From 5df7fa1c62146a0933767d040d400013310dbcc7 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Fri, 1 Feb 2008 17:45:14 +0100 Subject: [PATCH] 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 Signed-off-by: Ingo Molnar --- include/linux/tick.h | 4 ++++ kernel/time/tick-sched.c | 2 ++ kernel/time/timer_list.c | 2 ++ 3 files changed, 8 insertions(+) diff --git a/include/linux/tick.h b/include/linux/tick.h index 0fadf95debe1..a881c652f7e9 100644 --- a/include/linux/tick.h +++ b/include/linux/tick.h @@ -39,6 +39,8 @@ enum tick_nohz_mode { * @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 @@ struct tick_sched { 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 63f24b550695..88267f0a8471 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -137,6 +137,7 @@ void tick_nohz_update_jiffies(void) 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 @@ void tick_nohz_restart_sched_tick(void) * 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 12c5f4cb6b8c..d3d94c1a0fd2 100644 --- a/kernel/time/timer_list.c +++ b/kernel/time/timer_list.c @@ -166,6 +166,8 @@ static void print_cpu(struct seq_file *m, int cpu, u64 now) 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); -- 2.39.2