How to get memory usage of an external program - python

Question

I am trying to get the memory usage of an external program within my python script. I have tried using the script http://code.activestate.com/recipes/286222/ as follows:

m0 = memory()
subprocess.call('My program')
m1 = memory(m0)
print m1

But this seems to be just giving me the memory usage of the python script rather than 'My program'. Is there a way of outputting the memory usage of the program for use within the python script?

Answer 1

If you look at the recipe you will see the line:

_proc_status = '/proc/%d/status' % os.getpid()

I suggest you replace the os.getpid() with the process id of your child process. As @Neal said, as I was typing this you need to use Popen and get the pid attribute of the returned object.

However, you have a possible race condition because you don't know at what state the child process is at, and the memory usage will vary anyway.

Answer 2

Try using Psutil

import psutil
import subprocess
import time

SLICE_IN_SECONDS = 1
p = subprocess.Popen('calling/your/program')
resultTable = []
while p.poll() == None:
  resultTable.append(psutil.get_memory_info(p.pid))
  time.sleep(SLICE_IN_SECONDS)

Answer 3

You may want to check out the psutil module: http://code.google.com/p/psutil/. The Process Management section on the homepage gives you examples of getting memory usage for a running process specified by the pid.

Do you want to spawn the process you are monitoring in your script as well? If so, you probably don't want to use subprocess.call as this will wait for the program to exit and you won't be able to monitor it while it's running. If you want to spawn the process then monitor it, you probably want to use Popen http://docs.python.org/library/subprocess.html#subprocess.Popen. This will allow you to spawn the process, get the pid, hand the pid to psutil, then monitor the memory usage.

Answer 4

I know this is an older post, but it's the only one that appears when I google this issue, so, I want to add the updated version of this:

import psutil
import humanfriendly

proc = subprocess.Popen("...Your process...")
SLICE_IN_SECONDS = 1
while proc.poll() is None:
    p = psutil.Process(proc.pid)
    mem_status = "RSS {},  VMS: {}".format(humanfriendly.format_size(p.memory_info().rss),
                humanfriendly.format_size(p.memory_info().vms))
    time.sleep(SLICE_IN_SECONDS)
    print(mem_status)

I used humanfriendly here, to make the values more readable, but it's not required.

The RSS and VMS values are on all os, and there may be other values depending on the os you're using: https://psutil.readthedocs.io/en/latest/#psutil.Process.memory_info