重新研究了一下 python 協程, 用 在 python2 中用 gevent/grequests 實現, 做了一些對比.
目的是想在 python2 的現有程式碼的基礎上, 在改動量最小的前提下實現協程.

grequests 也是用 gevent 實現的, 對 requests 進行了一些補丁修改.

#! -*- coding:utf8
import gevent
import threading
import urllib2
from timeit import timeit
import requests
#import grequests # grequests 會進行 patch_all(thread=False, select=False), 測試多執行緒後再 import
 

from queue import Queue

from gevent import monkey
#monkey.patch_dns()

url_list = []
for i in range(100):
    url_list.append('https://github.com/gevent/gevent/blob/master/src/gevent/monkey.py?id=%s' % i)

thread_count = 20
test_count = 1

def get(url):
    try:
        #data = urllib2.urlopen(url).read()
        data = requests.get(url, timeout=10
 
).content
        #data = grequests.map([grequests.get(url)])[0].content
        #print('%d bytes received from %s.' % (len(data), url))
    except BaseException:
        pass
        #print('-1 bytes received from %s.' % url)


def cusmer(q):
    while not q.empty():
        url = q.get()
        get(url)


class
 
 GT(gevent.Greenlet):
    def __init__(self, q):
        gevent.Greenlet.__init__(self)
        self.q = q

    def _run(self):
        while not self.q.empty():
            url = self.q.get()
            get(url)


def test():
    glist = []
    for i in url_list:
        glist.append(gevent.spawn(get, i))
    gevent.joinall(glist)


def test1():
    ts = []
    q = Queue()

    for i in url_list:
        q.put(i)
    for i in range(thread_count):
        ts.append( threading.Thread(target=cusmer, args=(q,)) )
    for i in ts:
        i.start()
    for i in ts:
        i.join()


def test2():
    import grequests
    for i in grequests.imap([grequests.get(i,timeout=10) for i in url_list], size=thread_count):
        try:
            len(i.content)
        except BaseException:
            pass

def test3():
    glist = []
    q = Queue()
    for i in url_list:
        q.put(i)
    for i in range(thread_count):
        glist.append(gevent.spawn(cusmer, q))
    gevent.joinall(glist)


def test4():
    ts = []
    q = Queue()
    for i in url_list:
        q.put(i)
    for i in range(thread_count):
        ts.append(GT(q) )
    for i in ts:
        i.start()
    for i in ts:
        i.join()


print "test1 thread:", timeit("test1()","from __main__ import *", number=test_count)
#monkey.patch_socket()
#monkey.patch_thread()
monkey.patch_select()
#monkey.patch_all()
print "test1 thread(patch):", timeit("test1()","from __main__ import *", number=test_count)
monkey.patch_all()
print "test spawn all(patch)", timeit("test()","from __main__ import *", number=test_count)
print "test2 grequests:", timeit("test2()","from __main__ import *", number=test_count)
print "test3 gevent.spawn", timeit("test3()","from __main__ import *", number=test_count)
print "test4 gevent.Greenlet", timeit("test4()","from __main__ import *", number=test_count)

test1 thread: 9.75339603424
test1 thread(patch): 2.32443594933
test spawn all(patch): 2.04020094872
test2 grequests: 2.95118093491
test3 gevent.spawn: 2.9419798851
test4 gevent.Greenlet: 3.03724193573

測試執行緒的時候, 首次 9s 多, 打補丁之後, 2秒多.
主要的補丁包郵 patch_socket, patch_thread, patch_select
一般多執行緒時間: 7-10s
patch_socket: 7-10s
patch_thread: 速度非常非常慢
patch_socket + patch_thread: 速度非常非常慢
patch_select: 1.5-2s
patch_select + patch_socket: 1.5-2s
patch_select + patch_thread: 31s
patch_select + patch_socket + patch_thread: 2-3s
patch_all: 2-3s
從速度上來看, patch_select 是最快的, patch_thread 後話費時間稍微有些長.

總結: 在 python2 已有程式碼基礎上實現協程, 最簡單最有效最快速的辦法: 使用 gevent.monkey

from gevent import monkey; monkey.patch_all();
# 或者 monkey.patch_select();