cpufreq: interactive: use deferrable timer by default
Avoid wakeups only to handle the governor timer when the system is otherwise
idle.
For platforms where the power cost of remaining in idle at higher CPU
speed may outweigh the cost of a governor wakeup from idle to lower the speed,
set parameter cpufreq_interactive.governidle=1.
Change-Id: Id6c43eb35caecf9b0574fcdd5b769711bc7e6de6
Signed-off-by: LianWei WANG <a22439@motorola.com>
Signed-off-by: Todd Poynor <toddpoynor@google.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
diff --git a/drivers/cpufreq/cpufreq_interactive.c b/drivers/cpufreq/cpufreq_interactive.c
index e53eae2..71887ca 100644
--- a/drivers/cpufreq/cpufreq_interactive.c
+++ b/drivers/cpufreq/cpufreq_interactive.c
@@ -20,6 +20,7 @@
#include <linux/cpumask.h>
#include <linux/cpufreq.h>
#include <linux/module.h>
+#include <linux/moduleparam.h>
#include <linux/mutex.h>
#include <linux/sched.h>
#include <linux/sched/rt.h>
@@ -92,6 +93,11 @@
static int boost_val;
+static bool governidle;
+module_param(governidle, bool, S_IWUSR | S_IRUGO);
+MODULE_PARM_DESC(governidle,
+ "Set to 1 to wake up CPUs from idle to reduce speed (default 0)");
+
static int cpufreq_governor_interactive(struct cpufreq_policy *policy,
unsigned int event);
@@ -240,10 +246,11 @@
rearm:
if (!timer_pending(&pcpu->cpu_timer)) {
/*
- * If already at min, cancel the timer if that CPU goes idle.
- * We don't need to re-evaluate speed until the next idle exit.
+ * If governing speed in idle and already at min, cancel the
+ * timer if that CPU goes idle. We don't need to re-evaluate
+ * speed until the next idle exit.
*/
- if (pcpu->target_freq == pcpu->policy->min)
+ if (governidle && pcpu->target_freq == pcpu->policy->min)
pcpu->timer_idlecancel = 1;
pcpu->time_in_idle = get_cpu_idle_time_us(
@@ -268,7 +275,6 @@
pending = timer_pending(&pcpu->cpu_timer);
if (pcpu->target_freq != pcpu->policy->min) {
-#ifdef CONFIG_SMP
/*
* Entering idle while not at lowest speed. On some
* platforms this can hold the other CPU(s) at that speed
@@ -285,8 +291,7 @@
&pcpu->cpu_timer,
jiffies + usecs_to_jiffies(timer_rate));
}
-#endif
- } else {
+ } else if (governidle) {
/*
* If at min speed and entering idle after load has
* already been evaluated, and a timer has been set just in
@@ -708,7 +713,10 @@
/* Initalize per-cpu timers */
for_each_possible_cpu(i) {
pcpu = &per_cpu(cpuinfo, i);
- init_timer(&pcpu->cpu_timer);
+ if (governidle)
+ init_timer(&pcpu->cpu_timer);
+ else
+ init_timer_deferrable(&pcpu->cpu_timer);
pcpu->cpu_timer.function = cpufreq_interactive_timer;
pcpu->cpu_timer.data = i;
}