（GCT 列），或者两次测量的间隔时间以及总 GC 时间的增量，来得出 GC 时间占运行时间的比例。如果该比例超过 20%，则说明目前堆的压力较大；如果该比例超过 90%，则说明堆里几乎没有可用空间，随时都可能抛出 OOM 异常。
(3.2.2) jstat -gcutil -h5 -t 13050 1000 10
分析进程 id 为 13050 的 gcutil 情况，每隔 1000ms 打印一次记录，打印 15 次停止，每 5 行后打印指标头部
-gcutil 查看 gcutil 情况
-h5 每 5 行后打印指标头部
-t 进程启动时间
13050 进程 id 也就是 linux 的 pid
1000 每隔 1000ms 打印一次
10 共打印 10 行
[wkq@VM_77_25_centos ~]$ jstat -gcutil -h5 -t 13050 1000 10Timestamp S0 S1 E O M CCS YGC YGCT FGC FGCT GCT 217569.9 0.00 0.91 23.55 6.30 91.84 82.30 133 2.921 8 0.947 3.868 217570.9 0.00 0.91 23.55 6.30 91.84 82.30 133 2.921 8 0.947 3.868 217571.9 0.00 0.91 23.55 6.30 91.84 82.30 133 2.921 8 0.947 3.868 217572.9 0.00 0.91 23.55 6.30 91.84 82.30 133 2.921 8 0.947 3.868 217573.9 0.00 0.91 23.55 6.30 91.84 82.30 133 2.921 8 0.947 3.868Timestamp S0 S1 E O M CCS YGC YGCT FGC FGCT GCT 217574.9 0.00 0.91 23.55 6.30 91.84 82.30 133 2.921 8 0.947 3.868 217575.9 0.00 0.91 23.55 6.30 91.84 82.30 133 2.921 8 0.947 3.868 217576.9 0.00 0.91 23.55 6.30 91.84 82.30 133 2.921 8 0.947 3.868 217577.9 0.00 0.91 23.55 6.30 91.84 82.30 133 2.921 8 0.947 3.868 217578.9 0.00 0.91 23.55 6.30 91.84 82.30 133 2.921 8 0.947 3.868[wkq@VM_77_25_centos ~]$
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(4) Java 配置信息工具 jinfo (Java Configuration Info )
jinfo 是实时查看和调整虚拟机各项参数的工具
(4.1) jinfo 命令
语法格式
[wkq@VM_77_25_centos ~]$ jinfo -helpUsage: jinfo [option] <pid> (to connect to running process) jinfo [option] <executable <core> (to connect to a core file) jinfo [option] [server_id@]<remote server IP or hostname> (to connect to remote debug server)
where <option> is one of: -flag <name> to print the value of the named VM flag -flag [+|-]<name> to enable or disable the named VM flag -flag <name>=<value> to set the named VM flag to the given value -flags to print VM flags -sysprops to print Java system properties <no option> to print both of the above -h | -help to print this help message[wkq@VM_77_25_centos ~]$
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[wkq@VM_77_25_centos ~]$ jinfo -optionUsage: jinfo [option] <pid> (to connect to running process) jinfo [option] <executable <core> (to connect to a core file) jinfo [option] [server_id@]<remote server IP or hostname> (to connect to remote debug server)
where <option> is one of: -flag <name> to print the value of the named VM flag -flag [+|-]<name> to enable or disable the named VM flag -flag <name>=<value> to set the named VM flag to the given value -flags to print VM flags -sysprops to print Java system properties <no option> to print both of the above -h | -help to print this help message[wkq@VM_77_25_centos ~]$
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如果遇到 Error attaching to process: sun.jvm.hotspot.debugger.DebuggerException: Can't attach to the process: ptrace(PTRACE_ATTACH, ..) failed for : Operation not permitted，执行 echo 0 | sudo tee /proc/sys/kernel/yama/ptrace_scope 命令即可
(4.1.1) jinfo pid
[wkq@VM_77_25_centos ~]$ jinfo 13050Attaching to process ID 13050, please wait...Debugger attached successfully.Server compiler detected.JVM version is 25.172-b11Java System Properties:
jna.platform.library.path = /usr/lib64:/lib64:/usr/lib:/lib:/usr/lib64/dyninst:/usr/lib64/mysqljava.runtime.name = Java(TM) SE Runtime Environmentsun.boot.library.path = /home/wkq/software/jdk1.8.0_172/jre/lib/amd64java.vm.version = 25.172-b11es.path.home = /home/wkq/software/elasticsearch-6.6.2log4j.shutdownHookEnabled = falsejava.vendor.url = http://java.oracle.com/java.vm.vendor = Oracle Corporationpath.separator = :file.encoding.pkg = sun.iojava.vm.name = Java HotSpot(TM) 64-Bit Server VMjna.loaded = truesun.os.patch.level = unknownuser.country = USsun.java.launcher = SUN_STANDARDes.networkaddress.cache.negative.ttl = 10jna.nosys = truejava.vm.specification.name = Java Virtual Machine Specificationuser.dir = /home/wkq/software/elasticsearch-6.6.2java.runtime.version = 1.8.0_172-b11java.awt.graphicsenv = sun.awt.X11GraphicsEnvironmentjava.endorsed.dirs = /home/wkq/software/jdk1.8.0_172/jre/lib/endorsedos.arch = amd64java.io.tmpdir = /tmp/elasticsearch-5035355569386013893line.separator =
es.networkaddress.cache.ttl = 60es.logs.node_name = elasticsearch_001_datajava.vm.specification.vendor = Oracle Corporationos.name = Linuxio.netty.noKeySetOptimization = truesun.jnu.encoding = ANSI_X3.4-1968jnidispatch.path = /tmp/elasticsearch-5035355569386013893/jna-117789/jna8829728915470247279.tmpjava.library.path = /usr/java/packages/lib/amd64:/usr/lib64:/lib64:/lib:/usr/libsun.nio.ch.bugLevel =es.logs.cluster_name = elasticsearch_testjava.specification.name = Java Platform API Specificationjava.class.version = 52.0sun.management.compiler = HotSpot 64-Bit Tiered Compilersos.version = 3.10.0-957.21.3.el7.x86_64user.home = /home/wkquser.timezone = Asia/Shanghaijava.awt.printerjob = sun.print.PSPrinterJobfile.encoding = UTF-8java.specification.version = 1.8es.distribution.type = tario.netty.recycler.maxCapacityPerThread = 0user.name = wkqes.logs.base_path = /home/wkq/software/elasticsearch-6.6.2/logsjava.class.path = es.path.conf = /home/wkq/software/elasticsearch-6.6.2/configjava.vm.specification.version = 1.8java.home = /home/wkq/software/jdk1.8.0_172/jresun.java.command = org.elasticsearch.bootstrap.Elasticsearch -dsun.arch.data.model = 64io.netty.noUnsafe = trueuser.language = enjava.specification.vendor = Oracle Corporationawt.toolkit = sun.awt.X11.XToolkitjava.vm.info = mixed modejava.version = 1.8.0_172java.ext.dirs = /home/wkq/software/jdk1.8.0_172/jre/lib/ext:/usr/java/packages/lib/extsun.boot.class.path = java.awt.headless = truejava.vendor = Oracle Corporationfile.separator = /java.vendor.url.bug = http://bugreport.sun.com/bugreport/es.distribution.flavor = defaultsun.io.unicode.encoding = UnicodeLittlesun.cpu.endian = littlelog4j2.disable.jmx = truesun.cpu.isalist =
VM Flags:Non-default VM flags: -XX:+AlwaysPreTouch -XX:CICompilerCount=2 -XX:CMSInitiatingOccupancyFraction=75 -XX:ErrorFile=null -XX:GCLogFileSize=67108864 -XX:+HeapDumpOnOutOfMemoryError -XX:HeapDumpPath=null -XX:InitialHeapSize=1073741824 -XX:MaxHeapSize=1073741824 -XX:MaxNewSize=87228416 -XX:MaxTenuringThreshold=6 -XX:MinHeapDeltaBytes=196608 -XX:NewSize=87228416 -XX:NumberOfGCLogFiles=32 -XX:OldPLABSize=16 -XX:OldSize=986513408 -XX:-OmitStackTraceInFastThrow -XX:+PrintGC -XX:+PrintGCApplicationStoppedTime -XX:+PrintGCDateStamps -XX:+PrintGCDetails -XX:+PrintGCTimeStamps -XX:+PrintTenuringDistribution -XX:ThreadStackSize=1024 -XX:+UseCMSInitiatingOccupancyOnly -XX:+UseCompressedClassPointers -XX:+UseCompressedOops -XX:+UseConcMarkSweepGC -XX:+UseGCLogFileRotation -XX:+UseParNewGCCommand line: -Xms1g -Xmx1g -XX:+UseConcMarkSweepGC -XX:CMSInitiatingOccupancyFraction=75 -XX:+UseCMSInitiatingOccupancyOnly -Des.networkaddress.cache.ttl=60 -Des.networkaddress.cache.negative.ttl=10 -XX:+AlwaysPreTouch -Xss1m -Djava.awt.headless=true -Dfile.encoding=UTF-8 -Djna.nosys=true -XX:-OmitStackTraceInFastThrow -Dio.netty.noUnsafe=true -Dio.netty.noKeySetOptimization=true -Dio.netty.recycler.maxCapacityPerThread=0 -Dlog4j.shutdownHookEnabled=false -Dlog4j2.disable.jmx=true -Djava.io.tmpdir=/tmp/elasticsearch-5035355569386013893 -XX:+HeapDumpOnOutOfMemoryError -XX:HeapDumpPath=data -XX:ErrorFile=logs/hs_err_pid%p.log -XX:+PrintGCDetails -XX:+PrintGCDateStamps -XX:+PrintTenuringDistribution -XX:+PrintGCApplicationStoppedTime -Xloggc:logs/gc.log -XX:+UseGCLogFileRotation -XX:NumberOfGCLogFiles=32 -XX:GCLogFileSize=64m -Des.path.home=/home/wkq/software/elasticsearch-6.6.2 -Des.path.conf=/home/wkq/software/elasticsearch-6.6.2/config -Des.distribution.flavor=default -Des.distribution.type=tar
[wkq@VM_77_25_centos ~]$
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(4.1.2) jinfo -flag MaxMetaspaceSize pid
[wkq@VM_77_25_centos ~]$ jinfo -flag MaxMetaspaceSize 13050-XX:MaxMetaspaceSize=18446744073709547520[wkq@VM_77_25_centos ~]$
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(4.1.3) jinfo -flag ThreadStackSize pid
[wkq@VM_77_25_centos ~]$ jinfo -flag ThreadStackSize 13050-XX:ThreadStackSize=1024[wkq@VM_77_25_centos ~]$
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(4.1.4) jinfo -flag MaxNewSize pid
[wkq@VM_77_25_centos ~]$ jinfo -flag MaxNewSize 13050-XX:MaxNewSize=87228416[wkq@VM_77_25_centos ~]$
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(4.1.5) jinfo -flag CMSInitiatingOccupancyFraction pid
[wkq@VM_77_25_centos ~]$ jinfo -flag CMSInitiatingOccupancyFraction 13050-XX:CMSInitiatingOccupancyFraction=75[wkq@VM_77_25_centos ~]$
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(4.1.6) 查看所有 JVM 参数 java -XX:+PrintFlagsInitial
[wkq@VM_77_25_centos ~]$ java -XX:+PrintFlagsInitial[Global flags] uintx AdaptiveSizeDecrementScaleFactor = 4 {product} uintx AdaptiveSizeMajorGCDecayTimeScale = 10 {product}
...
intx WorkAroundNPTLTimedWaitHang = 1 {product} uintx YoungGenerationSizeIncrement = 20 {product} uintx YoungGenerationSizeSupplement = 80 {product} uintx YoungGenerationSizeSupplementDecay = 8 {product} uintx YoungPLABSize = 4096 {product} bool ZeroTLAB = false {product} intx hashCode = 5 {product}[wkq@VM_77_25_centos ~]$
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(4.1.7) 查看所有支持动态修改的 JVM 参数 java -XX:+PrintFlagsInitial | grep manageable
[wkq@VM_77_25_centos ~]$ java -XX:+PrintFlagsInitial | grep manageable intx CMSAbortablePrecleanWaitMillis = 100 {manageable} intx CMSTriggerInterval = -1 {manageable} intx CMSWaitDuration = 2000 {manageable} bool HeapDumpAfterFullGC = false {manageable} bool HeapDumpBeforeFullGC = false {manageable} bool HeapDumpOnOutOfMemoryError = false {manageable} ccstr HeapDumpPath = {manageable} uintx MaxHeapFreeRatio = 70 {manageable} uintx MinHeapFreeRatio = 40 {manageable} bool PrintClassHistogram = false {manageable} bool PrintClassHistogramAfterFullGC = false {manageable} bool PrintClassHistogramBeforeFullGC = false {manageable} bool PrintConcurrentLocks = false {manageable} bool PrintGC = false {manageable} bool PrintGCDateStamps = false {manageable} bool PrintGCDetails = false {manageable} bool PrintGCID = false {manageable} bool PrintGCTimeStamps = false {manageable}[wkq@VM_77_25_centos ~]$
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(4.1.7) 调整 JVM 参数-布尔类型
jinfo -flag [+|-]<name> PID
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[wkq@VM_77_25_centos ~]$ jinfo -flag +PrintGC 13050[wkq@VM_77_25_centos ~]$[wkq@VM_77_25_centos ~]$ jinfo -flag +PrintGCDetails 13050[wkq@VM_77_25_centos ~]$
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如果没报错则代表生效，加完以后可以通过 jinfo -flags 13050 验证
(4.1.8) 调整 JVM 参数-数字/字符串类型
jinfo -flag <name>=<value> PID
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[wkq@VM_77_25_centos ~]$ jinfo -flag MaxHeapFreeRatio=65 13050[wkq@VM_77_25_centos ~]$
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没报错相当于修改成功，但是怎么验证是否生效，可以通过 jinfo -flags 13050 验证
[wkq@VM_77_25_centos ~]$ jinfo -flags 13050Attaching to process ID 13050, please wait...Debugger attached successfully.Server compiler detected.JVM version is 25.172-b11Non-default VM flags: -XX:+AlwaysPreTouch -XX:CICompilerCount=2 -XX:CMSInitiatingOccupancyFraction=75 -XX:ErrorFile=null -XX:GCLogFileSize=67108864 -XX:+HeapDumpOnOutOfMemoryError -XX:HeapDumpPath=null -XX:InitialHeapSize=1073741824 -XX:MaxHeapFreeRatio=65 -XX:MaxHeapSize=1073741824 -XX:MaxNewSize=87228416 -XX:MaxTenuringThreshold=6 -XX:MinHeapDeltaBytes=196608 -XX:NewSize=87228416 -XX:NumberOfGCLogFiles=32 -XX:OldPLABSize=16 -XX:OldSize=986513408 -XX:-OmitStackTraceInFastThrow -XX:+PrintGC -XX:+PrintGCApplicationStoppedTime -XX:+PrintGCDateStamps -XX:+PrintGCDetails -XX:+PrintGCTimeStamps -XX:+PrintTenuringDistribution -XX:ThreadStackSize=1024 -XX:+UseCMSInitiatingOccupancyOnly -XX:+UseCompressedClassPointers -XX:+UseCompressedOops -XX:+UseConcMarkSweepGC -XX:+UseGCLogFileRotation -XX:+UseParNewGCCommand line: -Xms1g -Xmx1g -XX:+UseConcMarkSweepGC -XX:CMSInitiatingOccupancyFraction=75 -XX:+UseCMSInitiatingOccupancyOnly -Des.networkaddress.cache.ttl=60 -Des.networkaddress.cache.negative.ttl=10 -XX:+AlwaysPreTouch -Xss1m -Djava.awt.headless=true -Dfile.encoding=UTF-8 -Djna.nosys=true -XX:-OmitStackTraceInFastThrow -Dio.netty.noUnsafe=true -Dio.netty.noKeySetOptimization=true -Dio.netty.recycler.maxCapacityPerThread=0 -Dlog4j.shutdownHookEnabled=false -Dlog4j2.disable.jmx=true -Djava.io.tmpdir=/tmp/elasticsearch-5035355569386013893 -XX:+HeapDumpOnOutOfMemoryError -XX:HeapDumpPath=data -XX:ErrorFile=logs/hs_err_pid%p.log -XX:+PrintGCDetails -XX:+PrintGCDateStamps -XX:+PrintTenuringDistribution -XX:+PrintGCApplicationStoppedTime -Xloggc:logs/gc.log -XX:+UseGCLogFileRotation -XX:NumberOfGCLogFiles=32 -XX:GCLogFileSize=64m -Des.path.home=/home/wkq/software/elasticsearch-6.6.2 -Des.path.conf=/home/wkq/software/elasticsearch-6.6.2/config -Des.distribution.flavor=default -Des.distribution.type=tar[wkq@VM_77_25_centos ~]$
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通过 jinfo -flags 13050 获取的结果可以看到
出现 Command failed in target VM 则表示这个 flag 参数不支持
[wkq@VM_77_25_centos ~]$ jinfo -flag ErrorFile=/home/wkq/es_error_file 13050Exception in thread "main" com.sun.tools.attach.AttachOperationFailedException: flag 'ErrorFile' cannot be changed
at sun.tools.attach.LinuxVirtualMachine.execute(LinuxVirtualMachine.java:229) at sun.tools.attach.HotSpotVirtualMachine.executeCommand(HotSpotVirtualMachine.java:261) at sun.tools.attach.HotSpotVirtualMachine.setFlag(HotSpotVirtualMachine.java:234) at sun.tools.jinfo.JInfo.flag(JInfo.java:134) at sun.tools.jinfo.JInfo.main(JInfo.java:81)[wkq@VM_77_25_centos ~]$
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<br>
<br>
(5) Java 内存映像工具 jmap
Jmap 是一个可以输出所有内存中对象的工具，甚至可以将 VM 中的 heap，以二进制输出成文本。打印出某个 java 进程（使用 pid）内存内的，所有‘对象’的情况（如：产生那些对象，及其数量）。
(5.1) jmap 命令
[wkq@VM_77_25_centos ~]$ jmap -helpUsage: jmap [option] <pid> (to connect to running process) jmap [option] <executable <core> (to connect to a core file) jmap [option] [server_id@]<remote server IP or hostname> (to connect to remote debug server)
where <option> is one of: <none> to print same info as Solaris pmap -heap to print java heap summary -histo[:live] to print histogram of java object heap; if the "live" suboption is specified, only count live objects -clstats to print class loader statistics -finalizerinfo to print information on objects awaiting finalization -dump:<dump-options> to dump java heap in hprof binary format dump-options: live dump only live objects; if not specified, all objects in the heap are dumped. format=b binary format file=<file> dump heap to <file> Example: jmap -dump:live,format=b,file=heap.bin <pid> -F force. Use with -dump:<dump-options> <pid> or -histo to force a heap dump or histogram when <pid> does not respond. The "live" suboption is not supported in this mode. -h | -help to print this help message -J<flag> to pass <flag> directly to the runtime system[wkq@VM_77_25_centos ~]$
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[wkq@VM_77_25_centos ~]$ jmap -optionsUsage: jmap [option] <pid> (to connect to running process) jmap [option] <executable <core> (to connect to a core file) jmap [option] [server_id@]<remote server IP or hostname> (to connect to remote debug server)
where <option> is one of: <none> to print same info as Solaris pmap -heap to print java heap summary -histo[:live] to print histogram of java object heap; if the "live" suboption is specified, only count live objects -clstats to print class loader statistics -finalizerinfo to print information on objects awaiting finalization -dump:<dump-options> to dump java heap in hprof binary format dump-options: live dump only live objects; if not specified, all objects in the heap are dumped. format=b binary format file=<file> dump heap to <file> Example: jmap -dump:live,format=b,file=heap.bin <pid> -F force. Use with -dump:<dump-options> <pid> or -histo to force a heap dump or histogram when <pid> does not respond. The "live" suboption is not supported in this mode. -h | -help to print this help message -J<flag> to pass <flag> directly to the runtime system[wkq@VM_77_25_centos ~]$
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更多详细信息参考 man jmap
(5.1.1) jmap pid
[wkq@VM_77_25_centos ~]$ jmap 13050Attaching to process ID 13050, please wait...Debugger attached successfully.Server compiler detected.JVM version is 25.172-b110x0000000000400000 7K /home/wkq/software/jdk1.8.0_172/bin/java0x00007fb911271000 49K /home/wkq/software/jdk1.8.0_172/jre/lib/amd64/libmanagement.so0x00007fb91167a000 86K /usr/lib64/libgcc_s-4.8.5-20150702.so.10x00007fb911890000 251K /home/wkq/software/jdk1.8.0_172/jre/lib/amd64/libsunec.so0x00007fb9242c2000 112K /home/wkq/software/jdk1.8.0_172/jre/lib/amd64/libnet.so0x00007fb9244d9000 91K /home/wkq/software/jdk1.8.0_172/jre/lib/amd64/libnio.so0x00007fb94065d000 125K /home/wkq/software/jdk1.8.0_172/jre/lib/amd64/libzip.so0x00007fb940879000 60K /usr/lib64/libnss_files-2.17.so0x00007fb940a8c000 221K /home/wkq/software/jdk1.8.0_172/jre/lib/amd64/libjava.so0x00007fb940cb8000 64K /home/wkq/software/jdk1.8.0_172/jre/lib/amd64/libverify.so0x00007fb940ec7000 43K /usr/lib64/librt-2.17.so0x00007fb9410cf000 1115K /usr/lib64/libm-2.17.so0x00007fb9413d1000 16667K /home/wkq/software/jdk1.8.0_172/jre/lib/amd64/server/libjvm.so0x00007fb9423d2000 2068K /usr/lib64/libc-2.17.so0x00007fb942793000 19K /usr/lib64/libdl-2.17.so0x00007fb942997000 101K /home/wkq/software/jdk1.8.0_172/lib/amd64/jli/libjli.so0x00007fb942bad000 140K /usr/lib64/libpthread-2.17.so0x00007fb942dc9000 155K /usr/lib64/ld-2.17.so[wkq@VM_77_25_centos ~]$
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(5.1.2) jmap -dump:[live,] format=b, file=file_path
[wkq@VM_77_25_centos ~]$ jmap -dump:live,format=b,file=13050.log 13050Dumping heap to /home/wkq/13050.log ...Heap dump file created[wkq@VM_77_25_centos ~]$
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(5.1.3) jmap -finalizerinfo pid
[wkq@VM_77_25_centos ~]$ jmap -finalizerinfo 13050Attaching to process ID 13050, please wait...Debugger attached successfully.Server compiler detected.JVM version is 25.172-b11Number of objects pending for finalization: 0[wkq@VM_77_25_centos ~]$
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(5.1.4) jmap -heap pid
jmap -heap pid
jmap-J-d64 -heap pid
[wkq@VM_77_25_centos ~]$ jmap -heap 13050Attaching to process ID 13050, please wait...Debugger attached successfully.Server compiler detected.JVM version is 25.172-b11
using parallel threads in the new generation.using thread-local object allocation.Concurrent Mark-Sweep GC
Heap Configuration: MinHeapFreeRatio = 40 MaxHeapFreeRatio = 70 MaxHeapSize = 1073741824 (1024.0MB) NewSize = 87228416 (83.1875MB) MaxNewSize = 87228416 (83.1875MB) OldSize = 986513408 (940.8125MB) NewRatio = 2 SurvivorRatio = 8 MetaspaceSize = 21807104 (20.796875MB) CompressedClassSpaceSize = 1073741824 (1024.0MB) MaxMetaspaceSize = 17592186044415 MB G1HeapRegionSize = 0 (0.0MB)
Heap Usage:New Generation (Eden + 1 Survivor Space): capacity = 78512128 (74.875MB) used = 7022576 (6.6972503662109375MB) free = 71489552 (68.17774963378906MB) 8.94457477958055% usedEden Space: capacity = 69795840 (66.5625MB) used = 7022576 (6.6972503662109375MB) free = 62773264 (59.86524963378906MB) 10.061596794307512% usedFrom Space: capacity = 8716288 (8.3125MB) used = 0 (0.0MB) free = 8716288 (8.3125MB) 0.0% usedTo Space: capacity = 8716288 (8.3125MB) used = 0 (0.0MB) free = 8716288 (8.3125MB) 0.0% usedconcurrent mark-sweep generation: capacity = 986513408 (940.8125MB) used = 62168384 (59.28839111328125MB) free = 924345024 (881.5241088867188MB) 6.301828591061582% used
22982 interned Strings occupying 3212304 bytes.[wkq@VM_77_25_centos ~]$
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(5.1.5) jmap -histo pid
[wkq@VM_77_25_centos ~]$ jmap -histo 13050 | more
num #instances #bytes class name---------------------------------------------- 1: 258021 20550728 [C 2: 432469 13839008 java.util.HashMap$Node 3: 228108 5474592 java.lang.String 4: 38596 4839800 [Ljava.util.HashMap$Node; 5: 86202 4137696 java.util.HashMap 6: 21464 2574920 [B 7: 74456 2382592 java.util.Collections$UnmodifiableMap 8: 12306 2118456 [I 9: 30839 1957320 [Ljava.lang.Object; 10: 15798 1730136 java.lang.Class 11: 52294 1673408 java.util.concurrent.ConcurrentHashMap$Node 12: 24594 787008 java.util.AbstractList$Itr 13: 49038 784608 org.elasticsearch.common.lucene.LoggerInfoStream$$Lambda$3048/931367447 14: 24519 784608 org.elasticsearch.index.engine.Engine$$Lambda$3100/1060530393 15: 23576 754432 java.lang.ref.WeakReference 16: 30639 735336 java.util.Arrays$ArrayList 17: 24519 588456 [Lorg.elasticsearch.common.lease.Releasable; 18: 24519 588456 org.elasticsearch.index.engine.Engine$Searcher 19: 8132 585504 java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask 20: 9564 535584 java.lang.invoke.MemberName 21: 6052 532576 java.lang.reflect.Method 22: 33099 529584 java.lang.Object
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(5.1.6) jmap -clstats pid
[wkq@VM_77_25_centos ~]$ jmap -clstats 13050Attaching to process ID 13050, please wait...Debugger attached successfully.Server compiler detected.JVM version is 25.172-b11finding class loader instances ..done.computing per loader stat ..done.please wait.. computing liveness.liveness analysis may be inaccurate ...class_loader classes bytes parent_loader alive? type
<bootstrap> 2353 4122324 null live <internal>0x00000000c5fa9378 1 714 null dead org/elasticsearch/painless/lookup/PainlessLookupBuilder$BridgeLoader@0x00000001003f45d00x00000000c5fa9878 1 714 null dead org/elasticsearch/painless/lookup/PainlessLookupBuilder$BridgeLoader@0x00000001003f45d00x00000000c58b8708 0 0 0x00000000c544a3d0 dead org/elasticsearch/plugins/ExtendedPluginsClassLoader@0x0000000100263e900x00000000c5ab86a8 1 1471 0x00000000c544a3d0 dead sun/reflect/DelegatingClassLoader@0x000000010000a0280x00000000c5ac4b28 11 20182 0x00000000c5c12600 dead java/net/FactoryURLClassLoader@0x0000000100259738
...
total = 86 11582 19740221 N/A alive=1, dead=85 N/A[wkq@VM_77_25_centos ~]$
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省略部分详细信息
<br>
<br>
(6) 虚拟机堆转储快照分析工具 jhat
<br>
<br>
(7) Java 堆栈跟踪工具 jstack (Java Stack Trace)
jstack 主要用来查看某个 Java 进程内的线程堆栈信息。
在实际运行中，往往一次 dump 的信息，还不足以确认问题。建议产生三次 dump 信息，如果每次 dump 都指向同一个问题，我们才确定问题的典型性。
(7.1) jstack 命令
```[wkq@VM7725_centos ~]$ jstack -help
Usage:
jstack [-l] <pid>
(to connect to running process)
jstack -F [-m] [-l] <pid>
(to connect to a hung process)
jstack [-m] [-l] <executable> <core>
(to connect to a core file)
jstack [-m] [-l] [server_id@]<remote server IP or hostname>
(to connect to a remote debug server)
Options:
-F to force a thread dump. Use when jstack <pid> does not respond (process is hung)
-m to print both java and native frames (mixed mode)
-l long listing. Prints additional information about locks
-h or -help to print this help message
[wkq@VM7725_centos ~]$
```log[wkq@VM_77_25_centos ~]$ jstack -optionsUsage: jstack [-l] <pid> (to connect to running process) jstack -F [-m] [-l] <pid> (to connect to a hung process) jstack [-m] [-l] <executable> <core> (to connect to a core file) jstack [-m] [-l] [server_id@]<remote server IP or hostname> (to connect to a remote debug server)
Options: -F to force a thread dump. Use when jstack <pid> does not respond (process is hung) -m to print both java and native frames (mixed mode) -l long listing. Prints additional information about locks -h or -help to print this help message[wkq@VM_77_25_centos ~]$
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(7.1.1) jstack pid
[wkq@VM_77_25_centos ~]$ jstack 130502020-03-29 08:55:30Full thread dump Java HotSpot(TM) 64-Bit Server VM (25.172-b11 mixed mode):
"Attach Listener" #48 daemon prio=9 os_prio=0 tid=0x00007fb90805b800 nid=0x1c9f waiting on condition [0x0000000000000000] java.lang.Thread.State: RUNNABLE
"elasticsearch[elasticsearch_001_data][flush][T#1]" #47 daemon prio=5 os_prio=0 tid=0x00007fb93c693800 nid=0x376c waiting on condition [0x00007fb8fd520000] java.lang.Thread.State: WAITING (parking) at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x00000000c600d388> (a org.elasticsearch.common.util.concurrent.EsExecutors$ExecutorScalingQueue)...[wkq@VM_77_25_centos ~]$
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(7.1.2) jstack -l pid
[wkq@VM_77_25_centos ~]$ jstack -l 130502020-03-29 23:09:50Full thread dump Java HotSpot(TM) 64-Bit Server VM (25.172-b11 mixed mode):
"elasticsearch[elasticsearch_001_data][generic][T#8]" #51 daemon prio=5 os_prio=0 tid=0x00007fb93df68000 nid=0x77cf waiting on condition [0x00007fb8ff934000] java.lang.Thread.State: TIMED_WAITING (parking) at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x00000000c5ed5f70> (a org.elasticsearch.common.util.concurrent.EsExecutors$ExecutorScalingQueue) at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)
Locked ownable synchronizers: - None
...
"Attach Listener" #48 daemon prio=9 os_prio=0 tid=0x00007fb90805b800 nid=0x1c9f waiting on condition [0x0000000000000000] java.lang.Thread.State: RUNNABLE
...
"VM Thread" os_prio=0 tid=0x00007fb93c0b5000 nid=0x32ff runnable
"Gang worker#0 (Parallel GC Threads)" os_prio=0 tid=0x00007fb93c01d000 nid=0x32fd runnable
"Concurrent Mark-Sweep GC Thread" os_prio=0 tid=0x00007fb93c040000 nid=0x32fe runnable
"VM Periodic Task Thread" os_prio=0 tid=0x00007fb93c103800 nid=0x3307 waiting on condition
JNI global references: 8827
[wkq@VM_77_25_centos ~]$
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(8) Java 监视与管理控制台 JConsole (Java Monitoring and Managerment Console)
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(9) 多合一故障处理工具 VisuaIVM (All-in-One Java Troubleshooting Tool)
VisuaIVM (All-in-One Java Troubleshooting Tool) 是到目前为止随 JDK 发布的功能最强大的运行监视和故障处理程序。
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References
[1] 《深入理解 JAVA 虚拟机: JVM 高级特性与最佳实践》 周志明
[2] JVM 性能调优监控工具 jps、jstack、jmap、jhat、jstat、hprof 使用详解
[3] JAVA JPS 命令详解
[4] jstat 使用详解（分析 JVM 的使用情况）
[5] 使用 Java 监控工具出现 Can't attach to the process
[6] JVM 系列：jinfo 命令详解
[7] jmap 命令详解
[8] jstack 命令详解
[9] 深入拆解 Java 虚拟机 - 30 | Java 虚拟机的监控及诊断工具（命令行篇）
[10] oracle monitoring-tools-and-commands
[11] 深入拆解 Java 虚拟机 - 31 | Java 虚拟机的监控及诊断工具（GUI 篇）
[12] visualvm
[13] jitwatch
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