sched: cpufreq: Adds a field cpu_power in the task_struct

cpu_power has been added to keep track of amount of power each task is
consuming. cpu_power is updated whenever stime and utime are updated for
a task. power is computed by taking into account the frequency at which
the current core was running and the current for cpu actively
running at hat frequency.

Change-Id: Ic535941e7b339aab5cae9081a34049daeb44b248
Signed-off-by: Ruchi Kandoi <kandoiruchi@google.com>

5 files changed, 36 insertions, 0 deletions

diff --git a/drivers/cpufreq/cpufreq_stats.c b/drivers/cpufreq/cpufreq_stats.c
index 7f8e5a1b930c..3811168bf28d 100644
--- a/drivers/cpufreq/cpufreq_stats.c
+++ b/drivers/cpufreq/cpufreq_stats.c
@@ -15,6 +15,7 @@
 #include <linux/slab.h>
 #include <linux/sort.h>
 #include <linux/of.h>
+#include <linux/sched.h>
 #include <asm/cputime.h>
 
 static spinlock_t cpufreq_stats_lock;
@@ -125,6 +126,24 @@ static int get_index_all_cpufreq_stat(struct all_cpufreq_stats *all_stat,
 	return -1;
 }
 
+void acct_update_power(struct task_struct *task, cputime_t cputime) {
+	struct cpufreq_power_stats *powerstats;
+	struct cpufreq_stats *stats;
+	unsigned int cpu_num, curr;
+
+	if (!task)
+		return;
+	cpu_num = task_cpu(task);
+	powerstats = per_cpu(cpufreq_power_stats, cpu_num);
+	stats = per_cpu(cpufreq_stats_table, cpu_num);
+	if (!powerstats || !stats)
+		return;
+
+	curr = powerstats->curr[stats->last_index];
+	task->cpu_power += curr * cputime_to_usecs(cputime);
+}
+EXPORT_SYMBOL_GPL(acct_update_power);
+
 static ssize_t show_current_in_state(struct kobject *kobj,
 		struct kobj_attribute *attr, char *buf)
 {
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index b0d360c87602..a15944d5a06f 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -17,6 +17,8 @@
 #include <linux/kobject.h>
 #include <linux/notifier.h>
 #include <linux/sysfs.h>
+#include <asm/cputime.h>
+
 
 /*********************************************************************
  *                        CPUFREQ INTERFACE                          *
@@ -509,4 +511,10 @@ static inline int cpufreq_generic_exit(struct cpufreq_policy *policy)
 	return 0;
 }
 
+/*********************************************************************
+ *                         CPUFREQ STATS                             *
+ *********************************************************************/
+
+void acct_update_power(struct task_struct *p, cputime_t cputime);
+
 #endif /* _LINUX_CPUFREQ_H */
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 37658d063909..6aef9c64c73d 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1290,6 +1290,7 @@ struct task_struct {
 
 	cputime_t utime, stime, utimescaled, stimescaled;
 	cputime_t gtime;
+	unsigned long long cpu_power;
 #ifndef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
 	struct cputime prev_cputime;
 #endif
diff --git a/kernel/fork.c b/kernel/fork.c
index 02f89e3d75cd..42f05920e642 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1296,6 +1296,7 @@ static struct task_struct *copy_process(unsigned long clone_flags,
 
 	p->utime = p->stime = p->gtime = 0;
 	p->utimescaled = p->stimescaled = 0;
+	p->cpu_power = 0;
 #ifndef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
 	p->prev_cputime.utime = p->prev_cputime.stime = 0;
 #endif
diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
index 99947919e30b..582806c52752 100644
--- a/kernel/sched/cputime.c
+++ b/kernel/sched/cputime.c
@@ -1,3 +1,4 @@
+#include <linux/cpufreq.h>
 #include <linux/export.h>
 #include <linux/sched.h>
 #include <linux/tsacct_kern.h>
@@ -149,6 +150,9 @@ void account_user_time(struct task_struct *p, cputime_t cputime,
 
 	/* Account for user time used */
 	acct_account_cputime(p);
+
+	/* Account power usage for user time */
+	acct_update_power(p, cputime);
 }
 
 /*
@@ -199,6 +203,9 @@ void __account_system_time(struct task_struct *p, cputime_t cputime,
 
 	/* Account for system time used */
 	acct_account_cputime(p);
+
+	/* Account power usage for system time */
+	acct_update_power(p, cputime);
 }
 
 /*