[lttng-dev] [RELEASE] LTTng-tools 2.1.0-rc1

Wed Aug 22 10:27:55 EDT 2012

Hi David

thanks for your answers. See below for more information.

\Bernd

On 08/22/2012 09:22 AM, David Goulet wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA512
>
> Hi Bernd,
>
> Comments below.
>
> Bernd Hufmann:
>> Hi David
>>
>> I've just installed LTTng-tools 2.1.0-rc1 and I wanted to use it
>> with the Eclipse LTTng tracer control. First, I added 2.1.x as
>> supported version to Eclipse and then I tried to used it with 2.0.x
>> features. I noticed a few differences in the output strings of
>> command outputs [1] as well as the directory structure of generated
>> traces [2]. The Eclipse LTTng tracer control parses the String
>> output of the commands to extract relevant information.
>>
>> Generally, it would be much easier to maintain the Eclipse LTTng
>> tracer control if for existing features the string outputs and the
>> directory structure are the same as before. Please note, if someone
>> uses scripts to generate traces the output format is also
>> important.
>>
>> [1] Command output of lttng create mysession: In v2.0.x the output
>> was: Session mysession created. Traces will be written in
>> /home/user/lttng-traces/mysession-20120314-132824
>>
>> in v2.1.x the output is: Trace(s) output set to
>> /home/user/lttng-traces/mysession-20120822-082243 Session mysession
>> created.
>>
>> So, the first and second line are swapped. Also the content of the
>> line with the path is changed. Would it be possible, to have the
>> same order of the lines and same output as in v2.0.x?
> Hmmmm, that's a fair point. Normally I would *strongly* recommand you
> use "lttng list mysession" to get the output path but still, we could
> make the argument that the output of the "create" command should not
> changed between minor version.
I use the list command to get the directory of a session and the session 
name. However, there are some validation done after "lttng create 
session" (e.g. check for correct session name or path). So the order of 
lines and string content is important. I already use regular expressions 
to problems with minor changes (e.g. more whitespaces), but we cannot 
foresee all cases.

As I understand the numbering scheme, the first digit is for major 
changes (non-backwards compatible, API breaking changes). The second 
digit is for non-API breaking changes including feature and API 
additions. And the last digit (minor) is for bugfixes. Since there is no 
remote protocol defined for using LTTng tools remotely, the Eclipse 
LTTng control relies on the string output of the command line tool. So, 
I consider the output as part of the API :-).

>> [2] Trace directory structure: I noticed that the UST traces are
>> moved under another sub-directory.
>>
>> In v2.0.x the directory structure looked as follows:
>> /home/user/lttng-traces/ |-mysession-20120314-132824 |-kernel
>> |---<kernel trace files>  |-ust |---<programA-<PID>-<date>>
>> |-----------<program A specific trace files>
>>
>> In v2.1.x the directory structure looked as follows:
>> /home/user/lttng-traces/ |-mysession-20120314-132824 |-kernel
>> |---<kernel trace files>  |-ust |--- mysession-20120314-132824
>> |---<programA-<PID>-<date>>  |-----------<program A specific trace
>> files>
> This is absolutely not suppose to be like that... I'm unable to
> reproduce this behavior having the "mysession-**" created two times.
>
> Can you give me the exact series of command you do to get this
> directory structure?
See below the log of commands I executed. I also added the output of 
command "find ." under lttng-traces directory. In there you see the 
additional sub-directory.
By the way, I installed lttng-tools, lttng-ust and userspace-rcu from 
source code.  Here are the corresponding SHA numbers:
lttng-tools: 68264071f9d1b789de1350cbec479b52a9b54acf
lttng-ust: 0f4eaec3e738fa0f33296a46fe08266a60787c23
userspace-rcu: 768fba83676f49eb73fd1d8ad452016a84c5ec2a

 > lttng create mysession
Trace(s) output set to /home/bernd/lttng-traces/mysession-20120822-094418
Session mysession created.

 > lttng enable-event  -a  -k
All kernel events are enabled in channel channel0

 > lttng enable-event  -a  -u
All UST events are enabled in channel channel0

 > lttng start
Tracing started for session mysession

 > lttng stop
Tracing stopped for session mysession

 > lttng destroy
Session mysession destroyed

 > find .
.
./mysession-20120822-094418
./mysession-20120822-094418/mysession-20120822-094542
./mysession-20120822-094418/mysession-20120822-094542/ust
./mysession-20120822-094418/mysession-20120822-094542/ust/lt-hello-2039-20120822-094551
./mysession-20120822-094418/mysession-20120822-094542/ust/lt-hello-2039-20120822-094551/channel0_0
./mysession-20120822-094418/mysession-20120822-094542/ust/lt-hello-2039-20120822-094551/metadata
./mysession-20120822-094418/mysession-20120822-094542/ust/lt-hello-2056-20120822-094551
./mysession-20120822-094418/mysession-20120822-094542/ust/lt-hello-2056-20120822-094551/channel0_0
./mysession-20120822-094418/mysession-20120822-094542/ust/lt-hello-2056-20120822-094551/metadata
./mysession-20120822-094418/kernel
./mysession-20120822-094418/kernel/channel0_0
./mysession-20120822-094418/kernel/metadata

> The normal case and wht 2.1.x should to is provide you the same
> directory structure as 2.0.x. Ex:
>
> ~/lttng-traces/test-20120822-091412/ust/lt-hello-4542-20120822-091415
>
> Thanks!
> David
>
>> So as you see, under ust there is another sub directory with trace
>> session name and date/time. I don't see a practical reason to have
>> this sub directory, because the session name and date/time is
>> already known from the top-level directory. Is it possible to
>> revert this back? In Eclipse I would have to implement a special
>> case for different LTTng-tools versions (in the import dialog).
>>
>> Thank you very much in advance.
>>
>> Best Regards Bernd
>>
>>
>> On 08/17/2012 04:11 PM, David Goulet wrote: Greetings everyone
>> (including LTTng elves),
>>
>> The lttng-tools project provides a session daemon (lttng-sessiond)
>> that acts as a tracing registry, the "lttng" command line for
>> tracing control, a lttng-ctl library for tracing control and a
>> lttng-relayd for network streaming.
>>
>> This is the first release candidate for lttng-tools 2.1 which
>> brings two exciting new features, network streaming and filtering
>> support.
>>
>> It's the combination of a lot of work from the LTTng team so
>> please, to help us improve our tools, report any bugs or
>> misbehaving feature(s) that you may encounter through this mailing
>> list or the bug tracker (https://bugs.lttng.org).
>>
>> - From now on, lttng-tools is in feature freeze mode unless an
>> *IMMENSE* show stopper is found.
>>
>> 2012-08-17 lttng-tools 2.1.0-rc1 * Feature: Network Streaming * Add
>> the lttng-relayd binary for network streaming * Support user space
>> tracer filtering * Multiple fixes
>>
>> Project website: http://lttng.org/lttng2.0 Download link:
>> http://lttng.org/files/lttng-tools/lttng-tools-2.1.0-rc1.tar.bz2
>>
>> Cheers! David
>>> _______________________________________________ lttng-dev mailing
>>> list lttng-dev at lists.lttng.org
>>> http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
>>
>> _______________________________________________ lttng-dev mailing
>> list lttng-dev at lists.lttng.org
>> http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
> -----BEGIN PGP SIGNATURE-----
>
> iQEcBAEBCgAGBQJQNN0vAAoJEELoaioR9I02VxMH/jQkvukB85gPaAiirzf5P2Zo
> 0cudVwdvCuK+43mFUsuN9l7FQh0MKjplWtpqDHDqc1uxgQ7MAGnD+ZzHY347qGVx
> Qdcrn+DBUIeawExfqrqRNZZpiQnKGf4dp0TkQNBHiq72ymVHd3lXCT8NPbrBn8T2
> 9v0FRgLZW29Z/M87I71n5JfPMrg5iU8e8bcNnl1gEL+rCe26Sxb+1MPtmQ3s7XSa
> DYCwYxrWQsCJUxqAfIP4CJQasPiYwPFb3uCyTw5zf6YO+8jpVQOEN5XF6hAsLoWK
> 2XLgDPCFqJAOAXjswykK5SGVw8QuawQQnsQYeG37mxB2lhe29m3JnX4gl1kKwHE=
> =8KxL
> -----END PGP SIGNATURE-----