* Baolin Wang <baolin.wang@xxxxxxxxxx> wrote:
> It will be more helpful to add some tracepoints to track RTC actions when
> debugging RTC driver. Below sample is that we set/read the RTC time, then
> set 2 alarms, so we can see the trace logs:
>
> set/read RTC time:
> kworker/1:1-586 [001] .... 21.826112: rtc_set_time: 2017-11-10 08:13:00 UTC (1510301580)
> kworker/1:1-586 [001] .... 21.826174: rtc_read_time: 2017-11-10 08:13:00 UTC (1510301580)
>
> set the first alarm timer:
> kworker/1:1-586 [001] .... 21.841098: rtc_timer_enqueue: RTC timer:(ffffffc15ad913c8) 2017-11-10 08:15:00 UTC (1510301700)
> kworker/1:1-586 [001] .... 22.009424: rtc_set_alarm: 2017-11-10 08:15:00 UTC (1510301700)
>
> set the second alarm timer:
> kworker/1:1-586 [001] .... 22.181304: rtc_timer_enqueue: RTC timer:(ffffff80088e6430) 2017-11-10 08:17:00 UTC (1510301820)
>
> the first alarm timer was expired:
> kworker/0:1-67 [000] .... 145.156226: rtc_timer_dequeue: RTC timer:(ffffffc15ad913c8) 2017-11-10 08:15:00 UTC (1510301700)
> kworker/0:1-67 [000] .... 145.156235: rtc_timer_fired: RTC timer:(ffffffc15ad913c8) 2017-11-10 08:15:00 UTC (1510301700)
> kworker/0:1-67 [000] .... 145.173137: rtc_set_alarm: 2017-11-10 08:17:00 UTC (1510301820)
>
> the second alarm timer was expired:
> kworker/0:1-67 [000] .... 269.102985: rtc_timer_dequeue: RTC timer:(ffffff80088e6430) 2017-11-10 08:17:00 UTC (1510301820)
> kworker/0:1-67 [000] .... 269.102992: rtc_timer_fired: RTC timer:(ffffff80088e6430) 2017-11-10 08:17:00 UTC (1510301820)
>
> disable alarm irq:
> kworker/0:1-67 [000] .... 269.103098: rtc_alarm_irq_enable: disable RTC alarm IRQ
>
> Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxx>
> ---
> drivers/rtc/interface.c | 46 ++++++++++
> include/trace/events/rtc.h | 215 ++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 261 insertions(+)
> create mode 100644 include/trace/events/rtc.h
>
> diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c
> index 8cec9a0..cdd3ac8 100644
> --- a/drivers/rtc/interface.c
> +++ b/drivers/rtc/interface.c
> @@ -17,6 +17,9 @@
> #include <linux/log2.h>
> #include <linux/workqueue.h>
>
> +#define CREATE_TRACE_POINTS
> +#include <trace/events/rtc.h>
> +
> static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer);
> static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer);
>
> @@ -53,6 +56,9 @@ int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm)
>
> err = __rtc_read_time(rtc, tm);
> mutex_unlock(&rtc->ops_lock);
> +
> + if (!err)
> + trace_rtc_read_time(tm);
It's better to just add unconditional tracepoints and trace the failures as well -
this makes things faster for the non-traced case, plus it's much easier to read as
well.
I.e. something like:
trace_rtc_read_time(tm, err);
etc.
> @@ -790,6 +818,8 @@ static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer)
> schedule_work(&rtc->irqwork);
> } else if (err) {
> timerqueue_del(&rtc->timerqueue, &timer->node);
> + trace_rtc_timer_dequeue(timer,
> + rtc_ktime_to_tm(timer->node.expires));
Please don't break the line in such an ugly fashion.
> @@ -803,6 +833,7 @@ static void rtc_alarm_disable(struct rtc_device *rtc)
> return;
>
> rtc->ops->alarm_irq_enable(rtc->dev.parent, false);
> + trace_rtc_alarm_irq_enable(0);
Since there's so many new events already, why not add an enable/disable variant
instead of parameterizing the 'enable' event?
> timerqueue_del(&rtc->timerqueue, &timer->node);
> + trace_rtc_timer_dequeue(timer, rtc_ktime_to_tm(timer->node.expires));
> + trace_rtc_timer_dequeue(timer,
> + rtc_ktime_to_tm(timer->node.expires));
> + trace_rtc_timer_fired(timer,
> + rtc_ktime_to_tm(timer->node.expires));
> + trace_rtc_timer_enqueue(timer,
> + rtc_ktime_to_tm(timer->node.expires));
All the decoding of expiry time should be done in the trace handler, don't bloat
the call site with it.
Thanks,
Ingo
