How to find running time of a thread in Python

问题:

I have a multi-threaded SMTP server. Each thread takes care of one client. I need to set a timeout value of 10 seconds on each server thread to terminate dormant or misbehaving clients.
I have used the time.time(), to find the start time and my checkpoint time and the difference gives the running time. But I believe it gives the system time and not the time this thread was running.
Is there a Thread local timer API in Python ?

   import threading
   stop = 0

   def hello():
     stop = 1

   t=threading.Timer(10,hello)
   t.start()
   while stop != 1:
      print stop
   print "stop changed"

This prints 0 (initial stop) in a loop and does not come out of the while loop.

回答1:

In the python documentation there is no mention of "thread timing". Either the clocks are process-wide or system-wide. In particular time.clock measures process time while time.time returns the system time.

In python3.3 the timings API was revised and improved but still, I can't see any timer that would return the process time taken by a single thread.

Also note that even if possible it's not at all easy to write such a timer. Timers are OS specific, so you would have to write a different version of the module for every OS. If you want to profile a specific action, just launch it without threads. When threaded the timing either it runs as expected, or it is a lot slower because of the OS, in which case you can't do nothing about it(at least, if you don't want to write a patch that "fixes" the GIL or removes it safely).

回答2:

The hello function's stop value is local, not the global one.

Add the following:

def hello():
   global stop
   stop = 1

回答3:

Python has progressed in the 6 years since this question was asked, and in version 3.3 it's introduced a tool for exactly what was being asked for here:

time.clock_gettime(time.CLOCK_THREAD_CPUTIME_ID)

Python 3.7 additionally introduced an analogous time.clock_gettime_ns.

Detailed docs are exactly where you'd expect but the feature is pretty straightforward straight out of the box.

回答4:

I am posting a sample code which can measure the running time of the thread, you can modify the code, so as to use with your function.

    import time
    import threading
    def hello():
        x = 0 
        while x < 100000000:
            pass
            x += 1
    start = time.clock()
    t = threading.Thread(target = hello, args = ())
    t.start() 
    t.join()
    end = time.clock()
    print "The time was {}".format(end - start)

On my system, it gave a time of 8.34 seconds.