python多进程Pool.map代码执行时报错

Question

我的机器是win7 64位，python版本2.7，想写一段代码，比较一下本机上多进程和多线程的执行效率，在跑并行执行20次1-10万的乘法运算的代码时执行失败，请帮忙看应该怎么修改：

import multiprocessing
from multiprocessing import Pool
from datetime import datetime

def cal_sum_not_so_big():
    i=1
    sum=0
    while i <= 100000000:
        sum+=i
        i+=1
    return 'sum is %s ' % sum
    
    
cal_a=cal_multi_not_so_big


def run_and_log(function,name,*options): 
    start=datetime.now()
    print '%s instance %s starts at %s' % (function,name,start)
    function(*options)
    end=datetime.now()
    print '%s instance %s ends at %s,cost %s' % (function,name,start,end-start)
    

def scen2_full_proc(func):
    cpu_number=multiprocessing.cpu_count()
    pool=Pool(cpu_number)

    opt1=[]
    i=1
    while i <=20:
        opt1.append((func,i,))
        i+=1

    start=datetime.now()
    print 'full proc test start at %s' % start
    pool.map(run_and_log,opt1)
    end=datetime.now()
    print 'full proc test end at %s ,cost %s' % (end,end-start,)


if __name__ == "__main__":
    multiprocessing.freeze_support()
    scen2_full_proc(cal_a)

报错：
Traceback (most recent call last):
File "E:/dev/python/trackRF/threadpools/multicompare.py", line 93, in <module>

scen2_full_proc(cal_a)

File "E:/dev/python/trackRF/threadpools/multicompare.py", line 75, in scen2_full_proc

pool.map(run_and_log,opt1)

File "C:\Python27\lib\multiprocessing\pool.py", line 251, in map

return self.map_async(func, iterable, chunksize).get()

File "C:\Python27\lib\multiprocessing\pool.py", line 558, in get

raise self._value

TypeError: run_and_log() takes at least 2 arguments (1 given)

Answer 1

map函数只支持一个参数的函数，需要改造run_and_log函数只接受一个参数，比如：

def run_and_log((function,name)): 
    start=datetime.now()
    print '%s instance %s starts at %s' % (function,name,start)
    function()
    end=datetime.now()
    print '%s instance %s ends at %s,cost %s' % (function,name,start,end-start)