How to check memory utilization by a process in Linux

PS service

In Linux, process memory utilization is measured by two values, VSZ and RSS (both measured in bytes).

RSS stands for Resident Set Size and shows how much RAM is utilized at the time the command is output.
It also should be noted that it shows the entire stack of physically allocated memory.

VSZ - Virtual Memory Size. The list of processes sorted by these parameters can be viewed by using the command: For RSS (Resident Set Size): 

ps -aux --sort -rss

For VSZ (Virtual Memory Size): 

ps -aux --sort -vsz

Depending on the command that has been input, output results will be displayed in the order of priority by the percentage of RAM used by the process (RSS) or the amount of virtual memory (VSZ) used by the process in the descending order. 

$ ps -aux --sort -rss
USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
user      30799 51.2  8.1 2733764 285136 ?      Rl   09:25   5:30 /usr/lib/chromium-browser/chromium-browser --ppapi-flash-path=/usr/lib/pepperflashplugin-nonfree/libpepflashplayer.so --ppap
user       2800  0.1  6.6 9972812 234184 ?      Sl   окт31   1:26 /usr/bin/plasmashell --shut-up
user      31308  2.4  5.3 1767496 188672 ?      Sl   09:26   0:13 /usr/lib/chromium-browser/chromium-browser --type=renderer --enable-pinch --field-trial-handle=7228759356551874141,180166971
user      31011  3.9  5.3 1793296 186812 ?      Sl   09:25   0:25 /usr/lib/chromium-browser/chromium-browser --type=renderer --enable-pinch --field-trial-handle=7228759356551874141,180166971
user      31369  5.5  4.8 1378568 171328 ?      Sl   09:28   0:23 /usr/lib/libreoffice/program/soffice.bin --writer --splash-pipe=5
user      14442 12.1  4.2 1050808 150148 ?      Sl   01:19  60:04 /usr/lib/x86_64-linux-gnu/libexec/kscreenlocker_greet --graceTime 5000 --ksldfd 26
user      31111  0.9  3.8 1708496 134564 ?      Sl   09:25   0:06 /usr/lib/chromium-browser/chromium-browser --type=renderer --enable-pinch --field-trial-handle=7228759356551874141,180166971
user       1225  0.0  3.7 3639148 132092 ?      Sl   окт31   1:00 /usr/bin/plasmashell --shut-up
user      31078  0.6  3.7 1724480 130724 ?      Sl   09:25   0:03 /usr/lib/chromium-browser/chromium-browser --type=renderer --enable-pinch --field-trial-handle=7228759356551874141,180166971
user      30986  0.7  3.3 1717860 117660 ?      Sl   09:25   0:04 /usr/lib/chromium-browser/chromium-browser --type=renderer --enable-pinch --field-trial-handle=7228759356551874141,180166971
user       1216  1.7  3.2 3271220 113736 ?      Sl   окт31  20:36 kwin_x11

Important columns are:

  • USER     The user on whose behalf the process is running
  • PID         Process ID
  • RSS      The physical memory used by the process
  • VSZ      Virtual memory

It follows from the example that most of the memory (RSS) is used by the chromium browser.