多线程的鸡肋

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from contextlib import contextmanager
import time

##  因为GIL锁的原因，多线程并没有多少用
## 不适合计算密集型
@contextmanager
def _cost_time():
    start_time = time.time()
    print('start time : ' + time.strftime("%Y-%m-%d %H:%M:%S", time.localtime()))
    yield
    end_time = time.time()
    seconds = end_time - start_time
    m, s = divmod(seconds, 60)
    h, m = divmod(m, 60)
    print('end time : ' + time.strftime("%Y-%m-%d %H:%M:%S", time.localtime()))
    print('time cost  %d:%02d:%02d ' % (h, m, s))


def decrement(n):
    while n > 0:
        n -= 1

# Single thread

with _cost_time():
    decrement(100000000)

#
import threading
with _cost_time():
    t1 = threading.Thread(target=decrement,args=[50000000])
    t2 = threading.Thread(target=decrement,args=[50000000])
    t1.start()
    t2.start()
    t1.join()
    t2.join()

修改一下

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import time

##  因为GIL锁的原因，多线程并没有多少用
## 不适合计算密集型



def _cost_time(func):
    def warpper(*args,**kw):
        start_time = time.time()
        print('start time : ' + time.strftime("%Y-%m-%d %H:%M:%S", time.localtime()))
        func(*args,**kw)
        end_time = time.time()
        seconds = end_time - start_time
        m, s = divmod(seconds, 60)
        h, m = divmod(m, 60)
        print('end time : ' + time.strftime("%Y-%m-%d %H:%M:%S", time.localtime()))
        print('time cost  %d:%02d:%02d ' % (h, m, s))
    return warpper

@_cost_time
def decrement(n):
    while n > 0:
        n -= 1

# Single thread
decrement(100000000)

# Multithreading
import threading
t1 = threading.Thread(target=decrement,args=[50000000])
t2 = threading.Thread(target=decrement,args=[50000000])
t1.start()
t2.start()
t1.join()
t2.join()