sched: add hierarchical accounting to cpu accounting controller (934352f2) · Commits · 戴 / test

Documentation/controllers/cpuacct.txt

0 → 100644

+32 −0

Original line number	Diff line number	Diff line
		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.

+9 −3

Original line number	Diff line number	Diff line
		@@ -9196,11 +9196,12 @@ struct cgroup_subsys cpu_cgroup_subsys = {
		* (balbir@in.ibm.com).
		*/

		/* track cpu usage of a group of tasks */
		/* track cpu usage of a group of tasks and its child groups */
		struct cpuacct {
		struct cgroup_subsys_state css;
		/* cpuusage holds pointer to a u64-type object on every cpu */
		u64 *cpuusage;
		struct cpuacct *parent;
		};

		struct cgroup_subsys cpuacct_subsys;
		@@ -9234,6 +9235,9 @@ static struct cgroup_subsys_state *cpuacct_create(
		return ERR_PTR(-ENOMEM);
		}

		if (cgrp->parent)
		ca->parent = cgroup_ca(cgrp->parent);

		return &ca->css;
		}

		@@ -9313,14 +9317,16 @@ static int cpuacct_populate(struct cgroup_subsys ss, struct cgroup cgrp)
		static void cpuacct_charge(struct task_struct *tsk, u64 cputime)
		{
		struct cpuacct *ca;
		int cpu;

		if (!cpuacct_subsys.active)
		return;

		cpu = task_cpu(tsk);
		ca = task_ca(tsk);
		if (ca) {
		u64 *cpuusage = percpu_ptr(ca->cpuusage, task_cpu(tsk));

		for (; ca; ca = ca->parent) {
		u64 *cpuusage = percpu_ptr(ca->cpuusage, cpu);
		*cpuusage += cputime;
		}
		}