----- On Feb 20, 2019, at 9:10 AM, Mosleh Uddin <mosleh1...@gmail.com> wrote:
> Hello, > Here is what I do to get the consistent behavior: > When the app is running as a service, lttng list -u does not display any > events, > initially I do have to lttng enable-events and lttng start to see the > tracepoints in lttng view. However, after lttng start, I can disable all > events > and I can still see the events coming through in lttng view. When I run the > app > normally, lttng list -u displays the tracepoints I place in the app, and all > functionality of lttng works as expected. > I apologize, I am in the process of trying to get you the outputs you are > asking > for, however due to confidentiality with the app the outputs of running the > commands need to be reviewed by others. I will try to get this to you as soon > as I can. > I can say the service is being kick started by systemd. Also I believe the app > is mass-closing file descriptors when it is daemonizing. I tried to > dynamically > load the liblttng-ust-fd.so but the behavior did not change. Did you load both liblttng-ust-fork.so and liblttng-ust-fd.so with LD_PRELOAD when launching your application ? If not using LD_PRELOAD env. var., how did you load them ? Thanks, Mathieu > Thanks, > Mosleh > On Tue, Feb 19, 2019 at 5:16 PM Francis Deslauriers < [ > mailto:francis.deslauri...@efficios.com | francis.deslauri...@efficios.com ] > > wrote: >> Hi Mosleh, >> Just to be clear: >> When you run your app as a service (background), lttng list -u doesn't >> display any events AND you see events in the live session without >> having run enable-event and start commands. >> When you run your app normally, lttng list -u displays events AND you >> only see events after running enable-event and start commands. >> Is that correct? >> Please provide the output of the lttng-sessiond in verbose mode using >> the following command: >> > lttng-sessiond -vvv >> please provide the output of your application as a service with this >> environment variable: LTTNG_UST_DEBUG=1 >> and please provide us with the service file describing how your >> service is started. >> Put all of this on a [ http://pastebin.com/ | pastebin.com ] >> Is your application mass-closing file descriptors when it's >> daemonizing? how about using fork() syscall without an exec() after >> it? If so, have a look at this part of the UST man page: >> [ https://lttng.org/man/3/lttng-ust/v2.10/#doc-_using_lttng_ust_with_daemons >> | >> https://lttng.org/man/3/lttng-ust/v2.10/#doc-_using_lttng_ust_with_daemons ] >> Thank you, >> Francis >> Le mar. 19 févr. 2019, à 16 h 37, Mosleh Uddin < [ >> mailto:mosleh1...@gmail.com | >> mosleh1...@gmail.com ] > a écrit : >> > Hello, >>> Sorry for the late reply. I was able to figure out the weird behavior from >>> the >>> application. Turns out if I run my application as a service, lttng no longer >> > can see any of the UST tracepoints and causes the behavior I was >> > explaining. >>> When I execute the application normally (./app_name), the functionality is >>> as >>> expected. Is this the expected behavior? Is there some way I can trace the >> > userspace application while running it as a service simultaneously? >> > Thanks for any info, >> > Mosleh >>> On Fri, Feb 15, 2019 at 2:48 PM Francis Deslauriers < [ >>> mailto:francis.deslauri...@efficios.com | francis.deslauri...@efficios.com >>> ] > >> > wrote: >> >> Can you start the lttng-sessiond in verbose mode using the following >> >> command: >> >> > lttng-sessiond -vvv >>>> and then do the lttng create, start of application and lttng view on >>>> another >> >> console. >>>> Then copy the output of the sessiond on [ https://pastebin.com/ | >> >> https://pastebin.com/ ] and send us the link. >> >> Thank you, >> >> Francis >>>> Le ven. 15 févr. 2019, à 14 h 36, Mosleh Uddin < [ >>>> mailto:mosleh1...@gmail.com | >> >> mosleh1...@gmail.com ] > a écrit : >> >>> That's correct, I don't enable any events or do: lttng start. >>>>> Here is some snapshots of starting everything up, followed by starting my >> >>> application. >> >>> Here are the outputs for the commands: >>>>> Note that even though the session is inactive, when a trace event occurs >>>>> in my >> >>> application it is being recorded in the appropriate directory: >>>>> Also maybe important, the system has root only user. Would having the >>>>> application belonging to a different user and trying to run as root cause >>>>> these >>>>> kinds of complications? I did notice when testing on a raspberry pi that >>>>> running an application as a root user would mean running sessions as root >>>>> user >> >>> as well. >> >>> Thanks, >> >>> Mosleh >>>>> On Fri, Feb 15, 2019 at 11:55 AM Francis Deslauriers < [ >>>>> mailto:francis.deslauri...@efficios.com | >>>>> francis.deslauri...@efficios.com ] > >> >>> wrote: >> >>>> Adding back lttng-dev mailing list. >> >>>> So you don't even run a lttng-enable-event command? >> >>>> That's odd. >> >>>> Can you send us the output of the following commands: >> >>>> Is it possible that there are other lttng-sessiond daemons running on >> >>>> the machine? >> >>>> > ps aux | grep "lttng-sessiond" >> >>>> Verify if there are other active tracing sessions: >> >>>> > lttng list >> >>>> Check the details of the current session: >> >>>> > lttng status >> >>>> Thank you, >> >>>> Francis >>>>>> Le ven. 15 févr. 2019, à 11 h 29, Mosleh Uddin < [ >>>>>> mailto:mosleh1...@gmail.com | >> >>>> mosleh1...@gmail.com ] > a écrit : >> >>>> > Hi Francis, >> >>>> > Thank you for the quick response. >> >>>> > Just to clear things up, my application is running when I run that >> >>>> > command. >> >>>> > The commands I am running are: >> >>>> > > lttng-sessiond -d >> >>>> > > lttng create my-sess --live >> >>>> > After this command I start my application. If I then do the command: >> >>>> > > lttng view >>>>>> > I will see the tracepoints in the application in the terminal even >>>>>> > though I have >> >>>> > not done: lttng start. >>>>>> > I thought it was strange that I cannot find my application in the: >>>>>> > lttng list >> >>>> > command under any domain. >>>>>> > Also the reason I start my application after creating a session is >>>>>> > because the >> >>>> > system automatically starts the application using systemd, >>>>>> > in order to get tracing data at all I have to manually stop the >>>>>> > application and >> >>>> > start it again after creating a session. >> >>>> > Thanks again for any help, >> >>>> > Mosleh >>>>>> > On Fri, Feb 15, 2019 at 10:32 AM Francis Deslauriers < [ >>>>>> > mailto:francis.deslauri...@efficios.com | >>>>>> > francis.deslauri...@efficios.com ] > >> >>>> > wrote: >> >>>> >> Hi Mosleh, >> >>>> >> It's expected to not see any event when running lttng list -u if no >> >>>> >> lttng-ust instrumented applications are running. >> >>>> >> What are the exact lttng commands you are running to see those >> >>>> >> unexpected events? >> >>>> >> Thank you, >> >>>> >> Francis >>>>>> >> Le ven. 15 févr. 2019, à 10 h 08, Mosleh Uddin < [ >>>>>> >> mailto:mosleh1...@gmail.com | >> >>>> >> mosleh1...@gmail.com ] > a écrit : >> >>>> >> > Hello, >>>>>> >> > I am having a strange issue with my current application. For some >>>>>> >> > context, I >>>>>> >> > have integrated LTTng into a Yocto build and put custom trace >>>>>> >> > points in my >>>>>> >> > embedded system application. Once I load the built image onto my >>>>>> >> > system and >>>>>> >> > start a session daemon, I try to list all available userspace >>>>>> >> > events (using >> >>>> >> > lttng list -u), but no events show up. >>>>>> >> > The strange occurrence is when I create a session (lltng create >>>>>> >> > my-sess) and not >>>>>> >> > start tracing the trace events will display on the screen >>>>>> >> > regardless (when >>>>>> >> > starting session in live mode with lttng view). I was wondering if >>>>>> >> > anyone has >> >>>> >> > any insight on this issue I am having. >> >>>> >> > Thanks for any assistance, >> >>>> >> > Mosleh >> >>>> >> > _______________________________________________ >> >>>> >> > lttng-dev mailing list >> >>>> >> > [ mailto:lttng-dev@lists.lttng.org | lttng-dev@lists.lttng.org ] >>>>>> >> > [ https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev | >> >>>> >> > https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev ] >> >>>> >> -- >> >>>> >> Francis Deslauriers >> >>>> >> Computer Engineer >> >>>> >> EfficiOS inc. >> >>>> -- >> >>>> Francis Deslauriers >> >>>> Computer Engineer >> >>>> EfficiOS inc. >> >>> _______________________________________________ >> >>> lttng-dev mailing list >> >>> [ mailto:lttng-dev@lists.lttng.org | lttng-dev@lists.lttng.org ] >>>>> [ https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev | >> >>> https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev ] >> >> -- >> >> Francis Deslauriers >> >> Computer Engineer >> >> EfficiOS inc. >> -- >> Francis Deslauriers >> Computer Engineer >> EfficiOS inc. > _______________________________________________ > lttng-dev mailing list > lttng-dev@lists.lttng.org > https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com
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