在Python中使用usleep

Question

我在Python 2.7中搜索usleep（）函数。

有没有人知道它是否存在，也许与另一个函数名？

Answer 1

由于usleep通常意味着希望延迟对于x微秒执行，则必须通过1000000

import time 
time.sleep(seconds/1000000.0) 

time.sleep()只需几秒钟作为参数划分秒值。

http://docs.python.org/library/time.html#time.sleep

Answer 2

from time import sleep 
sleep(seconds) 

More info。

Answer 3

from time import sleep 
sleep(0.1) #sleep during 100ms 

Answer 4

import time 
usleep = lambda x: time.sleep(x/1000000.0) 

usleep(100) #sleep during 100μs 

Answer 5

非常非常小心time.sleep。我被python3使用time.sleep烧了，因为它是非单调的。如果挂钟倒退，time.sleep呼叫将不会完成，直到挂钟赶上睡眠按计划前进的位置。我还没有发现蟒蛇单调睡眠。

相反，我建议Event.wait，像这样：

def call_repeatedly(interval, func, *args, **kwargs): 
    stopped = Event() 
    def loop(): 
     while not stopped.wait(interval): # the first call is in `interval` secs 
      try: 
       func(*args) 
      except Exception as e: 
       logger.error(e); 
       if kwargs.get('exception'): 
        kwargs.get('exception')(e) # SEND exception to the specified function if there is one. 
       else: 
        raise Exception(e) 
    Thread(target=loop).start() 
    return stopped.set 

http://pastebin.com/0rZdY8gB

Answer 6

这个怎么样：

import time 
def usleep(delay): 
    mdelay = delay /1000 
    now = time.time() 
    while now + mdelay > time.time(): 
     pass 

Answer 7

的蟒蛇是交替睡眠功能。

注意：由于GIL锁，不应该用于多线程，但对于多个子进程来说它很好。与time.sleep（）相同

我正在将C函数封装到Python中。我正在使用C库的nanosleep（）函数，这会暂停运行那么多时间的线程。这不是一个忙碌的等待类型的延迟，它使用很多CPU来评估一些数学。代码如下。 CWrapper说，把所有的文件放在一个文件夹中。

C_functions.h

#include <time.h> 
int c_sleep_msec(long milliseconds); 
int c_sleep_nsec(long nanoseconds); 

C_functions.c

#include "C_functions.h" 
int c_sleep_msec(long milliseconds) { 
    struct timespec req; 
    //struct timespec rem; 
    if(milliseconds > 999) { 
     req.tv_sec = (int)(milliseconds/1000); /* Must be Non-Negative */ 
     req.tv_nsec = (milliseconds - ((long)req.tv_sec * 1000)) * 1000000; /* Must be in range of 0 to 999999999 */ 
    } 
    else { 
     req.tv_sec = 0;       /* Must be Non-Negative */ 
     req.tv_nsec = milliseconds * 1000000; /* Must be in range of 0 to 999999999 */ 
    } 
    //rem = NULL; 
    return nanosleep(&req , NULL); 
} 
//------------------------------------------------------ 
int c_sleep_nsec(long nanoseconds) { 
    struct timespec req; 
    //struct timespec rem; 
    if (nanoseconds > 999999999) { 
     req.tv_sec = (int)(nanoseconds/1000000000); 
     req.tv_nsec = (nanoseconds - ((long)req.tv_sec * 1000000000)); 
    } 
    else { 
     req.tv_sec = 0; 
     req.tv_nsec = nanoseconds; 
    } 
    //rem = NULL; 
    return nanosleep(&req , NULL); 
} 

还可以创建使用相同了nanosleep（）

CWrapper.pyx

cdef extern from "C_functions.h": 
    int c_sleep_msec(long milliseconds) 
    int c_sleep_nsec(long nanoseconds) 

def sleep_msec(milliseconds): 
    return c_sleep_msec(milliseconds) 

def sleep_nsec(nanoseconds): 
    return c_sleep_nsec(nanoseconds) 

微秒的功能

setup.py

from distutils.core import setup 
from distutils.extension import Extension 
from Pyrex.Distutils import build_ext 

setup(
    name = "CWrapper", 
    ext_modules=[ Extension("CWrapper", ["CWrapper.pyx", "C_functions.c"]) ], 
    cmdclass = {'build_ext': build_ext} 
) 

安装python-pyrex。然后在linux终端上运行

python setup.py build_ext -i 

它会创建CWrapper.c，build和CWrapper.so文件。使用CWrapper.so只要你想要的，只需在python中导入。

注意：分别为Raspberry Pi编译。

现在，测试函数

Test_sleep.py

import serial 
from multiprocessing import Process 
import time 
import CWrapper 


class TestSleep: 
    def __init__(self): 
     self.delay_sec = 0.00000100 
     self.delay_msec = 30 
     self.delay_nsec = 1000 #200000000 
     self.start_time = time.time() 

     self.process_1 = Process(name="process_1", target=self.process_1_task, args=("process_1",)) 
     self.process_1.daemon = True 
     self.process_1.start() 

     self.process_2 = Process(name="process_2", target=self.process_1_task, args=("process_2",)) 
     self.process_2.daemon = True 
     self.process_2.start() 

     self.process_3 = Process(name="process_3", target=self.process_1_task, args=("process_3",)) 
     self.process_3.daemon = True 
     self.process_3.start() 

    def process_1_task(self, process_name): 
     start = self.start_time 
     delay_msec = self.delay_msec 
     delay_sec = self.delay_sec 
     delay_nsec = self.delay_nsec 

     t1 = start 
     for i in range(1, 81): 
      status = CWrapper.sleep_msec(delay_msec) 
      # status = CWrapper.sleep_nsec(delay_nsec) 
      #status = time.sleep(delay_sec) 
      t2 = time.time() 
      elapsed_time = t2 - t1 
      t1 = t2 
      print process_name, i, "status:", status, "Elapsed-time:", elapsed_time 


if __name__ == '__main__': 
    test = TestSleep() 
    # for i in range(1,10000): 
    #  print "main thread", i 
     # time.sleep(0.1) 
    while True: # Since daemon=True, main thread should check join() or stay in loop 
     pass 

改变参数delay_sec为time.sleep（），用于delay_msec CWrapper.sleep_msec（），用于delay_nsec CWrapper.sleep_nsec（）。取消您想要在thread_1_task（）中测试的函数的注释。