5

我想同时执行以下两个功能。

from multiprocessing import Process
import os
import datetime

def func_1(title):
    now = datetime.datetime.now()
    print "hello, world"
    print "Current second: %d" % now.second
    print "Current microsecond: %d" % now.microsecond

def func_2(name):
    func_1('function func_2')
    now = datetime.datetime.now()
    print "Bye, world"
    print "Current second: %d" % now.second
    print "Current microsecond: %d" % now.microsecond

if __name__ == '__main__':
    p = Process(target=func_2, args=('bob',))
    p.start()
    p.join()

而且我得到了微秒的差异。有没有办法同时执行两者？任何帮助，将不胜感激。

4

4 回答 4

5

这是（1）通常是不可能的（“精确”部分）和（2）不是 Python 擅长的。如果您真的需要微秒级的执行精度，请使用 C 或 ASM，但比COpython 的答案更接近的方法是忙于在两个不同的进程中等待商定的开始时间：

from multiprocessing import Process
import os
import datetime
from time import time

def func_1(title):
    now = datetime.datetime.now()
    print "hello, world"
    print "Current second: %d" % now.second
    print "Current microsecond: %d" % now.microsecond

def func_2(name):
    now = datetime.datetime.now()
    print "Bye, world"
    print "Current second: %d" % now.second
    print "Current microsecond: %d" % now.microsecond

def start_f1(name):
    while time() < start_time: pass
    func_1(name)

def start_f2(name):
    while time() < start_time: pass
    func_2(name)        

if __name__ == '__main__':
    procs = []
    procs.append(Process(target=start_f2, args=('bob',)))
    procs.append(Process(target=start_f1, args=('sir',)))
    start_time = time() + 10
    map(lambda x: x.start(), procs)
    map(lambda x: x.join(), procs)
于 2012-11-20T14:32:05.470 回答
5

在编写以下代码的计算机上，此代码始终打印出相同的时间戳：

#! /usr/bin/env python3
from multiprocessing import Barrier, Lock, Process
from time import time
from datetime import datetime

def main():
    synchronizer = Barrier(2)
    serializer = Lock()
    Process(target=test, args=(synchronizer, serializer)).start()
    Process(target=test, args=(synchronizer, serializer)).start()

def test(synchronizer, serializer):
    synchronizer.wait()
    now = time()
    with serializer:
        print(datetime.fromtimestamp(now))

if __name__ == '__main__':
    main()
于 2012-11-20T17:53:34.637 回答
2

我不确定这是否会同时执行，但我认为它会让你更接近。

from multiprocessing import Process
import os
import datetime


def func_1(title):
    now = datetime.datetime.now()
    print "hello, world"
    print "Current second: %d" % now.second
    print "Current microsecond: %d" % now.microsecond


def func_2(name):
    now = datetime.datetime.now()
    print "Bye, world"
    print "Current second: %d" % now.second
    print "Current microsecond: %d" % now.microsecond


if __name__ == '__main__':
    procs = []
    procs.append(Process(target=func_2, args=('bob',)))
    procs.append(Process(target=func_1, args=('sir',)))
    map(lambda x: x.start(), procs)
    map(lambda x: x.join(), procs)
于 2012-11-20T14:21:00.487 回答
1

CPython本质上是单线程的（谷歌“全局解释器锁”）。为了获得理论上的机会，您需要一个多核处理器，但即便如此，只有在非常低级别运行的操作系统才能做到这一点，即使那样您也需要特殊的硬件。您所要求的是，在任何实际意义上， 不可能的。

于 2012-11-20T15:57:37.797 回答