How to use cgroup in ubuntu 13.04

Question

I'm trying to learn how cgroup works on Ubuntu and seems that cgroup doesn't work in Ubuntu 13.04. I am using the answer to this question How to set cpu limit for given process permanently. Cpulimit and nice don't work

These are what I've done:

1. Installed cgroup:

   sudo apt-get install cgroup-bin
   

2. reboot

3. Make a cgroup for your user (the owner of the process):

   sudo cgcreate -a ipeacocks -g cpu:ipeacocks
   

4. Ran the command:

   echo 100 > /sys/fs/cgroup/cpu/ipeacocks/cpu.shares
   

5. And the command:

   cgexec -g cpu:ipeacocks stress --cpu 4
   

and output:

cgroup change of group failed

Why? What I am doing wrong?

Answer 1

You need to be the owner of the tasks file as well so you have permission to write a pid to it. To do that, Use -t, e.g.,

sudo cgcreate -a $USER:$USER -t $USER:$USER -g cpu:ipeacocks