JVM family -- monitoring tools

stay linux In the environment

One .uptime

system time , The elapsed time

The number of connections :

Each terminal is a connection

1,5,15 Average system load in minutes  

Average number of processes in the run queue  

Two .vmstat

Can count the system's CPU, Memory ,swap,io , etc.

vmstat 1 4

3、 ... and .top

cpu Memory

Each process takes up CPU situation

Four .pidstat

monitor CPU,IO, Memory

-p Specify process –u monitor CPU Samples per second altogether 3 Time -t Show threads

TID Threads id   CPU Which core

5、 ... and .windows

Task manager :cpu ,io

perfmon

pslist: Show java The operation of the program

6、 ... and .java Bring their own tools

1.jps

List java process , -q Only output processes id  -m Output Java process （ The main function ） Parameters of   -l Can be used to output the full path of the main function   -v Can be displayed and passed to JVM Parameters of

2.jinfo

see java Extension parameters for the application

-flag <name>： Print assignments JVM Parameter values for

-flag [+|-]<name>： Set the specified JVM Boolean value of parameter

-flag <name>=<value>： Set the specified JVM The value of the parameter  

jinfo -flag PrintGCDetails 2972

3.jmap

Generate java Heap snapshots of applications and statistics of objects

4.jstack

Print thread dump

-l Print lock information -m Print java and native Frame information of -F mandatory dump, When jstack Use when there is no response

5.JConsole

Graphical monitoring tools

You can see Java Running overview of the application , Monitoring heap information 、 Use of permanent areas 、 Class loading, etc  

6.Visual VM

Visual VM It is a powerful visual tool for multi in one fault diagnosis and performance monitoring  

7、 ... and . Example

Run a program ThreadBlockMain, Expected output Hello,World , The result is after the program runs , Program stuck , No expected output . 

1.jps View program progress

2.jstack Output dump

3.top View occupancy cpu Most of the processes id

4.pidstat Check the process id The next thread is occupied cpu most ,TID Threads id convert to 16 Base number ,nid

5.jstack process id  Output information , lookup nid, Location problem