multiprocessing pool test, process-based and thread-based

mptest.py

# -*- coding: utf-8 -*-
# QGIS 3.x / Python 3.x

from math import sqrt, ceil
from multiprocessing import Pool, Process, Queue
from multiprocessing.pool import ThreadPool

WORKERS = 2

def worker_task(number):
    return sqrt(number ** 2)

def test1():
    data = list(range(0, 100, 10))
    print('creating pool')
    pool = Pool(WORKERS)
    print('computing')
    results = pool.map(worker_task, data)
    print('result', results)
    print('closing pool')
    pool.close()
    print('done')

def test2():
    data = list(range(0, 100, 10))
    print('creating pool')
    with Pool(WORKERS) as pool:
        print('computing')
        results = pool.map(worker_task, data)
        print('result', results)
        print('closing pool')
    print('done')

def worker_wrapper(queue, data):
    queue.put([worker_task(number) for number in data])

def test3():
    data = list(range(0, 100, 10))
    interval = ceil(len(data) / WORKERS)
    print('creating pool')
    pool = []
    for index in range(WORKERS):
        queue = Queue()
        process = Process(
            target = worker_wrapper,
            args = (queue, data[index*interval:(index+1)*interval])
        )
        process.start()
        pool.append({'process': process, 'queue': queue})
    print('computing')
    results = [number for worker in pool for number in worker['queue'].get()]
    print('result', results)
    print('closing pool')
    for worker in pool:
        worker['process'].join()
    print('done')

def test4():
    data = list(range(0, 100, 10))
    print('creating pool')
    pool = ThreadPool(WORKERS)
    print('computing')
    results = pool.map(worker_task, data)
    print('result', results)
    print('closing pool')
    pool.close()
    print('done')

def test5():
    data = list(range(0, 100, 10))
    print('creating pool')
    with ThreadPool(WORKERS) as pool:
        print('computing')
        results = pool.map(worker_task, data)
        print('result', results)
        print('closing pool')
    print('done')