介绍一些jvm命令, 用来分析性能
- jps
查看目前jvm有哪些进程,得到进程id
root@hulk-5c7d968dcd-dxkx9:/# jps
1 war
13518 Jps
想这个进程id为1的就是当前的项目进程
- jstat -gc pid
查看gc情况
root@hulk-5c7d968dcd-dxkx9:/# jstat -gc 1
S0C S1C S0U S1U EC EU OC OU MC MU CCSC CCSU YGC YGCT FGC FGCT GCT
34944.0 34944.0 0.0 1941.7 279616.0 279384.9 699072.0 100063.8 107136.0 100602.0 12416.0 11314.7 967 20.738 4 1.011 21.749
每隔1000ms打印一次, 一共打印10次
root@hulk-5c7d968dcd-dxkx9:/# jstat -gc 1 1000 10
S0C S1C S0U S1U EC EU OC OU MC MU CCSC CCSU YGC YGCT FGC FGCT GCT
34944.0 34944.0 2587.6 0.0 279616.0 8109.1 699072.0 100134.6 107136.0 100602.0 12416.0 11314.7 968 20.747 4 1.011 21.758
34944.0 34944.0 2587.6 0.0 279616.0 8443.1 699072.0 100134.6 107136.0 100602.0 12416.0 11314.7 968 20.747 4 1.011 21.758
34944.0 34944.0 2587.6 0.0 279616.0 8496.8 699072.0 100134.6 107136.0 100602.0 12416.0 11314.7 968 20.747 4 1.011 21.758
34944.0 34944.0 2587.6 0.0 279616.0 8496.8 699072.0 100134.6 107136.0 100602.0 12416.0 11314.7 968 20.747 4 1.011 21.758
34944.0 34944.0 2587.6 0.0 279616.0 8545.5 699072.0 100134.6 107136.0 100602.0 12416.0 11314.7 968 20.747 4 1.011 21.758
34944.0 34944.0 2587.6 0.0 279616.0 8565.5 699072.0 100134.6 107136.0 100602.0 12416.0 11314.7 968 20.747 4 1.011 21.758
- jstack
查看线程
root@hulk-5c7d968dcd-dxkx9:/# top -Hp 1
top - 08:06:23 up 1113 days, 2:43, 0 users, load average: 2.33, 2.03, 2.01
Threads: 55 total, 0 running, 55 sleeping, 0 stopped, 0 zombie
%Cpu(s): 0.0 us, 3.4 sy, 0.0 ni, 96.6 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
MiB Mem : 15886.7 total, 566.7 free, 8520.5 used, 6799.6 buff/cache
MiB Swap: 0.0 total, 0.0 free, 0.0 used. 7031.6 avail Mem
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
1 root 20 0 3619560 871440 14672 S 0.0 5.4 0:00.00 java
5 root 20 0 3619560 871440 14672 S 0.0 5.4 0:21.68 java
6 root 20 0 3619560 871440 14672 S 0.0 5.4 0:19.69 VM Thread
7 root 20 0 3619560 871440 14672 S 0.0 5.4 0:00.08 Reference Handl
8 root 20 0 3619560 871440 14672 S 0.0 5.4 0:00.36 Finalizer
9 root 20 0 3619560 871440 14672 S 0.0 5.4 0:00.00 Signal Dispatch
10 root 20 0 3619560 871440 14672 S 0.0 5.4 3:49.42 C2 CompilerThre
11 root 20 0 3619560 871440 14672 S 0.0 5.4 0:35.26 C1 CompilerThre
12 root 20 0 3619560 871440 14672 S 0.0 5.4 0:00.00 Service Thread
13 root 20 0 3619560 871440 14672 S 0.0 5.4 0:53.67 VM Periodic Tas
18 root 20 0 3619560 871440 14672 S 0.0 5.4 0:00.00 XNIO-1 I/O-1
根据TIME+这一列得出哪个线程耗时最长
用命令查看该线程的十六进制值
root@hulk-5c7d968dcd-dxkx9:/# printf "%x\n" 40
28
查看是哪个类耗时的
root@hulk-5c7d968dcd-dxkx9:/# jstack 1 | grep 28
- parking to wait for <0x00000000d8bb6528> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
"XNIO-2 task-2" #37 prio=5 os_prio=0 tid=0x00007f84f4029800 nid=0x28 waiting on condition [0x00007f84f0734000]
- parking to wait for <0x00000000d6e228c0> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
"DestroyJavaVM" #32 prio=5 os_prio=0 tid=0x00007f852800a800 nid=0x5 waiting on condition [0x0000000000000000]
"XNIO-2 Accept" #30 prio=5 os_prio=0 tid=0x00007f85289d4000 nid=0x23 runnable [0x00007f84f1039000]
"XNIO-2 I/O-2" #29 prio=5 os_prio=0 tid=0x00007f85289d3800 nid=0x22 runnable [0x00007f84f113a000]
"XNIO-2 I/O-1" #28 prio=5 os_prio=0 tid=0x00007f8529ffd800 nid=0x21 runnable [0x00007f84f123b000]
"spring.cloud.inetutils" #22 daemon prio=5 os_prio=0 tid=0x00007f852895e800 nid=0x1b waiting on condition [0x00007f84f1a41000]
"AsyncAppender-Worker-ASYNC_LOGSTASH" #21 daemon prio=5 os_prio=0 tid=0x00007f8528d6f000 nid=0x1a waiting on condition [0x00007f84f2e45000]
"Service Thread" #7 daemon prio=9 os_prio=0 tid=0x00007f85280e2000 nid=0xc runnable [0x0000000000000000]
"C1 CompilerThread1" #6 daemon prio=9 os_prio=0 tid=0x00007f85280dd000 nid=0xb waiting on condition [0x0000000000000000]
"C2 CompilerThread0" #5 daemon prio=9 os_prio=0 tid=0x00007f85280db800 nid=0xa waiting on condition [0x0000000000000000]
"Signal Dispatcher" #4 daemon prio=9 os_prio=0 tid=0x00007f85280c7000 nid=0x9 runnable [0x0000000000000000]
"Finalizer" #3 daemon prio=8 os_prio=0 tid=0x00007f85280a4000 nid=0x8 in Object.wait() [0x00007f852cd52000]
"Reference Handler" #2 daemon prio=10 os_prio=0 tid=0x00007f852809f800 nid=0x7 in Object.wait() [0x00007f852ce53000]
"VM Thread" os_prio=0 tid=0x00007f8528095800 nid=0x6 runnable
"VM Periodic Task Thread" os_prio=0 tid=0x00007f85280e5000 nid=0xd waiting on condition
jstack -l 1 > 1.stack
导出线程文件