一文讲解JDK自带监控工具查看 JVM 情况

news2024/11/15 17:38:19

在一文带你了解阿里的开源Java诊断工具：Arthas_出世&入世的博客-CSDN博客这篇文章中介绍了Arthas的强大功能，但是有些生成环境没有安装，所以还是需要会使用JDK 自带监控JVM的工具。

常用的JDK 自带监控工具如下：

jps：得到 Java 进程列表

jps
22261 Launcher
23864 common-mistakes-0.0.1-SNAPSHOT.jar
15608 RemoteMavenServer
3623243 Main
23868 Jps

jinfo: 打印 JVM 的各种参数

➜  ~ jinfo 23864
Java System Properties:
#Wed Jan 29 12:49:47 CST 2020
...
user.name=zhuye
path.separator=\:
os.version=10.15.2
java.runtime.name=Java(TM) SE Runtime Environment
file.encoding=UTF-8
java.vm.name=Java HotSpot(TM) 64-Bit Server VM
...


VM Flags:
-XX:CICompilerCount=4 -XX:ConcGCThreads=2 -XX:G1ConcRefinementThreads=8 -XX:G1HeapRegionSize=1048576 -XX:GCDrainStackTargetSize=64 -XX:InitialHeapSize=268435456 -XX:MarkStackSize=4194304 -XX:MaxHeapSize=4294967296 -XX:MaxNewSize=2576351232 -XX:MinHeapDeltaBytes=1048576 -XX:NonNMethodCodeHeapSize=5835340 -XX:NonProfiledCodeHeapSize=122911450 -XX:ProfiledCodeHeapSize=122911450 -XX:ReservedCodeCacheSize=251658240 -XX:+SegmentedCodeCache -XX:+UseCompressedClassPointers -XX:+UseCompressedOops -XX:+UseG1GC


VM Arguments:
java_command: common-mistakes-0.0.1-SNAPSHOT.jar -Xms1g -Xmx1g
java_class_path (initial): common-mistakes-0.0.1-SNAPSHOT.jar
Launcher Type: SUN_STANDARD

jstack: 打印JVM的线程栈和锁情况

类似于Arthas的 thread 命令

➜  ~ jstack 23940
2020-01-29 13:08:15
Full thread dump Java HotSpot(TM) 64-Bit Server VM (11.0.3+12-LTS mixed mode):

...

"main" #1 prio=5 os_prio=31 cpu=440.66ms elapsed=574.86s tid=0x00007ffdd9800000 nid=0x2803 waiting on condition  [0x0000700003849000]
   java.lang.Thread.State: TIMED_WAITING (sleeping)
  at java.lang.Thread.sleep(java.base@11.0.3/Native Method)
  at java.lang.Thread.sleep(java.base@11.0.3/Thread.java:339)
  at java.util.concurrent.TimeUnit.sleep(java.base@11.0.3/TimeUnit.java:446)
  at org.geekbang.time.commonmistakes.troubleshootingtools.jdktool.CommonMistakesApplication.main(CommonMistakesApplication.java:41)
  at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(java.base@11.0.3/Native Method)
  at jdk.internal.reflect.NativeMethodAccessorImpl.invoke(java.base@11.0.3/NativeMethodAccessorImpl.java:62)
  at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(java.base@11.0.3/DelegatingMethodAccessorImpl.java:43)
  at java.lang.reflect.Method.invoke(java.base@11.0.3/Method.java:566)
  at org.springframework.boot.loader.MainMethodRunner.run(MainMethodRunner.java:48)
  at org.springframework.boot.loader.Launcher.launch(Launcher.java:87)
  at org.springframework.boot.loader.Launcher.launch(Launcher.java:51)
  at org.springframework.boot.loader.JarLauncher.main(JarLauncher.java:52)

"Thread-1" #13 prio=5 os_prio=31 cpu=17851.77ms elapsed=574.41s tid=0x00007ffdda029000 nid=0x9803 waiting on condition  [0x000070000539d000]
   java.lang.Thread.State: TIMED_WAITING (sleeping)
  at java.lang.Thread.sleep(java.base@11.0.3/Native Method)
  at java.lang.Thread.sleep(java.base@11.0.3/Thread.java:339)
  at java.util.concurrent.TimeUnit.sleep(java.base@11.0.3/TimeUnit.java:446)
  at org.geekbang.time.commonmistakes.troubleshootingtools.jdktool.CommonMistakesApplication.lambda$null$1(CommonMistakesApplication.java:33)
  at org.geekbang.time.commonmistakes.troubleshootingtools.jdktool.CommonMistakesApplication$$Lambda$41/0x00000008000a8c40.run(Unknown Source)
  at java.lang.Thread.run(java.base@11.0.3/Thread.java:834)

jmap: 堆内存分析工具

类似于 Arthas的 heapdump 命令，用于生成 heap dump 文件。

如果不使用这个命令，还可以使用 -XX:+HeapDumpOnOutOfMemoryError 参数来让虚拟机出现 OOM 的时候，自动生成 dump 文件。

jmap -dump:live,format=b,file=heap.hprof 6268

生成dump文件我们可以使用eclipse的MAT，jdk自带的jvisualvm分析内存泄露和内存溢出问题；

使用MAT查看dump文件见阿里开源Java诊断工具 Arthas 使用

jstat: 监控jvm的性能指标，常用查看GC回收

类似于

用于查看JVM中堆的垃圾收集情况的统计

[root@hadoop ~]# jstat -gc 3346 
 S0C    S1C    S0U    S1U      EC       EU        OC         OU       MC     MU    CCSC   CCSU   YGC     YGCT    FGC    FGCT     GCT  
128.0  128.0   0.0   128.0   1024.0   919.8    15104.0     2042.4   8448.0 8130.4 1024.0 996.0       7    0.019   0      0.000    0.019