Control Groupstats is inspired by the discussion at
  http://lkml.org/lkml/2007/4/11/187 and implements per cgroup statistics as
  suggested by Andrew Morton in http://lkml.org/lkml/2007/4/11/263.
  
  Per cgroup statistics infrastructure re-uses code from the taskstats
  interface. A new set of cgroup operations are registered with commands
  and attributes specific to cgroups. It should be very easy to
  extend per cgroup statistics, by adding members to the cgroupstats
  structure.
  
  The current model for cgroupstats is a pull, a push model (to post
  statistics on interesting events), should be very easy to add. Currently
  user space requests for statistics by passing the cgroup path.
  Statistics about the state of all the tasks in the cgroup is returned to
  user space.
  
  NOTE: We currently rely on delay accounting for extracting information
  about tasks blocked on I/O. If CONFIG_TASK_DELAY_ACCT is disabled, this
  information will not be available.
  
  To extract cgroup statistics a utility very similar to getdelays.c
  has been developed, the sample output of the utility is shown below

  ~/balbir/cgroupstats # ./getdelays  -C "/sys/fs/cgroup/a"

  sleeping 1, blocked 0, running 1, stopped 0, uninterruptible 0

  ~/balbir/cgroupstats # ./getdelays  -C "/sys/fs/cgroup"

  sleeping 155, blocked 0, running 1, stopped 0, uninterruptible 2