[lttng-dev] Strange result from LTTng porting to ARM

[J Lin]

Hello Daniel,

I should correct myself and say cross compiled LTTng to run on ARM. We
installed lttng-modules via insmod and verified with lsmod. Regarding
lttng-modules, there was a problem compiling where duplicate definition
occurred. We use kernel version 3.8 and in the source code saw the
conflicting section "should be" guarded for version less than 3.15. So we
added version check to work around it.

We have not tested ust yet. But have compiled all three (lttng-ust,
lttng-tools, lttng-modules) and placed on development board. Right now, we
are just doing a simple trace for a certain irq that triggers every 4ms.
This is the most information we got:
[00:01:36.985006316] (+0.001175688) (none) lttng_statedump_interrupt: {
cpu_id = 0 }, { irq = 29, name = "GIC", action = "twd" }

Also noticed this when creating a session:
[ 2][   64.512057] ##### send signal SIG : 10,
lttng-sessiond(373)->lttng(262) __send_signal

Thanks,
MIKE

2014-11-13 3:10 GMT+08:00 Thibault, Daniel <Daniel.Thibault at drdc-rddc.gc.ca>
:

> ----------------------------------------------------------------------
> Date: Wed, 12 Nov 2014 23:26:41 +0800
> From: J Lin <jmlin.jmlin at gmail.com>
>
> > I've recently ported LTTng to ARM and I can't seem to understand what is
> going wrong with my results. I ran a typical session with "lttng
> enable-event -k -a" for test. Here are the observations:
> >
> > 1. only "lttng_xxx (e.g, lttng_statedump_interrupts)" are recorded 2.
> different sessions yield trace on different CPU (the system has 4) but not
> for all 4, just 1 cpu 3. no recorded session span more than 1 second though
> I would run sleep (i.e., 10s) between "start" and "stop"
> >
> > This leads me to believe LTTng might be dependent on something in the
> system that isn't present. This is a customized kernel of a client. It has
> all required configs.
> >
> > If there is a trigger mechanism after running "lttng start", what would
> it be? It seems it grabs items initially then doesn't continue. I read in
> one of the papers that LTTng is architecture dependent. Any help is
> appreciated.
> >
> > Mike
>
>    How exactly did you "port" LTTng to ARM?  As far as I know, you need
> only rebuild it there.  Your symptoms lead me to believe you may have not
> installed the requisite lttng-modules.  Did you test user-space tracing?
>
> Daniel U. Thibault
> Protection des systèmes et contremesures (PSC) | Systems Protection &
> Countermeasures (SPC)
> Cyber sécurité pour les missions essentielles (CME) | Mission Critical
> Cyber Security (MCCS)
> RDDC - Centre de recherches de Valcartier | DRDC - Valcartier Research
> Centre
> 2459 route de la Bravoure
> Québec QC  G3J 1X5
> CANADA
> Vox : (418) 844-4000 x4245
> Fax : (418) 844-4538
> NAC : 918V QSDJ <http://www.travelgis.com/map.asp?addr=918V%20QSDJ>
> Gouvernement du Canada | Government of Canada
> <http://www.valcartier.drdc-rddc.gc.ca/>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.lttng.org/pipermail/lttng-dev/attachments/20141113/54a5218e/attachment.html>