“The Completely Fair Scheduler (CFS) was merged for the 2.6.23
kernel. One CFS feature which did not get in, though, was the group
scheduling facility. Group scheduling makes the CFS fairness
algorithm operate in a hierarchical fashion: processes are divided
into groups, and, within each group, processes are scheduled fairly
against one another. At the higher level, each group as a whole is
given a fair share of the processor. The grouping of processes is
done in user space in a highly flexible manner; the control groups
(formerly ‘process containers’) mechanism allows a management
daemon to classify processes according to almost any policy…”