Multiplicacion de Matriz en Paralelo Python

#!/usr/bin/python
import time
import os
from random import randint
from threading import Thread

inicio = time.time()
n = 3
# PARA HACER Numeros aleatorios
# matrix = [[randint(0,3) for fila in range(n)] for col in range(n)]
matrix1 = [[1, 2, 3], [3, 4, 5], [3, 2, 1]]
matrix2 = [[2, 3, 4], [5, 5, 5], [1, 1, 1]]
matrix3 = [[0 for fila in range(n)] for col in range(n)]


class Hilo(Thread):
    def __init__(self, matrix1, matrix2, matrix3, n, x, y):
        Thread.__init__(self)
        self.matrix1 = matrix1
        self.matrix2 = matrix2
        self.matrix3 = matrix3
        self.n = n
        self.x = x
        self.y = y

    def run(self):
        global x, y
        for i in range(n):
            matrix3[x][y] += matrix1[self.x][i]*matrix2[i][self.y]

def main():
    os.system("clear")
    print "\n", matrix1[0], "\n", matrix1[1], "\n", matrix1[2]
    print "\n", matrix2[0], "\n", matrix2[1], "\n", matrix2[2]
    matrix3 = multiplicar(matrix1,matrix2,n)
    print "\n", matrix3[0], "\n", matrix3[1], "\n", matrix3[2]
    fin = time.time()
    tiempo = fin - inicio
    print "\nTiempo de ejecucion: ", tiempo

def multiplicar(matrix1, matrix2, n):
    global x, y
    hilo = list()

    for x in range(n):
        for y in range(n):
            hilo.append(Hilo(matrix1, matrix2, matrix3, n, x, y))
            hilo[-1].start()

    for h in hilo:
        h.join()

    return matrix3

main()