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authorIngo Molnar <mingo@elte.hu>2008-12-29 09:45:15 +0100
committerIngo Molnar <mingo@elte.hu>2008-12-29 09:45:15 +0100
commite1df957670aef74ffd9a4ad93e6d2c90bf6b4845 (patch)
treebca1fcfef55b3e3e82c9a822b4ac6428fce2b419 /Documentation/controllers/cpuacct.txt
parent2b583d8bc8d7105b58d7481a4a0ceb718dac49c6 (diff)
parent3c92ec8ae91ecf59d88c798301833d7cf83f2179 (diff)
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Merge branch 'linus' into perfcounters/core
Conflicts: fs/exec.c include/linux/init_task.h Simple context conflicts.
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+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.
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