Shulou(Shulou.com)06/03 Report--

Preface

JVM is the abbreviation of Java Virtual Machine (Java Virtual Machine). JVM is a specification for computing devices. It is a fictional computer, which is realized by simulating various computer functions on a real computer.

With the introduction of the Java language virtual machine, the Java language does not need to be recompiled when it runs on different platforms. The Java language uses the Java virtual machine to shield the information related to the specific platform, so that the Java language compiler only needs to generate the object code (bytecode) running on the Java virtual machine and can run on a variety of platforms without modification.

I. background

When using JMeter to stress test the HTTP interface, the response is very slow.

Second, the train of thought of positioning

1. Locate the time-consuming SQL

View Druid Monitor

2. Locate jvm parameters

(1) View the configuration information of the linux server

# Linux to view the kernel information of the current operating system

Uname-a

# Linux to view current operating system version information

Cat / proc/version

# Linux to view the current operating system release information of the version

Cat / etc/issue or cat / etc/redhat-release

# Linux to view cpu related information, including model, main frequency, kernel information, etc.

Cat / proc/cpuinfo

# Linux View version indicates that CPU is running in 32bit mode, but it does not mean that CPU does not support 64bit

Getconf LONG_BIT

# check the usage of the hard disk

Df-h

# check memory usage

Free-m

fourteen

(2) memory usage of jvm

Jps

Jstat

Jinfo

Jmap

Jhat

Jstack

Third, the idea of optimization

(1) mysql

Establish a primary key

Build an index

(2) tomcat middleware

Adjust the parameters of server.xml, such as configuration-Xms4096M-Xmx4096M

# Register custom URL handlers

# Do this here so custom URL handles (specifically 'war:...') Can be used in the security policy

JAVA_OPTS= "$JAVA_OPTS-Djava.protocol.handler.pkgs=org.apache.catalina.webresources-Xms4096M-Xmx4096M"

one

two

three

(3) jvm

Adjust the Xmx and Xms of catalina.sh

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