Why use threading data race will occur, but will not use gevent
- by onlytiancai
My test code is as follows, using threading, count is not 5,000,000 , so there has been data race, but using gevent, count is 5,000,000, there was no data race .
Is not gevent coroutine execution will atom "count + = 1", rather than split into a one CPU instruction to execute?
# -*- coding: utf-8 -*-
import threading
use_gevent = True
use_debug = False
cycles_count = 100*10000
if use_gevent:
from gevent import monkey
monkey.patch_thread()
count = 0
class Counter(threading.Thread):
def __init__(self, name):
self.thread_name = name
super(Counter, self).__init__(name=name)
def run(self):
global count
for i in xrange(cycles_count):
if use_debug:
print '%s:%s' % (self.thread_name, count)
count = count + 1
counters = [Counter('thread:%s' % i) for i in range(5)]
for counter in counters:
counter.start()
for counter in counters:
counter.join()
print 'count=%s' % count
