Revert "cpuquiet: Update averaging of nr_runnables"

This reverts commit 8bd999a85354485af3cbee872816a9921d8bfffc.

bug 1050721

Change-Id: I29fcff431e5427dfaa2524a12c5702154037018a
Signed-off-by: Puneet Saxena <puneets@nvidia.com>
Reviewed-on: http://git-master/r/134307
Reviewed-by: Bharat Nihalani <bnihalani@nvidia.com>

3 files changed, 46 insertions, 26 deletions

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 974c9b2c0754..b8f4618407b2 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -2161,10 +2161,35 @@ unsigned long this_cpu_load(void)
 	return this->cpu_load[0];
 }
 
-u64 nr_running_integral(unsigned int cpu)
+unsigned long avg_nr_running(void)
+{
+	unsigned long i, sum = 0;
+	unsigned int seqcnt, ave_nr_running;
+
+	for_each_online_cpu(i) {
+		struct rq *q = cpu_rq(i);
+
+		/*
+		 * Update average to avoid reading stalled value if there were
+		 * no run-queue changes for a long time. On the other hand if
+		 * the changes are happening right now, just read current value
+		 * directly.
+		 */
+		seqcnt = read_seqcount_begin(&q->ave_seqcnt);
+		ave_nr_running = do_avg_nr_running(q);
+		if (read_seqcount_retry(&q->ave_seqcnt, seqcnt)) {
+			read_seqcount_begin(&q->ave_seqcnt);
+			ave_nr_running = q->ave_nr_running;
+		}
+
+		sum += ave_nr_running;
+	}
+
+	return sum;
+}
+
+unsigned long get_avg_nr_running(unsigned int cpu)
 {
-	unsigned int seqcnt;
-	u64 integral;
 	struct rq *q;
 
 	if (cpu >= nr_cpu_ids)
@@ -2172,21 +2197,7 @@ u64 nr_running_integral(unsigned int cpu)
 
 	q = cpu_rq(cpu);
 
-	/*
-	 * Update average to avoid reading stalled value if there were
-	 * no run-queue changes for a long time. On the other hand if
-	 * the changes are happening right now, just read current value
-	 * directly.
-	 */
-
-	seqcnt = read_seqcount_begin(&q->ave_seqcnt);
-	integral = do_nr_running_integral(q);
-	if (read_seqcount_retry(&q->ave_seqcnt, seqcnt)) {
-		read_seqcount_begin(&q->ave_seqcnt);
-		integral = q->nr_running_integral;
-	}
-
-	return integral;
+	return q->ave_nr_running;
 }
 
 /*
diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
index 09acaa15161d..06d172eb5cea 100644
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -266,6 +266,9 @@ static void print_cpu(struct seq_file *m, int cpu)
 	SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", #x, SPLIT_NS(rq->x))
 
 	P(nr_running);
+	SEQ_printf(m, "  .%-30s: %d.%03d   \n", "ave_nr_running",
+		   rq->ave_nr_running / FIXED_1,
+		   ((rq->ave_nr_running % FIXED_1) * 1000) / FIXED_1);
 	SEQ_printf(m, "  .%-30s: %lu\n", "load",
 		   rq->load.weight);
 	P(nr_switches);
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 99589411f980..ef5a1ff65196 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -365,7 +365,7 @@ struct rq {
 
 	/* time-based average load */
 	u64 nr_last_stamp;
-	u64 nr_running_integral;
+	unsigned int ave_nr_running;
 	seqcount_t ave_seqcnt;
 
 	/* capture load from *all* tasks on this cpu: */
@@ -924,26 +924,32 @@ static inline void cpuacct_charge(struct task_struct *tsk, u64 cputime) {}
  * 25 ~=  33554432ns =  33.5ms
  * 24 ~=  16777216ns =  16.8ms
  */
+#define NR_AVE_PERIOD_EXP	27
 #define NR_AVE_SCALE(x)		((x) << FSHIFT)
+#define NR_AVE_PERIOD		(1 << NR_AVE_PERIOD_EXP)
+#define NR_AVE_DIV_PERIOD(x)	((x) >> NR_AVE_PERIOD_EXP)
 
-
-static inline u64 do_nr_running_integral(struct rq *rq)
+static inline unsigned int do_avg_nr_running(struct rq *rq)
 {
 	s64 nr, deltax;
-	u64 nr_running_integral = rq->nr_running_integral;
+	unsigned int ave_nr_running = rq->ave_nr_running;
 
 	deltax = rq->clock_task - rq->nr_last_stamp;
 	nr = NR_AVE_SCALE(rq->nr_running);
 
-	nr_running_integral += nr * deltax;
+	if (deltax > NR_AVE_PERIOD)
+		ave_nr_running = nr;
+	else
+		ave_nr_running +=
+			NR_AVE_DIV_PERIOD(deltax * (nr - ave_nr_running));
 
-	return nr_running_integral;
+	return ave_nr_running;
 }
 
 static inline void inc_nr_running(struct rq *rq)
 {
 	write_seqcount_begin(&rq->ave_seqcnt);
-	rq->nr_running_integral = do_nr_running_integral(rq);
+	rq->ave_nr_running = do_avg_nr_running(rq);
 	rq->nr_last_stamp = rq->clock_task;
 	rq->nr_running++;
 	write_seqcount_end(&rq->ave_seqcnt);
@@ -952,7 +958,7 @@ static inline void inc_nr_running(struct rq *rq)
 static inline void dec_nr_running(struct rq *rq)
 {
 	write_seqcount_begin(&rq->ave_seqcnt);
-	rq->nr_running_integral = do_nr_running_integral(rq);
+	rq->ave_nr_running = do_avg_nr_running(rq);
 	rq->nr_last_stamp = rq->clock_task;
 	rq->nr_running--;
 	write_seqcount_end(&rq->ave_seqcnt);