@NotMe that sounds like a bug, but I’m unable to reproduce it, at least on my macOS machine (I haven’t tried Linux yet).
If I run talker or listener I get a steady 4.7Mb of memory usage for both. If I modify it like this to create 40 of each publisher/subscriber (each on a different topic):
I still only about 8.4Mb of memory usage for each.
Maybe you could provide a similarly minimal example which has this problem? We haven’t gotten to the point where we are profiling to look for unintended memory usage, so there might be a bug in there.
Also, I’m using the master branch, which version of ROS2 are you using? That might affect your Fast-RTPS version and maybe the issue you’re seeing is already addressed on master.