Idea 打印GC

设置

• Run => Edit Configurations => VM options

  • 添加 -XX:+PrintGCDetails

• 

• 

• 运行程序后会在末尾打印GC信息

  2019-11-02 13:07:47 INFO  ShutdownHookManager:54 - Deleting directory C:UsersMSI-PCAppDataLocalTempspark-201c381b-dad9-43ae-8bfc-cb27de67010f
  Heap
   PSYoungGen    total 87552K, used 64517K [0x000000076b780000, 0x0000000771800000, 0x00000007c0000000)
    eden space 78336K, 79% used [0x000000076b780000,0x000000076f407838,0x0000000770400000)
    from space 9216K, 27% used [0x0000000770d80000,0x0000000770ff9ed8,0x0000000771680000)
    to   space 9728K, 0% used [0x0000000770400000,0x0000000770400000,0x0000000770d80000)
   ParOldGen       total 109568K, used 10117K [0x00000006c2600000, 0x00000006c9100000, 0x000000076b780000)
    object space 109568K, 9% used [0x00000006c2600000,0x00000006c2fe1548,0x00000006c9100000)
   Metaspace       used 41925K, capacity 42508K, committed 42712K, reserved 1085440K
    class space    used 6126K, capacity 6259K, committed 6360K, reserved 1048576K
  
  Process finished with exit code 0
  

  • PSYoungGen(Parallel Scavenge): Eden + FromSpace
  • 完整的YoungGeneration: Eden+FromSpace+ToSpace
  • ParOldGen(Par => Parameter, Parameter of Old Generation): GC 回收前后老年代的参数变化
  • object space: 对象空间
  • Metaspace: 元空间 (使用, 容量, 提交了多少, 保存了多少)
  • Class space: 类空间 (同上)