#coding=utf-8from multiprocessing import Poolimport os, time, randomdef run_task(name):    print 'Task %s (pid = %s) is running...' % (name, os.getpid())    time.sleep(random.random() * 5)    print 'Task %s end.' % nameif __name__ == '__main__':    print 'Current process %s.' % os.getpid()    p = Pool(processes =  3)    for i in range(10):        p.apply_async(run_task, i)    print 'Waiting for all subprocesses done...'    p.close()    p.join()    print "All subprocesses done."#join()方法会等待所有的进程执行完毕， 调用join（）之前必须先调用close（）#调用close（）之后，进程池便无法再添加新的进程