jvm堆参数调整

堆内存调优：

默认：(个人电脑内存为16G)

图片.png

/**
 * @author ：yuanyong
 * @date ：2021/1/27 16:01
 * @description：  
 */
public class HeapArgs {
    public static void main(String[] args) {
        long maxMemory = Runtime.getRuntime().maxMemory();//java虚拟机试图使用的最大内存
        long totalMemory = Runtime.getRuntime().totalMemory();//java虚拟机的内存总量

        System.out.println("-Xmx:MAX_MEMORY = "+maxMemory/(double)1024/1024+"MB");
        System.out.println("-Xms:TOTAL_MEMORY = "+totalMemory/(double)1024/1024+"MB");
    }
}
************************************************************************
-Xmx:MAX_MEMORY = 3591.5MB
-Xms:TOTAL_MEMORY = 243.5MB

参数调优：
格式：-Xms1024m -Xmx1024m -XX:+PrintGCDetails

图片.png

重新执行程序：

-Xmx:MAX_MEMORY = 981.5MB
-Xms:TOTAL_MEMORY = 981.5MB
Heap
 PSYoungGen      total 305664K, used 20971K [0x00000000eab00000, 0x0000000100000000, 0x0000000100000000)
  eden space 262144K, 8% used [0x00000000eab00000,0x00000000ebf7afb8,0x00000000fab00000)
  from space 43520K, 0% used [0x00000000fd580000,0x00000000fd580000,0x0000000100000000)
  to   space 43520K, 0% used [0x00000000fab00000,0x00000000fab00000,0x00000000fd580000)
 ParOldGen       total 699392K, used 0K [0x00000000c0000000, 0x00000000eab00000, 0x00000000eab00000)
  object space 699392K, 0% used [0x00000000c0000000,0x00000000c0000000,0x00000000eab00000)
 Metaspace       used 3248K, capacity 4496K, committed 4864K, reserved 1056768K
  class space    used 351K, capacity 388K, committed 512K, reserved 1048576K