Squashandroid-20111012

Change-Id: If0ae9fa8067740ab2ede33703c79ec134f204a5e

1 files changed, 50 insertions, 2 deletions

diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c
index e1314212d8d..a8d732c6fa6 100644
--- a/drivers/cpufreq/cpufreq_ondemand.c
+++ b/drivers/cpufreq/cpufreq_ondemand.c
@@ -30,6 +30,8 @@
 
 #define DEF_FREQUENCY_DOWN_DIFFERENTIAL		(10)
 #define DEF_FREQUENCY_UP_THRESHOLD		(80)
+#define DEF_SAMPLING_DOWN_FACTOR		(10)
+#define MAX_SAMPLING_DOWN_FACTOR		(100000)
 #define MICRO_FREQUENCY_DOWN_DIFFERENTIAL	(3)
 #define MICRO_FREQUENCY_UP_THRESHOLD		(95)
 #define MICRO_FREQUENCY_MIN_SAMPLE_RATE		(10000)
@@ -82,6 +84,7 @@ struct cpu_dbs_info_s {
 	unsigned int freq_lo;
 	unsigned int freq_lo_jiffies;
 	unsigned int freq_hi_jiffies;
+	unsigned int rate_mult;
 	int cpu;
 	unsigned int sample_type:1;
 	/*
@@ -108,10 +111,12 @@ static struct dbs_tuners {
 	unsigned int up_threshold;
 	unsigned int down_differential;
 	unsigned int ignore_nice;
+	unsigned int sampling_down_factor;
 	unsigned int powersave_bias;
 	unsigned int io_is_busy;
 } dbs_tuners_ins = {
 	.up_threshold = DEF_FREQUENCY_UP_THRESHOLD,
+	.sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR,
 	.down_differential = DEF_FREQUENCY_DOWN_DIFFERENTIAL,
 	.ignore_nice = 0,
 	.powersave_bias = 0,
@@ -259,6 +264,7 @@ static ssize_t show_##file_name						\
 show_one(sampling_rate, sampling_rate);
 show_one(io_is_busy, io_is_busy);
 show_one(up_threshold, up_threshold);
+show_one(sampling_down_factor, sampling_down_factor);
 show_one(ignore_nice_load, ignore_nice);
 show_one(powersave_bias, powersave_bias);
 
@@ -340,6 +346,29 @@ static ssize_t store_up_threshold(struct kobject *a, struct attribute *b,
 	return count;
 }
 
+static ssize_t store_sampling_down_factor(struct kobject *a,
+			struct attribute *b, const char *buf, size_t count)
+{
+	unsigned int input, j;
+	int ret;
+	ret = sscanf(buf, "%u", &input);
+
+	if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1)
+		return -EINVAL;
+	mutex_lock(&dbs_mutex);
+	dbs_tuners_ins.sampling_down_factor = input;
+
+	/* Reset down sampling multiplier in case it was active */
+	for_each_online_cpu(j) {
+		struct cpu_dbs_info_s *dbs_info;
+		dbs_info = &per_cpu(od_cpu_dbs_info, j);
+		dbs_info->rate_mult = 1;
+	}
+	mutex_unlock(&dbs_mutex);
+
+	return count;
+}
+
 static ssize_t store_ignore_nice_load(struct kobject *a, struct attribute *b,
 				      const char *buf, size_t count)
 {
@@ -401,6 +430,7 @@ static ssize_t store_powersave_bias(struct kobject *a, struct attribute *b,
 define_one_global_rw(sampling_rate);
 define_one_global_rw(io_is_busy);
 define_one_global_rw(up_threshold);
+define_one_global_rw(sampling_down_factor);
 define_one_global_rw(ignore_nice_load);
 define_one_global_rw(powersave_bias);
 
@@ -409,6 +439,7 @@ static struct attribute *dbs_attributes[] = {
 	&sampling_rate_min.attr,
 	&sampling_rate.attr,
 	&up_threshold.attr,
+	&sampling_down_factor.attr,
 	&ignore_nice_load.attr,
 	&powersave_bias.attr,
 	&io_is_busy.attr,
@@ -551,6 +582,10 @@ static void dbs_check_cpu(struct cpu_dbs_info_s *this_dbs_info)
 
 	/* Check for frequency increase */
 	if (max_load_freq > dbs_tuners_ins.up_threshold * policy->cur) {
+		/* If switching to max speed, apply sampling_down_factor */
+		if (policy->cur < policy->max)
+			this_dbs_info->rate_mult =
+				dbs_tuners_ins.sampling_down_factor;
 		/* if we are already at full speed then break out early */
 		if (!dbs_tuners_ins.powersave_bias) {
 			if (policy->cur == policy->max)
@@ -585,6 +620,9 @@ static void dbs_check_cpu(struct cpu_dbs_info_s *this_dbs_info)
 				(dbs_tuners_ins.up_threshold -
 				 dbs_tuners_ins.down_differential);
 
+		/* No longer fully busy, reset rate_mult */
+		this_dbs_info->rate_mult = 1;
+
 		if (freq_next < policy->min)
 			freq_next = policy->min;
 
@@ -608,9 +646,12 @@ static void do_dbs_timer(struct work_struct *work)
 	int sample_type = dbs_info->sample_type;
 
 	/* We want all CPUs to do sampling nearly on same jiffy */
-	int delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate);
+	int delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate
+				     * dbs_info->rate_mult);
+
+	if (num_online_cpus() > 1)
+		delay -= jiffies % delay;
 
-	delay -= jiffies % delay;
 	mutex_lock(&dbs_info->timer_mutex);
 
 	/* Common NORMAL_SAMPLE setup */
@@ -622,10 +663,16 @@ static void do_dbs_timer(struct work_struct *work)
 			/* Setup timer for SUB_SAMPLE */
 			dbs_info->sample_type = DBS_SUB_SAMPLE;
 			delay = dbs_info->freq_hi_jiffies;
+		} else {
+			/* We want all CPUs to do sampling nearly on same jiffy */
+			delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate
+				* dbs_info->rate_mult);
+			delay -= jiffies % delay;
 		}
 	} else {
 		__cpufreq_driver_target(dbs_info->cur_policy,
 			dbs_info->freq_lo, CPUFREQ_RELATION_H);
+		delay = dbs_info->freq_lo_jiffies;
 	}
 	queue_delayed_work_on(cpu, kondemand_wq, &dbs_info->work, delay);
 	mutex_unlock(&dbs_info->timer_mutex);
@@ -708,6 +755,7 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
 			}
 		}
 		this_dbs_info->cpu = cpu;
+		this_dbs_info->rate_mult = 1;
 		ondemand_powersave_bias_init_cpu(cpu);
 		/*
 		 * Start the timerschedule work, when this governor