Parallel figure generation in python

Parallel_images.py

#!/usr/bin/env python
# coding: utf-8
#
# $ time ./Parallel_images.py
# Use 8 processes
# 107.249u 2.444s 0:17.10 641.4%	0+0k 0+0io 1056pf+0w
#

import os
import numpy as np
import multiprocessing
import matplotlib.pyplot as plt

import matplotlib as mpl
mpl.use('Agg')

N = 1000

def generate_one_figure(it=1):
    fig, ax = plt.subplots(ncols=1, nrows=1, figsize=(10,5), dpi=80)
    x = np.linspace(-np.pi, np.pi, N)
    ax.grid(1)
    ax.plot(x, np.sin(x))
    ax.plot(x[it], np.sin(x[it]),'r+', markersize=12)
    ax.set_title("%3d" % it)
    fig.savefig(os.path.abspath(os.path.sep.join([".","dummy_images","image_%0.4d.png" % it])))
    plt.close(fig)
    return None

print('Use %i processes' % multiprocessing.cpu_count() ) 
with multiprocessing.Pool() as pool:
    pool.map(generate_one_figure, np.arange(0,N))