I am trying to use cgroups to isolate a cpu core for a program that is performance sensitive. I was able to create a cgroup using the following cmds and I see my cgroup is created and the cpuset.cpus has #2 in it.

mkdir /sys/fs/cgroup/cpu/cg1
echo 2 > /sys/fs/cgroup/cpuset/cg1/cpuset.cpus

However, I ran the stress to load all of my cpus (total of 12) and I see cpu 2 is loaded.
Can you please let me know what I am missing here?
Please note that I am new to this concept!.