Python total memory used

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

Heapy (and friends) may be what you're looking for.

Also, caches typically have a fixed upper limit on their size to solve the sort of problem you're talking about. For instance, check out this LRU cache decorator.

Answer 2

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.

Answer 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