Python Multiprocessing - 멀티프로세싱

www.youtube.com/watch?v=fKl2JW_qrso&t=185s

멀티쓰레딩과 거.. 의 똑같다.

키워드만 다를 뿐..

 

import time
import multiprocessing

start = time.perf_counter()

def something():
	print('sleeping..1 second)
    time.sleep(1)
    print('Done sleeping')
    
processes = []

for _ in range(10):
	p = multiprocessing.Process(target=do_something)
    p.start()
    processes.append(p)
    
for process in processes:
	process.join()

finish = time.perf_counter()

print(f'Finished in {round(finish-start, 2} second')

그리고 멀티쓰레딩에서 concurrent.futures.ThreadPoolExecutor 대신 이번엔 ProcessPoolExecutor사용하면 됨!

(정말 그렇게 간단하다)

 

import time
import concurrent.futures

start = time.perf_counter()

def something(s):
    print('sleeping..1 second)
    time.sleep(s)
    return 'done!'
    # print('Done sleeping')
    
with concurrent.futures.ProcessPoolExecutor() as executor:
    f1 = executor.submit(something, 1)
    f2 = executor.submit(something, 1)
    print(f1.result())
    print(f2.result())

finish = time.perf_counter()

print(f'Finished in {round(finish-start, 2} second')

이러면 GIL(Global Interpretation Lock)에서 벗어나서 여러 프로세스를 여러 코어에 돌릴수 있음!

as_completed 도 사용가능하고,

secs = [5, 4, 3, 2, 1]
results = [executor.submit(something, sec) for sec in secs]

for f in concurrent.futures.as_completed(results):
    print(f.result())

map도 가능하다!

results = executor.map(something, secs)