cpufreq: interactive: specify duration of CPU speed boost pulse

Sysfs attribute boostpulse_duration specifies the duration of boosting CPU
speed in response to bootpulse events.  Duration is specified in usecs,
default 80ms.

Change-Id: Ifd41625574891a44f1787a4e85d1e7b4f2afb52b
Signed-off-by: Todd Poynor <toddpoynor@google.com>

1 files changed, 45 insertions, 7 deletions

diff --git a/drivers/cpufreq/cpufreq_interactive.c b/drivers/cpufreq/cpufreq_interactive.c
index e6c8e6fb45f..604f06af6dc 100644
--- a/drivers/cpufreq/cpufreq_interactive.c
+++ b/drivers/cpufreq/cpufreq_interactive.c
@@ -94,11 +94,12 @@ static unsigned long timer_rate;
 #define DEFAULT_ABOVE_HISPEED_DELAY DEFAULT_TIMER_RATE
 static unsigned long above_hispeed_delay_val;
 
-/*
- * Non-zero means longer-term speed boost active.
- */
-
+/* Non-zero means indefinite speed boost active */
 static int boost_val;
+/* Duration of a boot pulse in usecs */
+static int boostpulse_duration_val = DEFAULT_MIN_SAMPLE_TIME;
+/* End time of boost pulse in ktime converted to usecs */
+static u64 boostpulse_endtime;
 
 static bool governidle;
 module_param(governidle, bool, S_IWUSR | S_IRUGO);
@@ -267,6 +268,7 @@ static void cpufreq_interactive_timer(unsigned long data)
         unsigned int loadadjfreq;
         unsigned int index;
         unsigned long flags;
+        bool boosted;
 
         smp_rmb();
 
@@ -285,8 +287,9 @@ static void cpufreq_interactive_timer(unsigned long data)
         do_div(cputime_speedadj, delta_time);
         loadadjfreq = (unsigned int)cputime_speedadj * 100;
         cpu_load = loadadjfreq / pcpu->target_freq;
+        boosted = boost_val || now < boostpulse_endtime;
 
-        if ((cpu_load >= go_hispeed_load || boost_val) &&
+        if ((cpu_load >= go_hispeed_load || boosted) &&
             pcpu->target_freq < hispeed_freq)
                 new_freq = hispeed_freq;
         else
@@ -326,8 +329,18 @@ static void cpufreq_interactive_timer(unsigned long data)
                 }
         }
 
-        pcpu->floor_freq = new_freq;
-        pcpu->floor_validate_time = now;
+        /*
+         * Update the timestamp for checking whether speed has been held at
+         * or above the selected frequency for a minimum of min_sample_time,
+         * if not boosted to hispeed_freq.  If boosted to hispeed_freq then we
+         * allow the speed to drop as soon as the boostpulse duration expires
+         * (or the indefinite boost is turned off).
+         */
+
+        if (!boosted || new_freq > hispeed_freq) {
+                pcpu->floor_freq = new_freq;
+                pcpu->floor_validate_time = now;
+        }
 
         if (pcpu->target_freq == new_freq) {
                 trace_cpufreq_interactive_already(
@@ -773,6 +786,7 @@ static ssize_t store_boostpulse(struct kobject *kobj, struct attribute *attr,
         if (ret < 0)
                 return ret;
 
+        boostpulse_endtime = ktime_to_us(ktime_get()) + boostpulse_duration_val;
         trace_cpufreq_interactive_boost("pulse");
         cpufreq_interactive_boost();
         return count;
@@ -781,6 +795,29 @@ static ssize_t store_boostpulse(struct kobject *kobj, struct attribute *attr,
 static struct global_attr boostpulse =
         __ATTR(boostpulse, 0200, NULL, store_boostpulse);
 
+static ssize_t show_boostpulse_duration(
+        struct kobject *kobj, struct attribute *attr, char *buf)
+{
+        return sprintf(buf, "%d\n", boostpulse_duration_val);
+}
+
+static ssize_t store_boostpulse_duration(
+        struct kobject *kobj, struct attribute *attr, const char *buf,
+        size_t count)
+{
+        int ret;
+        unsigned long val;
+
+        ret = kstrtoul(buf, 0, &val);
+        if (ret < 0)
+                return ret;
+
+        boostpulse_duration_val = val;
+        return count;
+}
+
+define_one_global_rw(boostpulse_duration);
+
 static struct attribute *interactive_attributes[] = {
         &target_loads_attr.attr,
         &hispeed_freq_attr.attr,
@@ -790,6 +827,7 @@ static struct attribute *interactive_attributes[] = {
         &timer_rate_attr.attr,
         &boost.attr,
         &boostpulse.attr,
+        &boostpulse_duration.attr,
         NULL,
 };