tick-sched: add more debug information
To allow better diagnosis of tick-sched related, especially NOHZ
related problems, we need to know when the last wakeup via an irq
happened and when the CPU left the idle state.
Add two fields (idle_waketime, idle_exittime) to the tick_sched
structure and add them to the timer_list output.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/include/linux/tick.h b/include/linux/tick.h
index 0fadf95d..a881c65 100644
--- a/include/linux/tick.h
+++ b/include/linux/tick.h
@@ -39,6 +39,8 @@
* @idle_calls: Total number of idle calls
* @idle_sleeps: Number of idle calls, where the sched tick was stopped
* @idle_entrytime: Time when the idle call was entered
+ * @idle_waketime: Time when the idle was interrupted
+ * @idle_exittime: Time when the idle state was left
* @idle_sleeptime: Sum of the time slept in idle with sched tick stopped
* @sleep_length: Duration of the current idle sleep
*/
@@ -53,6 +55,8 @@
unsigned long idle_sleeps;
int idle_active;
ktime_t idle_entrytime;
+ ktime_t idle_waketime;
+ ktime_t idle_exittime;
ktime_t idle_sleeptime;
ktime_t idle_lastupdate;
ktime_t sleep_length;
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 63f24b5..88267f0 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -137,6 +137,7 @@
cpu_clear(cpu, nohz_cpu_mask);
now = ktime_get();
+ ts->idle_waketime = now;
local_irq_save(flags);
tick_do_update_jiffies64(now);
@@ -400,6 +401,7 @@
* Cancel the scheduled timer and restore the tick
*/
ts->tick_stopped = 0;
+ ts->idle_exittime = now;
hrtimer_cancel(&ts->sched_timer);
ts->sched_timer.expires = ts->idle_tick;
diff --git a/kernel/time/timer_list.c b/kernel/time/timer_list.c
index 12c5f4c..d3d94c1 100644
--- a/kernel/time/timer_list.c
+++ b/kernel/time/timer_list.c
@@ -166,6 +166,8 @@
P(idle_calls);
P(idle_sleeps);
P_ns(idle_entrytime);
+ P_ns(idle_waketime);
+ P_ns(idle_exittime);
P_ns(idle_sleeptime);
P(last_jiffies);
P(next_jiffies);