ksuralta ksuralta - 3 months ago 14x
Linux Question

How to measure actual memory usage of an application or process?

This question is covered here in great detail.

How do you measure the memory usage of an application or process in Linux?

From the blog article of Understanding memory usage on Linux,

is not an accurate tool to use for this intent.

is "wrong"

Depending on how you look at it,
is not reporting the real memory usage of processes. What it is really doing is showing how much real memory each process would take up if it were the only process running. Of course, a typical Linux machine has several dozen processes running at any given time, which means that the VSZ and RSS numbers reported by
are almost definitely wrong.


With ps or similar tools you will only get the amount of memory pages allocated by that process. This number is correct, but:

  • does not reflect the actual amount of memory used by the application, only the amount of memory reserved for it

  • can be misleading if pages are shared, for example by several threads or by using dynamically linked libraries

If you really want to know what amount of memory your application actually uses, you need to run it within a profiler. For example, valgrind can give you insights about the amount of memory used, and, more importantly, about possible memory leaks in your program.