Multiprocessing In Following Python Code Does Not Work

I'm trying to increase the execution time of my python program by using some multiprocessing. Suppose I have this sample code: def foo(q,x,y): .... q.put(result) def par

Solution 1:

The question is short on specifics, but this works for me... I modified your use of list, since that appears to destroy python's list method (although as you say, the code still executes):

from multiprocessing import Process, Queue
import time

deffoo1(queue, procid, arg1, arg2):
    # Measure execution time and return the total time in the queueprint"%s got arg1=%s, arg2=%s " % (procid, arg1, arg2)
    start = time.time()
    ii = arg1
    while (ii > 0):
        ii = ii - 1
        time.sleep(0.01)
    # return the output of the call through the Queue
    queue.put((time.time() - start)*arg2)

defparallel_function(x):
    q1 = Queue()
    q2 = Queue()

    p1 = Process(target=foo1, args=[q1, 'Proc1', x, 1])
    p2 = Process(target=foo1, args=[q2, 'Proc2', x, 2])

    p1.start(); p2.start()
    p1.join(); p2.join()
    # Get return values from each Queue
    z = max(q1.get(), q2.get())
    return z

deffunction(_list):
    for ii in _list:
        print"FUNCTION RESULT input=%s, result=%s" % (ii, 
            parallel_function(ii))



function([100,120,130,140,150])

Output:

Proc1 got arg1=100, arg2=1 
Proc2 got arg1=100, arg2=2FUNCTIONRESULT input=100, result=2.01133012772
Proc1 got arg1=120, arg2=1 
Proc2 got arg1=120, arg2=2FUNCTIONRESULT input=120, result=2.4130563736
Proc1 got arg1=130, arg2=1 
Proc2 got arg1=130, arg2=2FUNCTIONRESULT input=130, result=2.61448001862
Proc1 got arg1=140, arg2=1 
Proc2 got arg1=140, arg2=2FUNCTIONRESULT input=140, result=2.81632232666
Proc1 got arg1=150, arg2=1 
Proc2 got arg1=150, arg2=2FUNCTIONRESULT input=150, result=3.01693964005