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authorBalbir Singh <balbir@linux.vnet.ibm.com>2007-10-19 02:39:44 -0400
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-10-19 14:53:36 -0400
commit846c7bb055747989891f5cd2bb6e8d56243ba1e7 (patch)
treee044041366efa8298157c4ae86615d68d30dd6d2 /Documentation
parentc2e2c7fa1cb2cf2b114a6c9bc132b6601db5a7c8 (diff)
Add cgroupstats
This patch 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. The patch is on top of 2.6.21-mm1 with Paul's cgroups v9 patches (forward ported) This patch implements per cgroup statistics infrastructure and re-uses code from the taskstats interface. A new set of cgroup operations are registered with commands and attributes. 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 file descriptor. Statistics about the state of all the tasks in the cgroup is returned to user space. TODO's/NOTE: This patch provides an infrastructure for implementing cgroup statistics. Based on the needs of each controller, we can incrementally add more statistics, event based support for notification of statistics, accumulation of taskstats into cgroup statistics in the future. Sample output # ./cgroupstats -C /cgroup/a sleeping 2, blocked 0, running 1, stopped 0, uninterruptible 0 # ./cgroupstats -C /cgroup/ sleeping 154, blocked 0, running 0, stopped 0, uninterruptible 0 If the approach looks good, I'll enhance and post the user space utility for the same Feedback, comments, test results are always welcome! [akpm@linux-foundation.org: build fix] Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Paul Menage <menage@google.com> Cc: Jay Lan <jlan@engr.sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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1Control Groupstats is inspired by the discussion at
2http://lkml.org/lkml/2007/4/11/187 and implements per cgroup statistics as
3suggested by Andrew Morton in http://lkml.org/lkml/2007/4/11/263.
4
5Per cgroup statistics infrastructure re-uses code from the taskstats
6interface. A new set of cgroup operations are registered with commands
7and attributes specific to cgroups. It should be very easy to
8extend per cgroup statistics, by adding members to the cgroupstats
9structure.
10
11The current model for cgroupstats is a pull, a push model (to post
12statistics on interesting events), should be very easy to add. Currently
13user space requests for statistics by passing the cgroup path.
14Statistics about the state of all the tasks in the cgroup is returned to
15user space.
16
17NOTE: We currently rely on delay accounting for extracting information
18about tasks blocked on I/O. If CONFIG_TASK_DELAY_ACCT is disabled, this
19information will not be available.
20
21To extract cgroup statistics a utility very similar to getdelays.c
22has been developed, the sample output of the utility is shown below
23
24~/balbir/cgroupstats # ./getdelays -C "/cgroup/a"
25sleeping 1, blocked 0, running 1, stopped 0, uninterruptible 0
26~/balbir/cgroupstats # ./getdelays -C "/cgroup"
27sleeping 155, blocked 0, running 1, stopped 0, uninterruptible 2