[AWS][EC2][Java] AWSのDNSクォータをテスト

TestDnsQuotaByInetAddress.java

// Command: java -Dsun.net.inetaddr.ttl=0 TestDnsQuotaByInetAddress 172.30.3.11
// Metric: ethtool -S eth0 | grep linklocal_allowance_exceeded
public class TestDnsQuotaByInetAddress {
  private static final int TRIALS = 10_000;
  private static final int THREADS = 1_024;
  private static final int LOG_THRESHOLD = 1_000;

  public static void main(String[] args) throws InterruptedException, ExecutionException {
    final String host = args[0];
    final ExecutorService executor = Executors.newFixedThreadPool(THREADS);
    final Object mutex = new Object();
    final List<Future<?>> futures = new ArrayList<>();

    long totalStartTime = System.currentTimeMillis();
    for (int i = 0; i < TRIALS; i++) {
      futures.add(executor.submit(() -> {
        try {
          long startTime = System.currentTimeMillis();
          InetAddress address = InetAddress.getByName(host);
          long initTime = System.currentTimeMillis();
          String hostAddress = address.getHostAddress();
          long addressTime = System.currentTimeMillis();
          String hostName = address.getHostName();
          long nameTime = System.currentTimeMillis();
          if (nameTime - startTime >= LOG_THRESHOLD) {
            synchronized (mutex) {
              System.out.println(String.format("%06d %05d %05d %05d %s %s",
                  System.currentTimeMillis() - totalStartTime, initTime - startTime, addressTime - initTime,
                  nameTime - addressTime, hostAddress, hostName));
            }
          }
          return null;
        } catch (Throwable e) {
          e.printStackTrace();
          System.exit(-1);
          return null;
        }
      }));
    }
    for (Future<?> res : futures) {
      res.get();
    }
    System.out.println(String.format("total: %d ms", System.currentTimeMillis() - totalStartTime));

    executor.shutdown();
  }
}