[lttng-dev] lttng trace format

[Jérémie Galarneau]

On Thu, Feb 20, 2014 at 9:15 PM, Jessica Foest <jessica.foest at gmail.com> wrote:
> Hi all
> is there a document that explain the meaning of fields displayed in the
> traces generated by babeltrace ?
>
>
> an example :
>
> [19:52:06.617756425] (+0.000001667) workstation sys_splice: { cpu_id = 3 },
> { perf_branches = 418157709, perf_branch_instructions = 418156946,
> perf_cache_misses = 6682769, perf_cache_references = 50147680,
> perf_instructions = 3049323811, vppid = 587, ppid = 587, vtid = 3502, tid =
> 3502, vpid = 3499, nice = 0, prio = 20, procname = "lttng-consumerd", pid =
> 3499 }, { fd_in = 10, off_in = 0x0, fd_out = 26, off_out = 0x0, len = 65536,
> flags = 5 }
>
> the field mentioned in blue , is it the execution time of sys_splice ?
>

Hi Jessica,

It represents the delta between this event and the one before.

For instance, picking two events from a kernel trace on my system...

[21:25:29.901647477] (+0.000001585) XThink power_cpu_idle: { cpu_id =
2 }, { state = 4, cpu_id = 2 }
[21:25:29.901648940] (+0.000001463) XThink sched_stat_sleep: { cpu_id
= 6 }, { comm = "clementine", tid = 4318, delay = 5158461 }

901648940 - 901647477 = +0.000001463

Regards,
Jérémie

> if yes , what's the necessity of sys_exit ?
> Regards
>
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-- 
Jérémie Galarneau
EfficiOS Inc.
http://www.efficios.com