Memory usage in l4linux

Hello, well i 'd like to know how much memory uses each l4 application launched in my l4linux system. I'm pretty sure that there's no program for this purpose. I'm gonna write this but i don't really how to do it so if someone could give me so hints about how to start (mainly what library to use to obtain the informations i need) Thanx for your help Fabien Chaillou