큰 대상을 정의하여 OLD 구역에 직접 넣는다(대상이 차지하는 메모리가 전체 설정의 절반 이상), FGC가 발생하기 쉽다
2954 단어 Java 기초 학습
public class GcDemo {
private static List list = new ArrayList();
public static void main(String[] args) throws Exception {
Thread.sleep(10000 * 2);
happenMinorGC(111);
}
private static void happenMinorGC(int happenMinorGCIndex) throws Exception {
for (int i = 0; i < happenMinorGCIndex; i++) {
Thread.sleep(1000);
MemoryObject m = new MemoryObject(1024 * 1024 * 7);
list.add(m );
if(list.size() >= 4){
System.out.println('5');
list.clear();
}
}
}
}
class MemoryObject {
private byte[] bytes;
public MemoryObject(int objectSize) {
this.bytes = new byte[objectSize];
}
}
분석:java-XX:+UseSerialGC-Xms40M-Xmx40M-Xmn16M-verbose:gc-X:+PrintGCDetails-X:SurvivorRatio=6GcDemo 실행:FGC 발생
S0 S1 E O P YGC YGCT FGC FGCT GCT 0.00 0.00 2.00 0.00 10.65 0 0.000 0 0.000 0.000 0.00 0.00 2.00 0.00 10.65 0 0.000 0 0.000 0.000 0.00 0.00 2.00 0.00 10.65 0 0.000 0 0.000 0.000 0.00 0.00 2.00 0.00 10.65 0 0.000 0 0.000 0.000 0.00 0.00 2.00 0.00 10.65 0 0.000 0 0.000 0.000 0.00 0.00 60.33 0.00 10.66 0 0.000 0 0.000 0.000 0.00 5.68 60.33 29.17 10.70 1 0.007 0 0.000 0.007 5.68 0.00 58.33 58.33 10.70 2 0.013 0 0.000 0.013 0.00 5.68 59.37 87.50 10.70 3 0.020 0 0.000 0.020 0.00 0.00 58.33 0.47 10.70 4 0.020 1 0.003 0.023 0.00 0.00 58.33 29.64 10.70 5 0.023 1 0.003 0.026 0.00 0.00 58.33 58.81 10.70 6 0.028 1 0.003 0.031 0.00 0.00 59.02 87.97 10.70 7 0.031 1 0.003 0.035 0.00 0.00 58.33 0.47 10.70 8 0.031 2 0.007 0.038 0.00 0.00 58.33 29.64 10.70 9 0.035 2 0.007 0.041 0.00 0.00 58.33 58.81 10.70 10 0.038 2 0.007 0.045 0.00 0.00 58.79 87.97 10.70 11 0.042 2 0.007 0.048 0.00 0.00 58.33 0.47 10.70 12 0.042 3 0.010 0.052 0.00 0.00 58.33 29.64 10.70 13 0.046 3 0.010 0.056 0.00 0.00 58.33 58.81 10.70 14 0.049 3 0.010 0.059 0.00 0.00 58.63 87.97 10.70 15 0.053 3 0.010 0.063 0.00 0.00 58.33 0.47 10.69 16 0.053 4 0.014 0.067 0.00 0.00 58.33 29.64 10.69 17 0.057 4 0.014 0.071 0.00 0.00 58.33 58.81 10.69 18 0.061 4 0.014 0.017 0.00 0.00 58.53 87.97 10.69 19 0.064 4 0.064 0.078 0.00 58.33 0.47 10.69 20 0.064 5 0.017 0.081 참조:http://xianqi-h.iteye.com/blog/1346491