Python定时器占用太多cpu

Question

当我检查任务管理器时，下面的运行有时在9小时或更长时间后无法发出警报，因为它消耗了30%或更多的CPU。如果有人能调整一下，那就太好了。

import time
import ctypes
def timer(hours):
    seconds = hours * 3600
    start = time.time()
    time.clock()
    elapsed = 0
    while elapsed < seconds:
     elapsed = time.time() - start
    elapsed = elapsed//60
    ctypes.windll.user32.MessageBoxA(0,"Done "+str(elapsed) + " Hrs",  "Done", 0)
timer(8)     

Answer 1

试试这个:

import time
import ctypes
def timer(hours):
    seconds = hours * 3600
    start = time.time()
    elapsed = 0
    while elapsed < seconds:
        # Do something once every minute.
        time.sleep(60)
        elapsed = time.time() - start
    elapsed = elapsed//60
    ctypes.windll.user32.MessageBoxA(0,"Done "+str(elapsed) + " Hrs",  "Done", 0)
timer(8)   

问题是你在循环中没有sleep()，所以循环实际上只是每秒运行数百到数千或数万次，消耗CPU。上面的代码将在重复循环之前等待1分钟。

如果你在等待计时器时不需要做任何事情，你可以完全避免循环，只使用sleep():

import time
import ctypes
def timer(hours):
    time.sleep(hours * 3600)
    ctypes.windll.user32.MessageBoxA(0,"Done "+str(hours) + " Hrs",  "Done", 0)
timer(8) 

Answer 2

这难道不会达到完全相同的效果吗?因为你在循环的时候什么也没做。

import time
import ctypes
def timer(hours):
    start = this.time()
    time.sleep(hours * 3600)
    ctypes.windll.user32.MessageBoxA(0,"Done "+str(hours) + " Hrs",  "Done", 0)