Log the memory usage of a process in Linux

Create log_memory_usage.py with following contents :

#! /usr/bin/python3

import json, psutil, datetime, sys, time

f = open('memory_usage_'+sys.argv[1]+'.log', 'a')

while True:
  txt=json.dumps((datetime.datetime.now().isoformat(),psutil.Process(int(sys.argv[1])).memory_info()._asdict()))+"\n"
  f.write(txt)
  f.flush()
  time.sleep(60)

Make it executable :

chmod +x log_memory_usage.py

Usage :

./log_memory_usage.py PID

By default it logs the memory usage info every 60 seconds in a file named memory_usage_PID.log in the same folder, if you want, you can change time.sleep(60) in the code to suit your needs.