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Message-ID: <20161017150356.7dd37cae@gandalf.local.home>
Date: Mon, 17 Oct 2016 15:03:56 -0400
From: Steven Rostedt <rostedt@...dmis.org>
To: Baolin Wang <baolin.wang@...aro.org>
Cc: mingo@...hat.com, john.stultz@...aro.org, tglx@...utronix.de,
broonie@...nel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3] time: alarmtimer: Add the trcepoints for alarmtimer
On Tue, 11 Oct 2016 18:48:16 +0800
Baolin Wang <baolin.wang@...aro.org> wrote:
> For system debugging, we sometimes want to know who sets one
> alarm timer, the time of the timer, when the timer started and
> fired and so on. Thus adding tracepoints can help us trace the
> alarmtimer information.
>
> For example, when we debug the system supend/resume, if the
> system is always resumed by RTC alarm, we can find out which
> process set the alarm timer to resume system by below trace log:
>
> ......
>
> Binder:3292_2-3304 [000] d..2 149.981123: alarmtimer_cancel:
> alarmtimer:ffffffc1319a7800 type:ALARM_REALTIME
> expires:1325463120000000000 now:1325376810370370245
>
> Binder:3292_2-3304 [000] d..2 149.981136: alarmtimer_start:
> alarmtimer:ffffffc1319a7800 type:ALARM_REALTIME
> expires:1325376840000000000 now:1325376810370384591
>
> Binder:3292_9-3953 [000] d..2 150.212991: alarmtimer_cancel:
> alarmtimer:ffffffc1319a5a00 type:ALARM_BOOTTIME
> expires:179552000000 now:150154008122
>
> Binder:3292_9-3953 [000] d..2 150.213006: alarmtimer_start:
> alarmtimer:ffffffc1319a5a00 type:ALARM_BOOTTIME
> expires:179551000000 now:150154025622
>
> ......
>
> system_server-3000 [002] ...1 1087.737565: alarmtimer_suspend:
> alarmtimer type:ALARM_BOOTTIME expires: 1325376839802714584
>
> ......
>
> >From the trace log, we can find out the 'Binder:3292_2' process
> set one alarm timer which resumes the system.
>
> Signed-off-by: Baolin Wang <baolin.wang@...aro.org>
> ---
> Changes since v2:
> - Save time as s64 type.
> - Remove 'process_name' parameter and add 'now' parameter.
> - Rename the trace event name.
> - Remove restart trace event.
> - Other optimization.
> ---
> include/trace/events/alarmtimer.h | 92 +++++++++++++++++++++++++++++++++++++
> kernel/time/alarmtimer.c | 16 ++++++-
> 2 files changed, 106 insertions(+), 2 deletions(-)
> create mode 100644 include/trace/events/alarmtimer.h
>
> diff --git a/include/trace/events/alarmtimer.h b/include/trace/events/alarmtimer.h
> new file mode 100644
> index 0000000..4c92a3e
> --- /dev/null
> +++ b/include/trace/events/alarmtimer.h
> @@ -0,0 +1,92 @@
> +#undef TRACE_SYSTEM
> +#define TRACE_SYSTEM alarmtimer
> +
> +#if !defined(_TRACE_ALARMTIMER_H) || defined(TRACE_HEADER_MULTI_READ)
> +#define _TRACE_ALARMTIMER_H
> +
> +#include <linux/alarmtimer.h>
> +#include <linux/rtc.h>
> +#include <linux/tracepoint.h>
> +
> +TRACE_DEFINE_ENUM(ALARM_REALTIME);
> +TRACE_DEFINE_ENUM(ALARM_BOOTTIME);
> +
> +#define show_alarm_type(type) __print_flags(type, " | ", \
> + { 1 << ALARM_REALTIME, "ALARM_REALTIME" }, \
> + { 1 << ALARM_BOOTTIME, "ALARM_BOOTTIME" })
Why have the "ALARM_" prefix in the string? We already know that these
are "alarm" tracepoints. They just make the lines longer than they need
to be.
Other than that, from a tracing point of view, this looks fine to me.
Acked-by: Steven Rostedt <rostedt@...dmis.org>
-- Steve
> +
> +TRACE_EVENT(alarmtimer_suspend,
> +
> + TP_PROTO(ktime_t expires, int flag),
> +
> + TP_ARGS(expires, flag),
> +
> + TP_STRUCT__entry(
> + __field(s64, expires)
> + __field(unsigned char, alarm_type)
> + ),
> +
> + TP_fast_assign(
> + __entry->expires = expires.tv64;
> + __entry->alarm_type = flag;
> + ),
> +
> + TP_printk("alarmtimer type:%s expires:%llu",
> + show_alarm_type((1 << __entry->alarm_type)),
> + __entry->expires
> + )
> +);
> +
> +DECLARE_EVENT_CLASS(alarm_class,
> +
> + TP_PROTO(struct alarm *alarm, ktime_t now),
> +
> + TP_ARGS(alarm, now),
> +
> + TP_STRUCT__entry(
> + __field(void *, alarm)
> + __field(unsigned char, alarm_type)
> + __field(s64, expires)
> + __field(s64, now)
> + ),
> +
> + TP_fast_assign(
> + __entry->alarm = alarm;
> + __entry->alarm_type = alarm->type;
> + __entry->expires = alarm->node.expires.tv64;
> + __entry->now = now.tv64;
> + ),
> +
> + TP_printk("alarmtimer:%p type:%s expires:%llu now:%llu",
> + __entry->alarm,
> + show_alarm_type((1 << __entry->alarm_type)),
> + __entry->expires,
> + __entry->now
> + )
> +);
> +
> +DEFINE_EVENT(alarm_class, alarmtimer_fired,
> +
> + TP_PROTO(struct alarm *alarm, ktime_t now),
> +
> + TP_ARGS(alarm, now)
> +);
> +
> +DEFINE_EVENT(alarm_class, alarmtimer_start,
> +
> + TP_PROTO(struct alarm *alarm, ktime_t now),
> +
> + TP_ARGS(alarm, now)
> +);
> +
> +DEFINE_EVENT(alarm_class, alarmtimer_cancel,
> +
> + TP_PROTO(struct alarm *alarm, ktime_t now),
> +
> + TP_ARGS(alarm, now)
> +);
> +
> +#endif /* _TRACE_ALARMTIMER_H */
> +
> +/* This part must be outside protection */
> +#include <trace/define_trace.h>
> diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c
> index c3aad68..4e10dad 100644
> --- a/kernel/time/alarmtimer.c
> +++ b/kernel/time/alarmtimer.c
> @@ -26,6 +26,9 @@
> #include <linux/workqueue.h>
> #include <linux/freezer.h>
>
> +#define CREATE_TRACE_POINTS
> +#include <trace/events/alarmtimer.h>
> +
> /**
> * struct alarm_base - Alarm timer bases
> * @lock: Lock for syncrhonized access to the base
> @@ -194,6 +197,7 @@ static enum hrtimer_restart alarmtimer_fired(struct hrtimer *timer)
> }
> spin_unlock_irqrestore(&base->lock, flags);
>
> + trace_alarmtimer_fired(alarm, base->gettime());
> return ret;
>
> }
> @@ -222,7 +226,7 @@ static int alarmtimer_suspend(struct device *dev)
> ktime_t min, now;
> unsigned long flags;
> struct rtc_device *rtc;
> - int i;
> + int i, type = 0;
> int ret;
>
> spin_lock_irqsave(&freezer_delta_lock, flags);
> @@ -247,8 +251,10 @@ static int alarmtimer_suspend(struct device *dev)
> if (!next)
> continue;
> delta = ktime_sub(next->expires, base->gettime());
> - if (!min.tv64 || (delta.tv64 < min.tv64))
> + if (!min.tv64 || (delta.tv64 < min.tv64)) {
> min = delta;
> + type = i;
> + }
> }
> if (min.tv64 == 0)
> return 0;
> @@ -264,6 +270,8 @@ static int alarmtimer_suspend(struct device *dev)
> now = rtc_tm_to_ktime(tm);
> now = ktime_add(now, min);
>
> + trace_alarmtimer_suspend(now, type);
> +
> /* Set alarm, if in the past reject suspend briefly to handle */
> ret = rtc_timer_start(rtc, &rtctimer, now, ktime_set(0, 0));
> if (ret < 0)
> @@ -342,6 +350,8 @@ void alarm_start(struct alarm *alarm, ktime_t start)
> alarmtimer_enqueue(base, alarm);
> hrtimer_start(&alarm->timer, alarm->node.expires, HRTIMER_MODE_ABS);
> spin_unlock_irqrestore(&base->lock, flags);
> +
> + trace_alarmtimer_start(alarm, base->gettime());
> }
> EXPORT_SYMBOL_GPL(alarm_start);
>
> @@ -390,6 +400,8 @@ int alarm_try_to_cancel(struct alarm *alarm)
> if (ret >= 0)
> alarmtimer_dequeue(base, alarm);
> spin_unlock_irqrestore(&base->lock, flags);
> +
> + trace_alarmtimer_cancel(alarm, base->gettime());
> return ret;
> }
> EXPORT_SYMBOL_GPL(alarm_try_to_cancel);
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