From: Quan Xu <quan.xu0 at gmail.com>
the last idle loop is from tick_nohz_idle_enter to tick_nohz_idle_exit.
Signed-off-by: Yang Zhang <yang.zhang.wz at gmail.com>
Signed-off-by: Quan Xu <quan.xu0 at gmail.com>
Cc: Frederic Weisbecker <fweisbec at gmail.com>
Cc: Thomas Gleixner <tglx at linutronix.de>
Cc: Ingo Molnar <mingo at kernel.org>
Cc: linux-kernel at vger.kernel.org
---
include/linux/tick.h | 2 ++
kernel/time/tick-sched.c | 11 +++++++++++
kernel/time/tick-sched.h | 3 +++
3 files changed, 16 insertions(+), 0 deletions(-)
diff --git a/include/linux/tick.h b/include/linux/tick.h
index cf413b3..77ae46d 100644
--- a/include/linux/tick.h
+++ b/include/linux/tick.h
@@ -118,6 +118,7 @@ enum tick_dep_bits {
extern void tick_nohz_idle_exit(void);
extern void tick_nohz_irq_exit(void);
extern ktime_t tick_nohz_get_sleep_length(void);
+extern ktime_t tick_nohz_get_last_idle_length(void);
extern unsigned long tick_nohz_get_idle_calls(void);
extern u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time);
extern u64 get_cpu_iowait_time_us(int cpu, u64 *last_update_time);
@@ -127,6 +128,7 @@ enum tick_dep_bits {
static inline void tick_nohz_idle_enter(void) { }
static inline void tick_nohz_idle_exit(void) { }
+static ktime_t tick_nohz_get_last_idle_length(void) { return -1; }
static inline ktime_t tick_nohz_get_sleep_length(void)
{
return NSEC_PER_SEC / HZ;
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index c7a899c..65c9cc0 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -548,6 +548,7 @@ static void tick_nohz_update_jiffies(ktime_t now)
else
ts->idle_sleeptime = ktime_add(ts->idle_sleeptime, delta);
ts->idle_entrytime = now;
+ ts->idle_length = delta;
}
if (last_update_time)
@@ -998,6 +999,16 @@ void tick_nohz_irq_exit(void)
}
/**
+ * tick_nohz_get_last_idle_length - return the length of the last idle loop
+ */
+ktime_t tick_nohz_get_last_idle_length(void)
+{
+ struct tick_sched *ts = this_cpu_ptr(&tick_cpu_sched);
+
+ return ts->idle_length;
+}
+
+/**
* tick_nohz_get_sleep_length - return the length of the current sleep
*
* Called from power state control code with interrupts disabled
diff --git a/kernel/time/tick-sched.h b/kernel/time/tick-sched.h
index 954b43d..2630cf9 100644
--- a/kernel/time/tick-sched.h
+++ b/kernel/time/tick-sched.h
@@ -39,6 +39,8 @@ enum tick_nohz_mode {
* @idle_sleeptime: Sum of the time slept in idle with sched tick stopped
* @iowait_sleeptime: Sum of the time slept in idle with sched tick stopped,
with IO outstanding
* @sleep_length: Duration of the current idle sleep
+ * @idle_length: Duration of the last idle loop is from
+ * tick_nohz_idle_enter to tick_nohz_idle_exit.
* @do_timer_lst: CPU was the last one doing do_timer before going idle
*/
struct tick_sched {
@@ -59,6 +61,7 @@ struct tick_sched {
ktime_t idle_sleeptime;
ktime_t iowait_sleeptime;
ktime_t sleep_length;
+ ktime_t idle_length;
unsigned long last_jiffies;
u64 next_timer;
ktime_t idle_expires;
--
1.7.1
