Re: [ckrm-tech] [PATCH 3/6] containers: Add generic multi-subsystem API to containers

[Balbir Singh <balbir@in.ibm.com>]

Paul Menage wrote:
> On 1/11/07, Balbir Singh <balbir@in.ibm.com> wrote:
> > to 0. To walk the hierarchy, I have no root now since I do not have
> > any task context. I was wondering if exporting the rootnode or providing
> > a function to export the rootnode of the mounter hierarchy will make
> > programming easier.
>
> Ah - I misunderstood what you were looking for before.

Here it is, a simple patch to keep track of percentage cpu load of a
container. This patch depends on the add mount callbacks patch and another
patch that fixes cpuacct for powerpc boxes (posted previously).

The patch attempts to add a percentage load calculation for each
container. It also maintains an accumulated time counter, which accounts
for the total cpu time taken by the container.

Compiled and tested on a 4 cpu powerpc box. Paul, please include this in
your next series of patches for containers.

Signed-off-by: <balbir@in.ibm.com>
---

 include/linux/cpu_acct.h |    4 ++
 kernel/cpu_acct.c        |   90 
+++++++++++++++++++++++++++++++++++++++++++----
 kernel/sched.c           |    7 ++-
 3 files changed, 93 insertions(+), 8 deletions(-)

diff -puN kernel/cpu_acct.c~cpu_acct_load_acct kernel/cpu_acct.c
--- linux-2.6.20-rc5/kernel/cpu_acct.c~cpu_acct_load_acct	2007-01-20 
18:28:26.000000000 +0530
+++ linux-2.6.20-rc5-balbir/kernel/cpu_acct.c	2007-01-20 22:32:49.000000000 
+0530
@@ -13,16 +13,22 @@
 #include <linux/module.h>
 #include <linux/container.h>
 #include <linux/fs.h>
+#include <linux/time.h>
 #include <asm/div64.h>

 struct cpuacct {
 	struct container_subsys_state css;
 	spinlock_t lock;
 	cputime64_t time; // total time used by this class
+	cputime64_t accum_time; // total time used by this class
 };

 static struct container_subsys cpuacct_subsys;
 static struct container *root;
+static spinlock_t interval_lock;
+static cputime64_t interval_time;
+static unsigned long long timestamp;
+static unsigned long long interval;

 static inline struct cpuacct *container_ca(struct container *cont)
 {
@@ -41,6 +47,8 @@ static int cpuacct_create(struct contain
 	if (!ca) return -ENOMEM;
 	spin_lock_init(&ca->lock);
 	cont->subsys[cpuacct_subsys.subsys_id] = &ca->css;
+	ca->time = cputime64_zero;
+	ca->accum_time = cputime64_zero;
 	return 0;
 }

@@ -67,17 +75,35 @@ static ssize_t cpuusage_read(struct cont
 			     size_t nbytes, loff_t *ppos)
 {
 	struct cpuacct *ca = container_ca(cont);
-	cputime64_t time;
-	unsigned long time_in_jiffies;
+	unsigned long long time;
+	unsigned long long accum_time;
+	unsigned long long interval_jiffies;
 	char usagebuf[64];
 	char *s = usagebuf;

 	spin_lock_irq(&ca->lock);
-	time = ca->time;
+	time = cputime64_to_jiffies64(ca->time);
+	accum_time = cputime64_to_jiffies64(ca->accum_time);
 	spin_unlock_irq(&ca->lock);

-	time_in_jiffies = cputime_to_jiffies(time);
-	s += sprintf(s, "%llu\n", (unsigned long long) time_in_jiffies);
+	spin_lock_irq(&interval_lock);
+	interval_jiffies = cputime64_to_jiffies64(interval_time);
+	spin_unlock_irq(&interval_lock);
+
+	s += sprintf(s, "time %llu\n", time);
+	s += sprintf(s, "accumulated time %llu\n", accum_time);
+	s += sprintf(s, "time since interval %llu\n", interval_jiffies);
+
+	/*
+	 * Calculate time in percentage
+	 */
+	time *= 100;
+	if (interval_jiffies)
+		do_div(time, interval_jiffies);
+	else
+		time = 0;
+
+	s += sprintf(s, "load %llu\n", time);

 	return simple_read_from_buffer(buf, nbytes, ppos, usagebuf, s - usagebuf);
 }
@@ -96,7 +122,6 @@ static int cpuacct_populate(struct conta

 void cpuacct_charge(struct task_struct *task, cputime_t cputime)
 {
-
 	struct cpuacct *ca;
 	unsigned long flags;

@@ -106,11 +131,60 @@ void cpuacct_charge(struct task_struct *
 	if (ca) {
 		spin_lock_irqsave(&ca->lock, flags);
 		ca->time = cputime64_add(ca->time, cputime);
+		ca->accum_time = cputime64_add(ca->accum_time, cputime);
 		spin_unlock_irqrestore(&ca->lock, flags);
 	}
 	rcu_read_unlock();
 }

+void cpuacct_uncharge(struct task_struct *task, cputime_t cputime)
+{
+	struct cpuacct *ca;
+	unsigned long flags;
+
+	if (cpuacct_subsys.subsys_id < 0 || !root) return;
+	rcu_read_lock();
+	ca = task_ca(task);
+	if (ca) {
+		spin_lock_irqsave(&ca->lock, flags);
+		ca->time = cputime64_sub(ca->time, cputime);
+		ca->accum_time = cputime64_sub(ca->accum_time, cputime);
+		spin_unlock_irqrestore(&ca->lock, flags);
+	}
+	rcu_read_unlock();
+}
+
+static void reset_ca_time(struct container *root)
+{
+	struct container *child;
+	struct cpuacct *ca;
+
+	if (root) {
+		ca = container_ca(root);
+		if (ca) {
+			spin_lock(&ca->lock);
+			ca->time = cputime64_zero;
+			spin_unlock(&ca->lock);
+		}
+		list_for_each_entry(child, &root->children, sibling)
+			reset_ca_time(child);
+	}
+}
+
+void cpuacct_update_time(cputime_t cputime)
+{
+	unsigned long flags;
+	unsigned long long timestamp_now = get_jiffies_64();
+	spin_lock_irqsave(&interval_lock, flags);
+	interval_time += cputime_to_cputime64(cputime);
+	if ((timestamp_now - timestamp) > interval) {
+		timestamp = timestamp_now;
+		reset_ca_time(root);
+		interval_time = cputime64_zero;
+	}
+	spin_unlock_irqrestore(&interval_lock, flags);
+}
+
 static struct container_subsys cpuacct_subsys = {
 	.name = "cpuacct",
 	.create = cpuacct_create,
@@ -127,6 +201,10 @@ int __init init_cpuacct(void)
 	int id;

 	root = NULL;
+	interval = 10 * HZ;
+	interval_time = cputime64_zero;
+	timestamp = get_jiffies_64();
+	spin_lock_init(&interval_lock);
 	id = container_register_subsys(&cpuacct_subsys);
 	return id < 0 ? id : 0;
 }
diff -puN kernel/sched.c~cpu_acct_load_acct kernel/sched.c
--- linux-2.6.20-rc5/kernel/sched.c~cpu_acct_load_acct	2007-01-20 
18:28:26.000000000 +0530
+++ linux-2.6.20-rc5-balbir/kernel/sched.c	2007-01-20 21:51:27.000000000 +0530
@@ -3078,7 +3078,7 @@ void account_user_time(struct task_struc
 	 */
 	if (p != rq->idle)
 		cpuacct_charge(p, cputime);
-
+	cpuacct_update_time(cputime);
 	/* Add user time to cpustat. */
 	tmp = cputime_to_cputime64(cputime);
 	if (TASK_NICE(p) > 0)
@@ -3100,6 +3100,7 @@ void account_system_time(struct task_str
 	struct rq *rq = this_rq();
 	cputime64_t tmp;

+	cpuacct_update_time(cputime);
 	p->stime = cputime_add(p->stime, cputime);

 	/* Add system time to cpustat. */
@@ -3136,8 +3137,10 @@ void account_steal_time(struct task_stru
 			cpustat->iowait = cputime64_add(cpustat->iowait, tmp);
 		else
 			cpustat->idle = cputime64_add(cpustat->idle, tmp);
-	} else
+	} else {
 		cpustat->steal = cputime64_add(cpustat->steal, tmp);
+		cpuacct_uncharge(p, tmp);
+	}
 }

 static void task_running_tick(struct rq *rq, struct task_struct *p)
diff -puN include/linux/cpu_acct.h~cpu_acct_load_acct include/linux/cpu_acct.h
--- linux-2.6.20-rc5/include/linux/cpu_acct.h~cpu_acct_load_acct	2007-01-20 
18:28:33.000000000 +0530
+++ linux-2.6.20-rc5-balbir/include/linux/cpu_acct.h	2007-01-20 
21:51:43.000000000 +0530
@@ -7,8 +7,12 @@

 #ifdef CONFIG_CONTAINER_CPUACCT
 extern void cpuacct_charge(struct task_struct *, cputime_t cputime);
+extern void cpuacct_uncharge(struct task_struct *, cputime_t cputime);
+extern void cpuacct_update_time(cputime_t cputime);
 #else
 static void inline cpuacct_charge(struct task_struct *p, cputime_t cputime) {}
+static void inline cpuacct_uncharge(struct task_struct *p, cputime_t 
cputime) {}
+static void inline cpuacct_update_time(cputime_t cputime) {}
 #endif

 #endif
_


--
	Balbir Singh
	Linux Technology Center
	IBM, ISTL
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