From 934352f214b3251eb0793c1209d346595a661d80 Mon Sep 17 00:00:00 2001 From: Bharata B Rao Date: Mon, 10 Nov 2008 20:41:13 +0530 Subject: sched: add hierarchical accounting to cpu accounting controller Impact: improve CPU time accounting of tasks under the cpu accounting controller Add hierarchical accounting to cpu accounting controller and include cpuacct documentation. Currently, while charging the task's cputime to its accounting group, the accounting group hierarchy isn't updated. This patch charges the cputime of a task to its accounting group and all its parent accounting groups. Reported-by: Srivatsa Vaddagiri Signed-off-by: Bharata B Rao Reviewed-by: Paul Menage Acked-by: Balbir Singh Acked-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- Documentation/controllers/cpuacct.txt | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) create mode 100644 Documentation/controllers/cpuacct.txt (limited to 'Documentation/controllers') diff --git a/Documentation/controllers/cpuacct.txt b/Documentation/controllers/cpuacct.txt new file mode 100644 index 000000000000..bb775fbe43d7 --- /dev/null +++ b/Documentation/controllers/cpuacct.txt @@ -0,0 +1,32 @@ +CPU Accounting Controller +------------------------- + +The CPU accounting controller is used to group tasks using cgroups and +account the CPU usage of these groups of tasks. + +The CPU accounting controller supports multi-hierarchy groups. An accounting +group accumulates the CPU usage of all of its child groups and the tasks +directly present in its group. + +Accounting groups can be created by first mounting the cgroup filesystem. + +# mkdir /cgroups +# mount -t cgroup -ocpuacct none /cgroups + +With the above step, the initial or the parent accounting group +becomes visible at /cgroups. At bootup, this group includes all the +tasks in the system. /cgroups/tasks lists the tasks in this cgroup. +/cgroups/cpuacct.usage gives the CPU time (in nanoseconds) obtained by +this group which is essentially the CPU time obtained by all the tasks +in the system. + +New accounting groups can be created under the parent group /cgroups. + +# cd /cgroups +# mkdir g1 +# echo $$ > g1 + +The above steps create a new group g1 and move the current shell +process (bash) into it. CPU time consumed by this bash and its children +can be obtained from g1/cpuacct.usage and the same is accumulated in +/cgroups/cpuacct.usage also. -- cgit v1.2.2