python:线程，多线程锁，多线程递归锁

Posted 2020-10-22 CanSun

#!usr/bin/env python
# -*- coding:utf-8 -*-

__author__ = "Samson"

import threading,time
def run(n):
    print("task", n)
    time.sleep(2)
    print("current thread:",threading.current_thread())#当前线程

t_obj = []#存线程实例
start_time = time.time()
for i in range(50):
    t = threading.Thread(target=run,args=("t%s" %i,))
    #t.setDaemon(True)#把当前线程设置为守护线程，必须在t.start()之前设置，作用为主线程将不会等待该子线程结束
    t.start()
    t_obj.append(t)
print("total thread:",threading.active_count())#总线程数
for t in t_obj:
    t.join()#等待线程执行完
print("%s" %(abs(start_time-time.time())))

多线程锁

#!usr/bin/env python
# -*- coding:utf-8 -*-

__author__ = "Samson"

import threading,time
def run(n):
    lock.acquire()#锁上
    global num
    num += 1
    #time.sleep(1)#会变为单线程
    lock.release()#解锁
lock = threading.Lock()#创建锁
num = 0
t_obj = []#存线程实例
for i in range(50):
    t = threading.Thread(target=run,args=("t%s" %i,))
    t.start()
    t_obj.append(t)
for t in t_obj:
    t.join()
print("%s" %num)

多线程递归锁

#!usr/bin/env python
# -*- coding:utf-8 -*-

__author__ = "Samson"

import threading,time
def run():
    lock.acquire()#锁上
    res = run1()
    res2 = run2()
    lock.release()#解锁
def run1():
    lock.acquire()#锁上
    global num
    num += 1
    lock.release()#解锁
def run2():
    lock.acquire()#锁上
    global num
    num += 1
    lock.release()#解锁
lock = threading.RLock()#创建递归锁
num = 0
for i in range(10):
    t = threading.Thread(target=run)
    t.start()
print("Now:",threading.active_count())
while threading.active_count() != 1:
    print(threading.active_count())
else:
    print("%s" %num)