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>

diff --git a/drivers/cpufreq/cpufreq_interactive.c b/drivers/cpufreq/cpufreq_interactive.c
index d0d51ee30727dda728a9a9902a04b45d3f6b2460..8b44a82aa14630587bbb3e9a6c891827ebcf2a5c 100644 (file)
--- a/drivers/cpufreq/cpufreq_interactive.c
+++ b/drivers/cpufreq/cpufreq_interactive.c
@@ -95,11 +95,12 @@ 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);
@@ -268,6 +269,7 @@ static void cpufreq_interactive_timer(unsigned long data)
        unsigned int loadadjfreq;
        unsigned int index;
        unsigned long flags;
+       bool boosted;
 
        smp_rmb();
 
@@ -286,8 +288,9 @@ 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
@@ -327,8 +330,18 @@ 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(
@@ -774,6 +787,7 @@ 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;
@@ -782,6 +796,29 @@ 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,
@@ -791,6 +828,7 @@ static struct attribute *interactive_attributes[] = {
        &timer_rate_attr.attr,
        &boost.attr,
        &boostpulse.attr,
+       &boostpulse_duration.attr,
        NULL,
 };