How to get the max memory usage of a program using psutil in Python

Question

I am using the following code to get the max memory usage of the program.

    import os, subprocess , psutil
    def mem(cmd):
        try:
            with          


        

Answer 1

The problem here is that psutils takes a quick snapshot from the /proc filesystem, as you can see in the source.

When you run your hello world example, in some cases it finishes before python gets a chance to read the values from /proc.

Once the process is finished, it effectively no longer consumes any ram. You can confirm this with an strace.

open("/proc/13420/statm", O_RDONLY)     = 3
read(3, "0 0 0 0 0 0 0\n", 1024)        = 14

If you modify your example to use something like sleep, you'll notice that psutils consistently gives memory usage back.

#include 
#include 

int main()
{
  std::cout << "Hello World.. sleeping!";
  sleep(3);
}

Output of your python script...

a.out
meminfo(rss=286720, vms=12931072)

One simple way to accomplish what you are trying to do, is by using the /usr/bin/time command, which on most platforms will give you the average total memory usage of the process you launch OR use valgrind as J.F Sebastian suggests... whom posted as I was researching and testing my answer ;)

Hello World.. sleeping!0.00user 0.00system 0:03.00elapsed 0%CPU     
(0avgtext+0avgdata 1144maxresident)k
0inputs+0outputs (0major+348minor)pagefaults 0swaps