虚拟机间延迟测量_简单的类来测量延迟

虚拟机间延迟测量

这是我编写的用于测量延迟的非常简单的类。 HDRHistogram不是劳斯莱斯解决方案，但是如果您只想在项目中添加一个类，那么效果就很好。

这是一个简单的测试程序，向您展示其用法：

package util;public class LatencyMeasureExample {public static void main(String[] args) throws InterruptedException{//Below are a couple of examplesLatencyMeasure lm = new LatencyMeasure(1000000);System.out.println("Thread.sleep() random");for (int i = 0; i < 100000; i++) {lm.startMeasure();Thread.sleep((long)Math.random()*10);lm.endMeasure();}lm.printStats();lm = new LatencyMeasure(1000000);double d = 0;System.out.println("\nMath.sqrt");for (int i = 0; i < 100000; i++) {lm.startMeasure();d+=Math.sqrt(i);lm.endMeasure();}lm.printStats();}
}

这是一些示例输出：

Thread.sleep() random
Latency measured:0.32 us for 50 percentile0.44 us for 90 percentile0.68 us for 99 percentile26.82 us for 99.9 percentile582.66 us for 99.99 percentile2024.92 us worst percentile
Math.sqrt
Latency measured:0.04 us for 50 percentile0.06 us for 90 percentile0.09 us for 99 percentile0.12 us for 99.9 percentile0.20 us for 99.99 percentile28.17 us worst percentile

只有4种方法：

构造函数：这需要一个int表示要测量的最大次数。除了对内存的影响外，过大的大小也不是问题。在此实现中，您至少需要进行10,000次测量才能使代码正常工作。如果您想花更少的钱，只需在printStats（）中适当调整代码即可。
在要测量的代码的任一侧调用startMeasure（）和endMeasure（）。
printStats（）打印出结果。

实施如下：

package util;import java.util.Arrays;public class LatencyMeasure {private long[] times;private long time;private int index=0;public LatencyMeasure(int maxCapacity) {times = new long[maxCapacity];for (int i = 0; i < times.length; i++) {times[i] = -1;}}public void startMeasure(){time = System.nanoTime();}public void endMeasure() {times[index++] = System.nanoTime()-time;}public void printStats() {int filled = 0;for (int i = 0; i < times.length; i++) {if (times[i] == -1) {filled = i;break;}}long[] popTimes = new long[filled];System.arraycopy(times, 0, popTimes, 0, filled);Arrays.sort(popTimes);System.out.printf("Latency measured: \n" +" %.2f us for 50 percentile\n" +" %.2f us for 90 percentile\n" +" %.2f us for 99 percentile\n" +" %.2f us for 99.9 percentile\n" +" %.2f us for 99.99 percentile\n" +" %.2f us worst percentile\n",popTimes[popTimes.length / 2] / 1e3,popTimes[popTimes.length * 9 / 10] / 1e3,popTimes[popTimes.length - popTimes.length / 100] / 1e3,popTimes[popTimes.length - popTimes.length / 1000] / 1e3,popTimes[popTimes.length - popTimes.length / 10000] / 1e3,popTimes[popTimes.length - 1] / 1e3);}
}