snapshot issue in lttng 2.3.0

snapshot issue in lttng 2.3.0

[Thuya Aung]

Hello lttng-dev,

With lttng 2.3.0 in Ubuntu 12.04 LTS, I only get the tracepoints in kernel folder with snapshot mode. I do not see anything for userspace tracepoints. 
The following is the way I setup for lttng session

lttng create mySession --snapshot

lttng enable-channel kCh --buffers-global --subbuf-size=1048576 -k
lttng enable-event -a -k 

lttng enable-channel uCh --buffers-uid --subbuf-size=1048576 -u
lttng enable-event -a -u

sleep 1
lttng start mySession
sleep 60

lttng snapshot record


lttng stop mySession
lttng destroy mySession

I got the error message saying "Undefined command" with the following

lttng add-output -n myNewOutput file:///home/taung/output (<--- following the examples of man 1 lttng)

Did I do something wrong? What else I should be doing in order to use snapshot feature?

Thanks in advance,
Thuya Aung

Re: snapshot issue in lttng 2.3.0

[Christian Babeux]

Hi Thuya,

> I got the error message saying "Undefined command" with the following
>
> lttng add-output -n myNewOutput file:///home/taung/output (<--- following the examples of man 1 lttng)

There was an error in the man page, the command should be "lttng
snapshot add-output". I've just sent a patch to fix this.

Also you don't need to use add-output/del-output if you want to change
to default snapshot output location. It can be specified with the
create session command and -U option:

lttng create mySession --snapshot -U file:///home/taung/output

[...]

lttng snapshot record -n snapshot_name

Also see doc/snapshot-howto.txt for a complete example.

Thanks,

Christian

On Tue, Sep 24, 2013 at 4:42 PM, Thuya Aung <thuyaaung2002@yahoo.com> wrote:
> Hello lttng-dev,
>
> With lttng 2.3.0 in Ubuntu 12.04 LTS, I only get the tracepoints in kernel folder with snapshot mode. I do not see anything for userspace tracepoints.
> The following is the way I setup for lttng session
>
> lttng create mySession --snapshot
>
> lttng enable-channel kCh --buffers-global --subbuf-size=1048576 -k
> lttng enable-event -a -k
>
> lttng enable-channel uCh --buffers-uid --subbuf-size=1048576 -u
> lttng enable-event -a -u
>
> sleep 1
> lttng start mySession
> sleep 60
>
> lttng snapshot record
>
>
> lttng stop mySession
> lttng destroy mySession
>
> I got the error message saying "Undefined command" with the following
>
> lttng add-output -n myNewOutput file:///home/taung/output (<--- following the examples of man 1 lttng)
>
> Did I do something wrong? What else I should be doing in order to use snapshot feature?
>
> Thanks in advance,
> Thuya Aung
>
> _______________________________________________
> lttng-dev mailing list
> lttng-dev@lists.lttng.org
> http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev

Re: snapshot issue in lttng 2.3.0

[Thibault, Daniel]

Date: Tue, 24 Sep 2013 13:42:44 -0700 (PDT)
From: Thuya Aung <thuyaaung2002@yahoo.com>

> With lttng 2.3.0 in Ubuntu 12.04 LTS, I only get the tracepoints in kernel folder with snapshot mode. I do not see anything for userspace tracepoints. 

   I've tried setting the UST as --buffers-pid, and also running the snapshot without any kernel events.  Same problem: no UST snapshot is produced, EXCEPT when I run UST per-UID without a kernel component.

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)
R & D pour la défense Canada - Valcartier (RDDC Valcartier) | Defence R&D Canada - Valcartier (DRDC Valcartier)
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/>

Re: snapshot issue in lttng 2.3.0

[Thibault, Daniel]

Date: Tue, 24 Sep 2013 13:42:44 -0700 (PDT)
From: Thuya Aung <thuyaaung2002@yahoo.com>

> With lttng 2.3.0 in Ubuntu 12.04 LTS, I only get the tracepoints in kernel folder with snapshot mode. I do not see anything for userspace tracepoints. 
> The following is the way I setup for lttng session
>
> lttng create mySession --snapshot
> lttng enable-channel kCh --buffers-global --subbuf-size=1048576 -k
> lttng enable-event -a -k
> lttng enable-channel uCh --buffers-uid --subbuf-size=1048576 -u
> lttng enable-event -a -u
> sleep 1
> lttng start mySession
> sleep 60
> lttng snapshot record
> lttng stop mySession
> lttng destroy mySession
>
> I got the error message saying "Undefined command" with the following
>
> lttng add-output -n myNewOutput file:///home/taung/output (<--- following the examples of man 1 lttng)
>
> Did I do something wrong? What else I should be doing in order to use snapshot feature?
>
> Thuya Aung

   I can confirm this problem (I ran my usual user-space event generator and got nothing for UST in the snapshot).  Regarding your script, there is one mistake made twice: when you enable-event, you need to specify the channel.  You should have gotten an error ("Error: Events: Non-default channel exists within session").  The correct script lines are:

lttng enable-event -a -k -c kCh
lttng enable-event -a -u -c uCh

   As for the output, the mistake is simple.  The correct line is:

lttng snapshot add-output -n myNewOutput file:///home/taung/output

   add-output is a snapshot action, not an lttng command.  Additionally, because a snapshot output is created by default, you must delete it first (currently there is just one output slot):

lttng snapshot del-output 1
lttng snapshot add-output -n myNewOutput file:///home/taung/output

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)
R & D pour la défense Canada - Valcartier (RDDC Valcartier) | Defence R&D Canada - Valcartier (DRDC Valcartier)
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/>