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JVM调优实战

 3 years ago
source link: https://duanguangguang.github.io/2020/04/18/jvm/jvm-optime/
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JVM调优实战

发表于 2020-04-18

| 分类于 jvm

| 0 Comments

| 阅读次数: 13

介绍JVM调优。

非堆内存：

  • Socket句柄
  • 数据库连接

一、JVM调优原则

  • 降低Full GC的频率，一天有1-2次，控制在晚上，重启服务器或者定时任务出发Full GC

  • 确保大多数对象朝生夕死

  • 提高大对象进入老年代的门槛（-XX:MaxTenuringThreshold=15）

  • -Xms500m -Xmx500m设置成一样

    最小堆内存，最大堆内存，减少扩容过程耗时

  • CMSInitiatingOccupancyFraction=（老年代-Eden-1个Survivor）/（老年的-新生代）*100

    设置CMS收集器在老年代空间被使用多少后出发垃圾收集。

  • CMS调优示例

    -server -Xmn500m -Xms1200m -Xmx1200m -XX:PermSize=256m -XX:MaxPermSize=256m
    -XX:SurvivorRation=1 -XX:+UseConcMarkSweepGC -XX:CMSInitiatingOccupancyFraction=70 
    -XX:+UseCMSCompactAtFullCollection -XX:+CMSFullGCsBeforeCompaction=5
    -XX:+HeapDumpOnOutOfMemoryError -Xloggc:log/gc.log -XX:+PrintGCDetails
    -XX:+CMSParallelRamarkEnabled
    • jstat -gc 2924
    • jstat -gccause 2924 1000
    • jstat -class 2924

report

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