linux-kernel - Re: [PATCH v4] time: alarmtimer: Add the trcepoints for alarmtimer

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Date:   Wed, 7 Sep 2016 14:22:32 +0800
From:   Baolin Wang <baolin.wang@...aro.org>
To:     John Stultz <john.stultz@...aro.org>
Cc:     Steven Rostedt <rostedt@...dmis.org>,
        Ingo Molnar <mingo@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Mark Brown <broonie@...nel.org>,
        lkml <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v4] time: alarmtimer: Add the trcepoints for alarmtimer

Hi John,

On 7 September 2016 at 14:17, John Stultz <john.stultz@...aro.org> wrote:
> On Tue, Sep 6, 2016 at 11:06 PM, 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:2976_6-3473  [005] d..2  1076.587732: alarmtimer_start:
>> process:Binder:2976_6
>> alarmtimer type:ALARM_BOOTTIME expires:1234154000000 time: 1970-1-1
>> 0:20:35
>>
>> Binder:2976_7-3480  [002] d..2  1076.592707: alarmtimer_cancel:
>> process:Binder:2976_7
>> alarmtimer type:ALARM_BOOTTIME expires:1325463060000000000 time:
>> 2012-1-2 0:11:0
>>
>> Binder:2976_7-3480  [002] d..2  1076.592731: alarmtimer_start:
>> process:Binder:2976_7
>> alarmtimer type:ALARM_BOOTTIME expires:1325378040000000000 time:
>> 2012-1-1 0:34:0
>>
>> system_server-2976  [003] d..2  1076.605587: alarmtimer_cancel:
>> process:system_server
>> alarmtimer type:ALARM_BOOTTIME expires:1234154000000 time: 1970-1-1
>> 0:20:35
>>
>> system_server-2976  [003] d..2  1076.605608: alarmtimer_start:
>> process:system_server
>> alarmtimer type:ALARM_BOOTTIME expires:1234155000000 time: 1970-1-1
>> 0:20:35
>>
>> system_server-3000  [002] ...1  1087.737565: alarmtimer_suspend:
>> alarmtimer type:ALARM_BOOTTIME
>> expires time: 2012-1-1 0:34:0
>> ......
>>
>> From the trace log, we can find out the 'Binder:2976_7' process
>> set one alarm timer which resumes the system.
>>
>> Signed-off-by: Baolin Wang <baolin.wang@...aro.org>
>> Acked-by: Steven Rostedt <rostedt@...dmis.org>
>> ---
>> Changes since v3:
>>  - Fix the build error on S390.
>
> Since the original change is already applied to tip/timers/core, can
> you provide an incremental patch (a patch against tip/timers/core)
> that fixes the issue, rather then resending the entire patch?

OK.

>
> Also, the "#ifdef CONFIG_RTC_LIB" solution I proposed was sort of a
> hack, so I'd hope to see something better.
>
> One better solution would be to add a dummy static inline
> implementation of rtc_ktime_to_tm() in include/linux/rtc.h.
>
> ie something like:
> #ifdef CONFIG_RTC_LIB
> struct rtc_time rtc_ktime_to_tm(ktime_t kt);
> #else
> static inline rtc_time rtc_ktime_to_tm(ktime_t kt)
> {
>     struct rt_time ret;
>     memset(&ret, 0,  sizeof(struct rt_time));
>     return ret;
> }
> #endif

Make sense. Thanks.

>
> thanks
> -john
>
> thanks
> -john



-- 
Baolin.wang
Best Regards