| 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 "/cgroup/a" |
| sleeping 1, blocked 0, running 1, stopped 0, uninterruptible 0 |
| ~/balbir/cgroupstats # ./getdelays -C "/cgroup" |
| sleeping 155, blocked 0, running 1, stopped 0, uninterruptible 2 |
