pythonのgevent同步异步区别

#!/usr/bin/env python

from urllib import  request
import  gevent
from gevent import monkey
import time

monkey.patch_all() # 把当前程序所有的IO操作给我单独的做上标记。
def f(url):
    resp = request.urlopen(url)
    data = resp.read()
    print(len(data))

urls = ["https://www.python.org",
        "https://www.yahoo.com",
        "https://github.com"
        ]
time_start = time.time()
for url in urls:
    f(url)
print("同步花费时间：",time.time()-time_start)

asy_time = time.time()
gevent.joinall({
    gevent.spawn(f,"https://www.python.org"),
    gevent.spawn(f,"https://www.yahoo.com"),
    gevent.spawn(f,"https://github.com"),
})
print("异步花费时间：",time.time()-asy_time)

C:UsersAdministratorAppDataLocalProgramsPythonPython37python.exe D:/PythonStudy/charm/01/day10/爬虫.py
48822
479812
64096
同步花费时间： 4.925281763076782
48822
64096
477025
异步花费时间： 3.1961827278137207

Process finished with exit code 0