Python：subprocess32 process.stdout.readline()等待时间

import subprocess32 as subprocess
def run(command):
    process = subprocess.Popen(command,stdout=subprocess.PIPE,stderr=subprocess.STDOUT)
    try:
        while process.poll() == None:
            print process.stdout.readline()
    finally:
        # Handle the scenario if the parent
        # process has terminated before this subprocess
        if process.poll():
            process.kill()

但是,如果我使用下面的python示例程序,它似乎停留在process.poll()或process.stdout.readline()上,直到程序完成.我认为它是stdout.readline(),因为如果我将输出的字符串数量从10增加到10000(在示例程序中)或者在每次打印后添加到sys.stdout.flush()中,则在运行中打印函数确实被执行了.

如何使子进程的输出更加实时？

注意：我刚刚发现python示例程序在输出时不执行sys.stdout.flush(),是否有一种方法让子进程的调用者以某种方式强制执行此操作？

每5秒输出10个字符串的示例程序.

#!/bin/env python
import time

if __name__ == "__main__":

    i = 0
    start = time.time()
    while True:
        if time.time() - start >= 5:
            for _ in range(10):
                print "hello world" + str(i)
            start = time.time()
            i += 1
        if i >= 3:
            break