小编pet*_*ang的帖子

我想检查多线程是否比单线程快，然后我在这里做一个演示：

public class ThreadSpeedTest {

    /**
     * @param args
     */
    public static void main(String[] args) {
        System.out.println("cpu number:"
                + Runtime.getRuntime().availableProcessors());
        singleThreadStart();
//      secondThreadStart();
//      fiveThreadStart();
    }

    private static void sum() {
        long sum = 0;
        for (int i = 0; i < 1000000; i++) {
            sum += i;
        }
        System.out.println(sum);
    }

    private static void singleThreadStart() {
        new Thread(new Runnable() {

            public void run() {
                long start = System.nanoTime();
    //          sum();
    //          sum();
    //          sum();
                sum();
                sum();
                long end = System.nanoTime(); …