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python多进程使用multiprocessing创建线程池进程间通讯进程同步共享内存

admin 11月 13, 2020 0

multiprocessing

from multiprocessing import Process

def run_process(name):
    print("Process %s Running" %(os.getpid()))

p = Process(target=run_process, args=(str(i), )
p.start()
p.join()

使用multiprocessing创建线程池

from multiprocessing import Pool

def run_task(name):
    print("Process %s Running" %(os.getpid()))

p = Pool(processes=3)

for i in range(5):
    p.apply_async(run_task, args=(i, )) 
    
p.close() # 先close，然后再join
p.join()

进程间通讯

from multiprocessing import Queue

def proc_write(q, urls):
    for url in urls:
        q.put(url)
        time.sleep(3)

def proc_read(q):
    while True:
        url = q.get(True)
        print(url)
    
q = Queue()
p_write1 = Process(target=proc_write, args=(q, urls1))
p_write2 = Process(target=proc_write, args=(q, urls2))
p_read = Process(target=proc_read, args=(q))

p_write1.start()
p_write2.start()
p_read.start()

p_write1.join()
p_write2.join()
p_read.terminate()

进程同步

from multiprocessing import Process, Lock

def f(l, i):
    l.acquire()
    try:
        print("hello world", i)
    finally:
        l.release()

if __name__ == "__main__":
    lock = Lock()

    for num in range(10):
        Process(target=f, args=(lock, num)).start()

共享内存

from multiprocessing import Process, Value, Array
def f(n, a):
    n.value = 3.1415926
    for i in range(len(a)):
        a[i] = -a[i]

if __name__ == "__main__":
    num = Value('d', 0.1)
    arr = Array('i', range(10))

    p = Process(target=f, args=(num, arr))
    p.start()
    p.join()

    print(num.value)
    print(arr[:])