Re: Re: [PATCH 2/3] ftrace: add tracepoint for xtime

[Zhaolei <zhaolei@cn.fujitsu.com>]

Hello, Thomas

I done this patchset to add walltime display for ftrace.
I think it will make ftrace more convenient to use.

To make it work, I rebased a patch from Xiao Guangrong to add tracepoint
into xtime, so I can use this feture for my code.

Could you have a look at this patch?

Thanks
Zhaolei


Steven Rostedt wrote:
> Thomas,
> 
> This patch touches time keeping work. Can I get your ACK on it, or if it 
> belongs to someone else, could you tell me who I need.
> 
> Thanks,
> 
> -- Steve
> 
> 
> On Tue, 25 Aug 2009, Zhaolei wrote:
> 
>> From: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
>>
>> This patch can trace current xtime and wall_to_monotonic. Then user can
>> use ctime() to convert them to wall time which is easier to be understood,
>> especially for flight-recorder which need to get trace event from a kernel
>> dump file.
>>
>> Example of ftrace output:
>>           <idle>-0     [000] 20118.489849: gtod_update_xtime: xtime=1243265589.999999824 wall_to_monotonic=3051713268.744158739
>>            <...>-4020  [001] 20118.489855: sys_open(filename: bf9e66e0, flags: 98800, mode: bf9e66e0)
>>            <...>-4020  [001] 20118.489873: sys_open -> 0xffffffec
>>
>> ctime(1243265590) = date:Mon May 25 11:33:10 2009
>> So we can realize the task with pid 4020 open a file at
>> Mon May 25 11:33:10 2009
>>
>> Changelog:
>> v1->v2: Rebased by Zhao Lei <zhaolei@cn.fujitsu.com>
>>
>> Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
>> Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
>> ---
>>  include/trace/events/xtime.h |   38 ++++++++++++++++++++++++++++++++++++++
>>  kernel/time/ntp.c            |    4 ++++
>>  kernel/time/timekeeping.c    |    6 ++++++
>>  3 files changed, 48 insertions(+), 0 deletions(-)
>>  create mode 100644 include/trace/events/xtime.h
>>
>> diff --git a/include/trace/events/xtime.h b/include/trace/events/xtime.h
>> new file mode 100644
>> index 0000000..398e679
>> --- /dev/null
>> +++ b/include/trace/events/xtime.h
>> @@ -0,0 +1,38 @@
>> +#undef TRACE_SYSTEM
>> +#define TRACE_SYSTEM xtime
>> +
>> +#if !defined(_TRACE_XTIME_H) || defined(TRACE_HEADER_MULTI_READ)
>> +#define _TRACE_XTIME_H
>> +
>> +#include <linux/time.h>
>> +#include <linux/tracepoint.h>
>> +
>> +TRACE_EVENT(gtod_update_xtime,
>> +
>> +	TP_PROTO(struct timespec *xtime, struct timespec *wall_to_monotonic),
>> +
>> +	TP_ARGS(xtime, wall_to_monotonic),
>> +
>> +	TP_STRUCT__entry(
>> +		__field(	long,	xtime_sec		)
>> +		__field(	long,	xtime_nsec		)
>> +		__field(	long,	wall_to_monotonic_sec	)
>> +		__field(	long,	wall_to_monotonic_nsec	)
>> +	),
>> +
>> +	TP_fast_assign(
>> +		__entry->xtime_sec		= xtime->tv_sec;
>> +		__entry->xtime_nsec		= xtime->tv_nsec;
>> +		__entry->wall_to_monotonic_sec	= wall_to_monotonic->tv_sec;
>> +		__entry->wall_to_monotonic_nsec	= wall_to_monotonic->tv_nsec;
>> +	),
>> +
>> +	TP_printk("xtime=%ld.%09ld wall_to_monotonic=%ld.%09ld",
>> +		  __entry->xtime_sec, __entry->xtime_nsec,
>> +		  __entry->wall_to_monotonic_sec, __entry->wall_to_monotonic_nsec)
>> +);
>> +
>> +#endif /* _TRACE_XTIME_H */
>> +
>> +/* This part must be outside protection */
>> +#include <trace/define_trace.h>
>> diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
>> index 4800f93..fc2f13a 100644
>> --- a/kernel/time/ntp.c
>> +++ b/kernel/time/ntp.c
>> @@ -15,6 +15,8 @@
>>  #include <linux/time.h>
>>  #include <linux/mm.h>
>>  
>> +#include <trace/events/xtime.h>
>> +
>>  /*
>>   * NTP timekeeping variables:
>>   */
>> @@ -218,6 +220,8 @@ static enum hrtimer_restart ntp_leap_second(struct hrtimer *timer)
>>  		break;
>>  	}
>>  
>> +	trace_gtod_update_xtime(&xtime, &wall_to_monotonic);
>> +
>>  	write_sequnlock(&xtime_lock);
>>  
>>  	return res;
>> diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
>> index 03cbeb3..2e57a87 100644
>> --- a/kernel/time/timekeeping.c
>> +++ b/kernel/time/timekeeping.c
>> @@ -20,6 +20,9 @@
>>  #include <linux/tick.h>
>>  #include <linux/stop_machine.h>
>>  
>> +#define CREATE_TRACE_POINTS
>> +#include <trace/events/xtime.h>
>> +
>>  /* Structure holding internal timekeeping values. */
>>  struct timekeeper {
>>  	/* Current clocksource used for timekeeping. */
>> @@ -338,6 +341,8 @@ int do_settimeofday(struct timespec *tv)
>>  
>>  	update_vsyscall(&xtime, timekeeper.clock);
>>  
>> +	trace_gtod_update_xtime(&xtime, &wall_to_monotonic);
>> +
>>  	write_sequnlock_irqrestore(&xtime_lock, flags);
>>  
>>  	/* signal hrtimers about time change */
>> @@ -811,6 +816,7 @@ void update_wall_time(void)
>>  
>>  	/* check to see if there is a new clocksource to use */
>>  	update_vsyscall(&xtime, timekeeper.clock);
>> +	trace_gtod_update_xtime(&xtime, &wall_to_monotonic);
>>  }
>>  
>>  /**
>> -- 
>> 1.5.5.3
>>
>>