tree 17ec0cca0bec472f5836039481545f35ad5ccbda
parent dc279ac29fcab1e0c1aa27bb56f7e2b514a04db9
author Glauber Costa <glommer@openvz.org> 1356360635 +0400
committer Glauber Costa <glommer@openvz.org> 1368624297 +0400

sched: introduce cgroup file stat_percpu

The file cpu.stat_percpu will show various scheduler related
information, that are usually available to the top level through other
files.

For instance, most of the meaningful data in /proc/stat is presented
here. Given this file, a container can easily construct a local copy of
/proc/stat for internal consumption.

The data we export is comprised of:
* all the tick information, previously available only through cpuacct,
  like user time, system time, etc.

* wait time, which can be used to construct analogous information to
  steal time in hypervisors,

* nr_switches and nr_running, which are cgroup-local versions of
  their global counterparts.

The file format consists of a one-line header that describes the fields
being listed.  No guarantee is given that the fields will be kept the
same between kernel releases, and readers should always check the header
in order to introspect it.

Each of the following lines will show the respective field value for
each of the possible cpus in the system. All values are show in
nanoseconds.

One example output for this file is:

cpu user nice system irq softirq guest guest_nice wait nr_switches nr_running
cpu0 471000000 0 15000000 0 0 0 0 1996534 7205 1
cpu1 588000000 0 17000000 0 0 0 0 2848680 6510 1
cpu2 505000000 0 14000000 0 0 0 0 2350771 6183 1
cpu3 472000000 0 16000000 0 0 0 0 19766345 6277 2

Signed-off-by: Glauber Costa <glommer@openvz.org>
CC: Peter Zijlstra <a.p.zijlstra@chello.nl>
CC: Paul Turner <pjt@google.com>