Re: [PATCH 4/8] perf data: Add a 'perf' prefix to the generic fields

David Ahern
2014-12-11T19:47:35Z

On 12/11/14 11:57 AM, Sebastian Andrzej Siewior wrote:
>>> $ babeltrace ./ctf-data/
>>> [03:19:13.962131936] (+0.000001935) cycles: { }, { perf_ip =
>>> 0xFFFFFFFF8105443A, perf_tid = 20714, perf_pid = 20714, perf_period = 8 }
>>> [03:19:13.962133732] (+0.000001796) cycles: { }, { perf_ip =
>>> 0xFFFFFFFF8105443A, perf_tid = 20714, perf_pid = 20714, perf_period =
>>> 114 }
>>> ...
>>
>> How is babeltrace showing time-of-day for perf-based data files? Is that
>> tod when the command is run?
>
> CTF needs an a base offset which we set to 0 because we don't have it.
> It then takes the NS timestamp and computes the "time".

so the perf-clock timestamp is converted to hour-min-second-nsec. That
is even more confusing - for me at least.

By base offset you mean the conversion between perf-clock and realtime?
What if that information is known (e.g., my tree at
https://github.com/dsahern/linux as time-of-day support through a klm) -
what's the ctf function to set the base offset? Can it be changed as a
file is processed - e.g., tracepoints capturing ntp adjustments?

David