How do I measure the RAM usage of desktop environments?

Question

I would like to measure the RAM usage of several desktop environments (including Cinnamon, GNOME, KDE, LXDE, LXQt, MATE and Xfce) running on my Sabayon machine. I would prefer a command-line way of checking RAM usage, if possible. I have tried using this ps_mem.py script (by running python ps_mem.py -p Cinnamon for Cinnamon, for example) but unfortunately it requires PIDs for programs and will not simply accept the name of the DE and I'm not sure which programs belong to my DE and which do not.

Answer 1

You can put together a command that parses free to tell you how much free memory you have:

free -h | awk {'print $3'} | head -3 | tail -1
1.8G

Run the bash script every half second to keep a record of your memory usage:

while true; do free | awk {'print $3'} | head -3 | tail -1 >> free.dat; sleep 0.5; done

For each environment you want to test, put that script in the list of automatically run programs (e.g., for Fluxbox it goes in ~/.fluxbox/startup). You can readily view your plots by running gnuplot and calling

gnuplot> plot 'free.fluxbox.dat' using 1 with impulses

Now, the hard part is your apples to apples comparison. If you want to see how memory usage looks after opening lots of programs, you can put this script in yet another script, followed by subsequent calls to libreoffice, firefox and gnome-system-monitor, or whatever list you like. Alternatively, you could just open them manually, but that really doesn't seem like a tenable approach to honestly comparing environments.