cpuquiet: Updated balanced governor to use the runnable threads patch

The balanced governor now looks at the average number of runnable
threads when bringing cores online and offline. The balanced governor
parameters have also been updated to reflect a similar patch for
autohotplug.

Change-Id: I8dac26659ba43d95a68830c6cc268591a7f03f80
Signed-off-by: Sai Charan Gurrappadi <sgurrappadi@nvidia.com>
Reviewed-on: http://git-master/r/111282
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Peter De Schrijver <pdeschrijver@nvidia.com>
Reviewed-by: Peter Boonstoppel <pboonstoppel@nvidia.com>
GVS: Gerrit_Virtual_Submit
Reviewed-by: Aleksandr Frid <afrid@nvidia.com>
Reviewed-by: Yu-Huan Hsu <yhsu@nvidia.com>

1 files changed, 44 insertions, 9 deletions

diff --git a/drivers/cpuquiet/governors/balanced.c b/drivers/cpuquiet/governors/balanced.c
index 270bbf5d1f28..968344e220d9 100644
--- a/drivers/cpuquiet/governors/balanced.c
+++ b/drivers/cpuquiet/governors/balanced.c
@@ -72,12 +72,13 @@ struct balanced_attribute {
 }
 
 /* configurable parameters */
-static unsigned long balance_level = 75;
+static unsigned long balance_level = 60;
 static unsigned long idle_bottom_freq;
 static unsigned long idle_top_freq;
 static unsigned long up_delay;
 static unsigned long down_delay;
-
+static unsigned long last_change_time;
+static unsigned long load_sample_rate = 20; // msec
 static struct workqueue_struct *balanced_wq;
 static struct delayed_work balanced_work;
 static BALANCED_STATE balanced_state;
@@ -106,7 +107,7 @@ static void calculate_load_timer(unsigned long data)
 		do_div(idle_time, elapsed_time);
 		*load = 100 - idle_time;
 	}
-	mod_timer(&load_timer, jiffies + msecs_to_jiffies(100));
+	mod_timer(&load_timer, jiffies + msecs_to_jiffies(load_sample_rate));
 }
 
 static void start_load_timer(void)
@@ -183,6 +184,14 @@ static unsigned int count_slow_cpus(unsigned int limit)
 	return cnt;
 }
 
+#define NR_FSHIFT	2
+static unsigned int nr_run_thresholds[] = {
+/*      1,  2,  3,  4 - on-line cpus target */
+	5,  9, 10, UINT_MAX /* avg run threads * 4 (e.g., 9 = 2.25 threads) */
+};
+static unsigned int nr_run_hysteresis = 2;	/* 0.5 thread */
+static unsigned int nr_run_last;
+
 static CPU_SPEED_BALANCE balanced_speed_balance(void)
 {
 	unsigned long highest_speed = cpu_highest_speed();
@@ -190,14 +199,27 @@ static CPU_SPEED_BALANCE balanced_speed_balance(void)
 	unsigned long skewed_speed = balanced_speed / 2;
 	unsigned int nr_cpus = num_online_cpus();
 	unsigned int max_cpus = pm_qos_request(PM_QOS_MAX_ONLINE_CPUS) ? : 4;
+	unsigned int avg_nr_run = avg_nr_running();
+	unsigned int nr_run;
 
 	/* balanced: freq targets for all CPUs are above 50% of highest speed
 	   biased: freq target for at least one CPU is below 50% threshold
 	   skewed: freq targets for at least 2 CPUs are below 25% threshold */
-	if (count_slow_cpus(skewed_speed) >= 2 || nr_cpus > max_cpus)
+	for (nr_run = 1; nr_run < ARRAY_SIZE(nr_run_thresholds); nr_run++) {
+		unsigned int nr_threshold = nr_run_thresholds[nr_run - 1];
+		if (nr_run_last <= nr_run)
+			nr_threshold += nr_run_hysteresis;
+		if (avg_nr_run <= (nr_threshold << (FSHIFT - NR_FSHIFT)))
+			break;
+	}
+	nr_run_last = nr_run;
+
+	if (count_slow_cpus(skewed_speed) >= 2 || nr_cpus > max_cpus ||
+		nr_run < nr_cpus)
 		return CPU_SPEED_SKEWED;
 
-	if (count_slow_cpus(balanced_speed) >= 1 || nr_cpus == max_cpus)
+	if (count_slow_cpus(balanced_speed) >= 1 || nr_cpus == max_cpus ||
+		nr_run <= nr_cpus)
 		return CPU_SPEED_BIASED;
 
 	return CPU_SPEED_BALANCED;
@@ -207,6 +229,8 @@ static void balanced_work_func(struct work_struct *work)
 {
 	bool up = false;
 	unsigned int cpu = nr_cpu_ids;
+	unsigned long now = jiffies;
+
 	CPU_SPEED_BALANCE balance;
 
 	switch (balanced_state) {
@@ -217,7 +241,7 @@ static void balanced_work_func(struct work_struct *work)
 		if (cpu < nr_cpu_ids) {
 			up = false;
 			queue_delayed_work(balanced_wq,
-						 &balanced_work, down_delay);
+						 &balanced_work, up_delay);
 		} else
 			stop_load_timer();
 		break;
@@ -250,7 +274,11 @@ static void balanced_work_func(struct work_struct *work)
 		       __func__, balanced_state);
 	}
 
+	if (!up && ((now - last_change_time) < down_delay))
+		cpu = nr_cpu_ids;
+
 	if (cpu < nr_cpu_ids) {
+		last_change_time = now;
 		if (up)
 			cpuquiet_wake_cpu(cpu);
 		else
@@ -294,7 +322,7 @@ static int balanced_cpufreq_transition(struct notifier_block *nb,
 			if (cpu_freq <= idle_bottom_freq) {
 				balanced_state = DOWN;
 				queue_delayed_work(balanced_wq,
-					&balanced_work, down_delay);
+					&balanced_work, up_delay);
 				start_load_timer();
 			}
 			break;
@@ -357,6 +385,7 @@ BALANCED_ATTRIBUTE(idle_bottom_freq, 0644);
 BALANCED_ATTRIBUTE(idle_top_freq, 0644);
 BALANCED_ATTRIBUTE(up_delay, 0644);
 BALANCED_ATTRIBUTE(down_delay, 0644);
+BALANCED_ATTRIBUTE(load_sample_rate, 0644);
 
 static struct attribute *balanced_attributes[] = {
 	&balance_level_attr.attr,
@@ -419,6 +448,7 @@ static int balanced_start(void)
 {
 	int err, count;
 	struct cpufreq_frequency_table *table;
+	struct cpufreq_freqs initial_freq;
 
 	err = balanced_sysfs();
 	if (err)
@@ -431,8 +461,8 @@ static int balanced_start(void)
 
 	INIT_DELAYED_WORK(&balanced_work, balanced_work_func);
 
-	up_delay = msecs_to_jiffies(1000);
-	down_delay = msecs_to_jiffies(2000);
+	up_delay = msecs_to_jiffies(100);
+	down_delay = msecs_to_jiffies(500);
 
 	table = cpufreq_frequency_get_table(0);
 	for (count = 0; table[count].frequency != CPUFREQ_TABLE_END; count++)
@@ -447,6 +477,11 @@ static int balanced_start(void)
 	init_timer(&load_timer);
 	load_timer.function = calculate_load_timer;
 
+	/*FIXME: Kick start the state machine by faking a freq notification*/
+	initial_freq.new = cpufreq_get(0);
+	if (initial_freq.new != 0)
+		balanced_cpufreq_transition(NULL, CPUFREQ_RESUMECHANGE,
+						&initial_freq);
 	return 0;
 }