using cpu.cfs_quota_us and cpu.cfs_period_us to limit CPU usage

There are 32 cores in a system (2 cpus each 16 cores) and I want to limit a user to use only 4 cores (100% usage for that 4 cores). There are two kernel parameter for that according to the manuals: cpu.cfs_quota_us and cpu.cfs_period_us An example on the kernel.org document says: With 500ms period and 1000ms quota, the group can get 2 CPUs worth of runtime every 500ms. # echo 1000000 > cpu.cfs_quota_us /* quota = 1000ms */ # echo 500000 > cpu.cfs_period_us /* period = 500ms */ I want to know how those ms are determined? In my case, I think the quota is 32000000 and the period is 4000000. Am I right? The content of etc/cgconfig.conf is: group ansys { cpu { cpu.cfs_quota_us = 32000000; cpu.cfs_period_us = 4000000; } memory { memory.limit_in_bytes = 8000m; } } But it doesn't work! and I get an error when I run /etc.init.d.cgconfig start, I get this error: Failed to parse /etc/cgconfig.conf or /etc/cgconfig.d [FAILED]Starting cgconfig service: /sbin/cgconfigparser; error loading /etc/cgconfig.conf: Failed to remove a non-empty group