IdleThreadsParked.java

  @Param({ "0" })
  int idleThreads;
  Thread[] pool;

  @Setup
  public final void bakeACake() {
    if (idleThreads != 0) {
      pool = new Thread[idleThreads];
      for (int i = 0; i < idleThreads; i++) {
        pool[i] = new Thread(() -> {
          parkDeep(256);
        });
        pool[i].setDaemon(true);
        pool[i].start();
      }
    }
  }

  static void parkDeep(int i) {
    if (i == 0) {
      LockSupport.park();
    } else {
      parkDeep(i - 1);
    }
  }

  @Override
  protected Object safepointMethod() {
    return ManagementFactory.getThreadMXBean().dumpAllThreads(false, false);
  }