Java Performance Tuning

One, Tomcat server 1, JVM parameter tuning

The startup parameters of Tomcat are located in the Tomcat directory \ Bin, if you are the Linux operating system is the catalina.sh file, if you are a Windows operating system then you need to change the Catalina.bat file

JAVA_OPTS="$JAVA_OPTS -server -Xms4096m -Xmx4096m -Xmn1024m -Xss256K -XX:+DisableExplicitGC -XX:MaxTenuringThreshold=15 -XX:+UseParNewGC -XX:+UseConcMarkSweepGC -XX:+CMSParallelRemarkEnabled -XX:+UseCMSCompactAtFullCollection -XX:LargePageSizeInBytes=128m -XX:+UseFastAccessorMethods -XX:+UseCMSInitiatingOccupancyOnly -XX:CMSInitiatingOccupancyFraction=70 -XX:+PrintGC -XX:+PrintGCDetails -XX:+PrintGCDateStamps -Xloggc:/home/gclogs/gc.log -Djava.awt.headless=true"

Explain:
-server: Higher performance
-xms4096m: initial heap Memory 4g
-xmx4096m: Max heap Memory 4g
-xmn1024m: Young generation 1g
-xss256k: space occupied by each thread
-XX:+DISABLEEXPLICITGC: Suppress call to GC
-xx:maxtenuringthreshold=15: Survival times in younger generations
-XX:+USEPARNEWGC: Multi-threaded parallel recycling for younger generations
-XX:+USECONCMARKSWEEPGC: Old generation uses CMS recycling
-xx:+cmsparallelremarkenabled: Minimize Mark's time when using USEPARNEWGC
-xx:+usecmscompactatfullcollection: Prevents Memoryfragmention, organizes live object, and reduces memory fragmentation when using concurrent GC
-xx:largepagesizeinbytes=128m: Specify paging page size for Java heap
-xx:+usefastaccessormethods:get,set method into local code
-xx:+usecmsinitiatingoccupancyonly: Indicates that only after oldgeneration has used the initialized scale concurrent collector start the collection
-XX:CMSINITIATINGOCCUPANCYFRACTION=70: Old generation arrives at 70% for GC
-djava.awt.headless=true:headless mode is a configuration mode of the system. In this mode, the system is missing a display device, keyboard, or mouse.
-xx:+printgc-xx:+printgcdetails-xx:+printgcdatestamps-xloggc:/home/gclogs/gc.log: Print log information

Remark: The above collector is young substitute parnewgc, old substitute CMS; You can also use the G1 collector

-XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -XX:MaxGCPauseMillis=50 -XX:GCPauseIntervalMillis=200

Explain:
-XX:+UNLOCKEXPERIMENTALVMOPTIONS-XX:+USEG1GC #开启G1, these two are used simultaneously
-xx:maxgcpausemillis=50 #暂停时间目标;
-xx:gcpauseintervalmillis=200 #暂停间隔目标;

2, connector optimization

The installation directory for Tomcat \conf the following server.xml

<Connector port="8080"protocol="HTTP/1.1"connectionTimeout="20000"URIEncoding="UTF-8"maxThreads="300"minSpareThreads="25"maxSpareThreads="75"enableLookups="false"acceptCount="300"maxProcessors="1000"minProcessors="5"useURIValidationHack="false"compression="on"compressionMinSize="2048"compressableMimeType="text/html,text/xml,text/JavaScript,text/css,text/plain"redirectPort="8443" />

Explain:
Protocol: Protocol
ConnectionTimeout: Number of milliseconds to connect time-out
Uriencoding: Encoding
Maxthreads:tomcat the maximum number of threads that can be created, that is, the maximum number of concurrent
Minsparethreads: The minimum number of standby threads, the number of threads initialized at tomcat startup.
Maxsparethreads: If the number of threads in the idle state is greater than the number of settings, the threads are aborted, reducing the total number of threads in the pool
Enablelookups: Whether to allow domain names to be reversed
Acceptcount: When the number of threads reaches MaxThreads, subsequent requests are placed in a wait queue, the Acceptcount is the size of the queue, and if the queue is full, refuse connection
Maxprocessors: Maximum number of connections
Minprocessors: Initialize the number of connections
Useurivalidationhack: Checking URLs
Compression: Boot compression
compressionminsize:2048 when the return content is greater than or equal to 2kb boot compression, to the client in the decompression
Compressablemimetype: Compression type

Ii. springboot Item 1, JVM parameters

Springboot starts directly with the jar package and adds parameters to the start command, here is an example:

nohup java -server -Xms4096m -Xmx4096m -Xmn1024m -Xss256K -XX:+DisableExplicitGC -XX:MaxTenuringThreshold=15 -XX:+UseParNewGC -XX:+UseConcMarkSweepGC -XX:+CMSParallelRemarkEnabled -XX:+UseCMSCompactAtFullCollection -XX:LargePageSizeInBytes=128m -XX:+UseFastAccessorMethods -XX:+UseCMSInitiatingOccupancyOnly -XX:CMSInitiatingOccupancyFraction=70 -XX:+PrintGC -XX:+PrintGCDetails -XX:+PrintGCDateStamps -Xloggc:/home/gclogs/gc.log -Djava.awt.headless=true -jar mq.jar &

2. Springboot optimized for built-in Tomcat

Configuring in Application.yml

server:  tomcat:    uri-encoding: UTF-8    max-threads: 300    min-spare-threads: 25    max-connections: 1000    accept-count: 300  port: 8080  connection-timeout: 20000  compression:    enabled: true    mime-types: text/html,text/xml,text/JavaScript,text/css,text/plain    min-response-size: 2048

Third, Performance view common commands

Note: 128914 is the thread ID
View load: W, uptime
View Cpu:top
Memory: Free
Disk: DF
Io:iostat, Vmstat
View GC Status: JSTAT-GC 128914 2000 2
View stack condition: Jstack 128914
Analyzing GC logs: more Gc.log
View all threads inside a process: top-hp 128914

Java Performance Tuning