Pausing a process?

Question

Is there a way to pause a process (running from an executable) so that it stops the cpu load while it's paused, and waits till it's unpaused to go on with its work? Possibly in python, or in some way accessible by python.

Answer 1

I just implemented this with signals in python something like this:

def mysignalhandler(sig, frame):
  print "Got " + str(sig)
  if sig == signal.SIGUSR1:
    do_something()

signal.signal(signal.SIGUSR1, mysignalhandler)

signal.pause()

This will pause at the last line and call do_something() when it receives the signal USR1, for example through a

kill -USR1 <pid>

command.

This will only work in UNIX though.

Answer 2

There is a (almost) native way of doing this in Python, and it's quite simple :

import time
time.sleep(5)

In this snippet, 5 is the number of seconds you want to pause your program.

Answer 3

By using psutil ( https://github.com/giampaolo/psutil ):

>>> import psutil
>>> somepid = 1023
>>> p = psutil.Process(somepid)
>>> p.suspend()
>>> p.resume()

Answer 4

you are thinking of SIGTSTP -- the same signal that happens when you push CTRL-Z. This suspends the process until it gets SIGCONT.

of course, some programs can just catch and ignore this signal, so it depends on the executable. however, if you can suspend and resume it manually, you can do it from a python program, too. use os.kill()