Total memory used by Python process?

Question

Is there a way for a Python program to determine how much memory it's currently using? I've seen discussions about memory usage for a single object, but what I need is total memory usage for the process, so that I can determine when it's necessary to start discarding cached data.

Answer 1

Here is a useful solution that works for various operating systems, including Linux, Windows, etc.:

import os, psutil process = psutil.Process(os.getpid()) print(process.memory_info().rss)  # in bytes  

Notes:

• do pip install psutil if it is not installed yet

• handy one-liner if you quickly want to know how many MB your process takes:

  import os, psutil; print(psutil.Process(os.getpid()).memory_info().rss / 1024 ** 2) 

• with Python 2.7 and psutil 5.6.3, it was process.memory_info()[0] instead (there was a change in the API later).

Answer 2

For Unix based systems (Linux, Mac OS X, Solaris), you can use the getrusage() function from the standard library module resource. The resulting object has the attribute ru_maxrss, which gives the peak memory usage for the calling process:

>>> resource.getrusage(resource.RUSAGE_SELF).ru_maxrss 2656  # peak memory usage (kilobytes on Linux, bytes on OS X) 

The Python docs don't make note of the units. Refer to your specific system's man getrusage.2 page to check the unit for the value. On Ubuntu 18.04, the unit is noted as kilobytes. On Mac OS X, it's bytes.

The getrusage() function can also be given resource.RUSAGE_CHILDREN to get the usage for child processes, and (on some systems) resource.RUSAGE_BOTH for total (self and child) process usage.

If you care only about Linux, you can alternatively read the /proc/self/status or /proc/self/statm file as described in other answers for this question and this one too.