Java NIO Pipe vs BlockingQueue

Question

I just discovered that just has an NIO facility, Java NIO Pipe that\'s designed for passing data between threads. Is there any advantage of using this mechanism over the more co

Answer 1

So after having a lot of trouble with pipe (check here) I decided to favor non-blocking concurrent queues over NIO pipes. So I did some benchmarks on Java's ConcurrentLinkedQueue. See below:

public static void main(String[] args) throws Exception {

    ConcurrentLinkedQueue queue = new ConcurrentLinkedQueue();

    // first test nothing:

    for (int j = 0; j < 20; j++) {

        Benchmarker bench = new Benchmarker();

        String s = "asd";

        for (int i = 0; i < 1000000; i++) {
            bench.mark();
            // s = queue.poll();
            bench.measure();
        }

        System.out.println(bench.results());

        Thread.sleep(100);
    }

    System.out.println();

    // first test empty queue:

    for (int j = 0; j < 20; j++) {

        Benchmarker bench = new Benchmarker();

        String s = "asd";

        for (int i = 0; i < 1000000; i++) {
            bench.mark();
            s = queue.poll();
            bench.measure();
        }

        System.out.println(bench.results());

        Thread.sleep(100);
    }

    System.out.println();

    // now test polling one element on a queue with size one

    for (int j = 0; j < 20; j++) {

        Benchmarker bench = new Benchmarker();

        String s = "asd";
        String x = "pela";

        for (int i = 0; i < 1000000; i++) {
            queue.offer(x);
            bench.mark();
            s = queue.poll();
            bench.measure();
            if (s != x) throw new Exception("bad!");
        }

        System.out.println(bench.results());

        Thread.sleep(100);
    }

    System.out.println();

    // now test polling one element on a queue with size two

    for (int j = 0; j < 20; j++) {

        Benchmarker bench = new Benchmarker();

        String s = "asd";
        String x = "pela";

        for (int i = 0; i < 1000000; i++) {
            queue.offer(x);
            queue.offer(x);
            bench.mark();
            s = queue.poll();
            bench.measure();
            if (s != x) throw new Exception("bad!");
            queue.poll();
        }

        System.out.println(bench.results());

        Thread.sleep(100);
    }
}

The results:

totalLogs=1000000, minTime=0, maxTime=85000, avgTime=58.61 (times in nanos)
totalLogs=1000000, minTime=0, maxTime=5281000, avgTime=63.35 (times in nanos)
totalLogs=1000000, minTime=0, maxTime=725000, avgTime=59.71 (times in nanos)
totalLogs=1000000, minTime=0, maxTime=25000, avgTime=58.13 (times in nanos)
totalLogs=1000000, minTime=0, maxTime=378000, avgTime=58.45 (times in nanos)
totalLogs=1000000, minTime=0, maxTime=15000, avgTime=57.71 (times in nanos)
totalLogs=1000000, minTime=0, maxTime=170000, avgTime=58.11 (times in nanos)
totalLogs=1000000, minTime=0, maxTime=1495000, avgTime=59.87 (times in nanos)
totalLogs=1000000, minTime=0, maxTime=232000, avgTime=63.0 (times in nanos)
totalLogs=1000000, minTime=0, maxTime=184000, avgTime=57.89 (times in nanos)

totalLogs=1000000, minTime=0, maxTime=2600000, avgTime=65.22 (times in nanos)
totalLogs=1000000, minTime=0, maxTime=850000, avgTime=60.5 (times in nanos)
totalLogs=1000000, minTime=0, maxTime=150000, avgTime=63.83 (times in nanos)
totalLogs=1000000, minTime=0, maxTime=43000, avgTime=59.75 (times in nanos)
totalLogs=1000000, minTime=0, maxTime=276000, avgTime=60.02 (times in nanos)
totalLogs=1000000, minTime=0, maxTime=457000, avgTime=61.69 (times in nanos)
totalLogs=1000000, minTime=0, maxTime=204000, avgTime=60.44 (times in nanos)
totalLogs=1000000, minTime=0, maxTime=154000, avgTime=63.67 (times in nanos)
totalLogs=1000000, minTime=0, maxTime=355000, avgTime=60.75 (times in nanos)
totalLogs=1000000, minTime=0, maxTime=338000, avgTime=60.44 (times in nanos)

totalLogs=1000000, minTime=0, maxTime=345000, avgTime=110.93 (times in nanos)
totalLogs=1000000, minTime=0, maxTime=396000, avgTime=100.32 (times in nanos)
totalLogs=1000000, minTime=0, maxTime=298000, avgTime=98.93 (times in nanos)
totalLogs=1000000, minTime=0, maxTime=1891000, avgTime=101.9 (times in nanos)
totalLogs=1000000, minTime=0, maxTime=254000, avgTime=103.06 (times in nanos)
totalLogs=1000000, minTime=0, maxTime=1894000, avgTime=100.97 (times in nanos)
totalLogs=1000000, minTime=0, maxTime=230000, avgTime=99.21 (times in nanos)
totalLogs=1000000, minTime=0, maxTime=348000, avgTime=99.63 (times in nanos)
totalLogs=1000000, minTime=0, maxTime=922000, avgTime=99.53 (times in nanos)
totalLogs=1000000, minTime=0, maxTime=168000, avgTime=99.12 (times in nanos)

totalLogs=1000000, minTime=0, maxTime=686000, avgTime=107.41 (times in nanos)
totalLogs=1000000, minTime=0, maxTime=320000, avgTime=95.58 (times in nanos)
totalLogs=1000000, minTime=0, maxTime=248000, avgTime=94.94 (times in nanos)
totalLogs=1000000, minTime=0, maxTime=217000, avgTime=95.01 (times in nanos)
totalLogs=1000000, minTime=0, maxTime=159000, avgTime=93.62 (times in nanos)
totalLogs=1000000, minTime=0, maxTime=155000, avgTime=95.28 (times in nanos)
totalLogs=1000000, minTime=0, maxTime=106000, avgTime=98.57 (times in nanos)
totalLogs=1000000, minTime=0, maxTime=370000, avgTime=95.01 (times in nanos)
totalLogs=1000000, minTime=0, maxTime=1836000, avgTime=96.21 (times in nanos)
totalLogs=1000000, minTime=0, maxTime=212000, avgTime=98.62 (times in nanos)

Conclusion:

The maxTime can be scary but I think it is safe to conclude we are in the 50 nanos range for polling a concurrent queue.