I have the following code ,

```
import java.util.Arrays;

public class ParellelStream {

    public static void main(String args[]){
        Double dbl[] = new Double[1000000];
        for(int i=0; i<dbl.length;i++){
            dbl[i]=Math.random();
        }

        long start = System.currentTimeMillis();
        Arrays.parallelSort(dbl);
        System.out.println("time taken :"+((System.currentTimeMillis())-start));

    }

}

```

When I run this code it takes time approx 700 to 800 ms, but when I replace the line Arrays.parallelSort to Arrays.sort it takes 500 to 600 ms. I read about the Arrays.parallelSort and Arrays.sort method which says that Arrays.parellelSort gives poor performance when dataset are small but here I am using array of 1000000 elements. what could be the reason for parallelSort poor performance ?? I am using java8.