memory-usage-wait3.py

"""
Find maximum memory consumed by a process specified at the command-line.

Usage:

    $ python memory-usage-wait3.py cmd arg1 arg2
"""
import os
import sys
import threading
from subprocess import Popen
import psutil # $ pip install psutil

def report_memory(pid):
    p = psutil.Process(pid)
    max_rss, max_vms = -1, -1
    while True:
        try:
            rss, vms = p.memory_info()
        except psutil.NoSuchProcess:
            break
        else:
            if rss > max_rss:
                max_rss = rss
            if vms > max_vms:
                max_vms = vms
    print((max_rss//(1<<20), max_vms//(1<<20))) # MB


args = sys.argv[1:]
p = Popen(args)
t = threading.Thread(target=report_memory, args=[p.pid])
t.start()
ru = os.wait4(p.pid, 0)[2]
t.join()
print("Maximum rss %d MB" % (ru.ru_maxrss//1024,))