Total memory used by Python process?

Solution 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

With Python 2.7 and psutil 5.6.3, the last line should be

print(process.memory_info()[0])

instead (there was a change in the API later).

Note:

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)

Solution 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.

Solution 3:

On Windows, you can use WMI (home page, cheeseshop):

def memory():
    import os
    from wmi import WMI
    w = WMI('.')
    result = w.query("SELECT WorkingSet FROM Win32_PerfRawData_PerfProc_Process WHERE IDProcess=%d" % os.getpid())
    return int(result[0].WorkingSet)

On Linux (from python cookbook http://code.activestate.com/recipes/286222/:

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

_scale = {'kB': 1024.0, 'mB': 1024.0*1024.0, 'KB': 1024.0, 'MB': 1024.0*1024.0}

def _VmB(VmKey):
    '''Private.'''
    global _proc_status, _scale
     # get pseudo file  /proc/<pid>/status
    try:
        t = open(_proc_status)
        v = t.read()
        t.close()
    except:
        return 0.0  # non-Linux?
     # get VmKey line e.g. 'VmRSS:  9999  kB\n ...'
    i = v.index(VmKey)
    v = v[i:].split(None, 3)  # whitespace
    if len(v) < 3:
        return 0.0  # invalid format?
     # convert Vm value to bytes
    return float(v[1]) * _scale[v[2]]

def memory(since=0.0):
    '''Return memory usage in bytes.'''
    return _VmB('VmSize:') - since

def resident(since=0.0):
    '''Return resident memory usage in bytes.'''
    return _VmB('VmRSS:') - since

def stacksize(since=0.0):
    '''Return stack size in bytes.'''
    return _VmB('VmStk:') - since

Solution 4:

On unix, you can use the ps tool to monitor it:

$ ps u -p 1347 | awk '{sum=sum+$6}; END {print sum/1024}'

where 1347 is some process id. Also, the result is in MB.

Solution 5:

Current memory usage of the current process on Linux, for Python 2, Python 3, and pypy, without any imports:

def getCurrentMemoryUsage():
    ''' Memory usage in kB '''

    with open('/proc/self/status') as f:
        memusage = f.read().split('VmRSS:')[1].split('\n')[0][:-3]

    return int(memusage.strip())

It reads the status file of the current process, takes everything after VmRSS:, then takes everything before the first newline (isolating the value of VmRSS), and finally cuts off the last 3 bytes which are a space and the unit (kB).
To return, it strips any whitespace and returns it as a number.

Tested on Linux 4.4 and 4.9, but even an early Linux version should work: looking in man proc and searching for the info on the /proc/$PID/status file, it mentions minimum versions for some fields (like Linux 2.6.10 for "VmPTE"), but the "VmRSS" field (which I use here) has no such mention. Therefore I assume it has been in there since an early version.