进程、线程

multiprocessing

from multiprocessing import Pool
import os,time,random

def long_time_task(name):
    print('run task %s (%s)...'% (name,os.getpid()))
    start = time.time()
    time.sleep(random.random()*3)
    end = time.time()
    print('task %s runs %0.2f seconds'% (name,(end-start)))

if __name__ =='__main__':
    print('parent process %s '% os.getpid())
    p = Pool(4)
    for i in range(5):
        p.apply_async(long_time_task,args=(i,))
    print('waitng for all subprocesses done...')
    p.close()
    p.join()
    print('all subprocesses done')

 threading

import time,threading

def loop():
    print('thread %s is running...'% threading.current_thread().name)
    n = 0
    while n<5:
        n += 1
        print('thread %s >>>%s'%(threading.current_thread().name,n))
        time.sleep(1)
    print('thread %s ended'% threading.current_thread().name)
print('thread %s is running...'% threading.current_thread().name)
t = threading.Thread(target=loop,name='loopThread')
t.start()
t.join()
print('thread %s ended'% threading.current_thread().name)

 lock

import time,threading
#假定这是银行存款
balance = 0

def change_it(n):
    #先存后取，结果应是0
    global balance
    balance += n
    balance -= n

# def run_thread(n):
#     for i in range(100000):
#         change_it(n)
#
lock = threading.Lock()
def run_thread(n):
    for i in range(100000):
        #先要获取锁
        lock.acquire()
        try:
            #可以放心改
            change_it(n)
        finally:
            #改完了一定要释放锁
            lock.release()

#
t1 = threading.Thread(target=run_thread,args=(5,))
t2 = threading.Thread(target=run_thread,args=(8,))
t1.start()
t2.start()
t1.join()
t2.join()
print(balance)

 ThreadLocal

import threading

#创建全局ThreadLocal对象：
local_school = threading.local()

def process_student():
    #获取当前线程关联的student
    std = local_school.student
    print('hello %s (in %s)'%(std,threading.current_thread().name))

def process_thread(val):
    #绑定ThreadLocal的student
    local_school.student = val
    process_student()

t1 = threading.Thread(target=process_thread,args=('alice',),name='Thread-A')
t2 = threading.Thread(target=process_thread,args=('bob',),name='Thread-B')
t1.start()
t2.start()
t1.join()
t2.join()