On Wed, Apr 03, 2019 at 09:08:45AM -0400, Mosleh Uddin wrote: > Hello, > > Sorry, I should be more specific. I am creating a custom yocto build. I > have seen some examples where systemd is utilized to start the sessiond as > a service. The limitation I have is that I don't want to include the whole > lttng-tools librray in my build. I understand that the sessiond is an
You will have to if you plan on tracing any applications on your resulting image. Why is it a limitation? Size constraint? lttng-tools is already part of OE-core (the meta/ layer). Use this recipe to build it [1] or as a base for a custom one. [1] https://git.yoctoproject.org/cgit/cgit.cgi/poky/tree/meta/recipes-kernel/lttng/lttng-tools_2.10.6.bb You can add the following to your local.conf file to build only lttng-ust and lttng-tools. CORE_IMAGE_EXTRA_INSTALL += "lttng-ust lttng-tools" PACKAGECONFIG_pn-lttng-tools_append = " lttng-ust" By default a systemd service file is installed but is not activated (which seems to be what you want). Cheers > executable, I am just unsure how I could build or get this in my build. > Moving forward from this I could use fork/exec to daemonize which would be > simple. > Is there perhaps a existing recipe? > > Regards, > Mosleh > > On Tue, Apr 2, 2019 at 6:01 PM Mosleh Uddin <mosleh1...@gmail.com> wrote: > > > Hi, > > > > That makes complete sense. I was more curious about the sessiond > > executable. I'm guessing this is something I will have to create along with > > my build? > > > > Regards, > > Mosleh > > > > On Tue, Apr 2, 2019 at 5:18 PM Jonathan Rajotte-Julien < > > jonathan.rajotte-jul...@efficios.com> wrote: > > > >> On Tue, Apr 02, 2019 at 04:54:00PM -0400, Mosleh Uddin wrote: > >> > Hello, > >> > > >> > Could you give me some more insight into spawning my own sessiond? Sorry > >> > I'm not completely clear on the topic. > >> > Thank you for all your assistance. > >> > >> Normally lttng-sessiond is treated as a "server/service/daemon" (think > >> http > >> server as apache) and is *normally* launched as a daemon > >> (systemd/sysVinit) at > >> boot time. > >> > >> Managing manually the lifetime of a lttng-sessiond process is done the > >> same way > >> as any other process. You can manage it via the command line > >> (./lttng-sessiond), via a > >> service manager (systemd/upstart etc.) or with a custom service manager (a > >> python script/c etc.). > >> > >> You could spawn a lttng-sessiond from your application with the > >> appropriate > >> parameters set to isolate it if you need. LTTNG_HOME is an important one. > >> The > >> output directory also can be manipulated. See man lttng-sessiond for more > >> details. You will need to manage the process or leave it to a system > >> administrator and only active tracing when a sessiond is present for > >> example. > >> > >> Cheers > >> > >> > > >> > Regards, > >> > Mosleh > >> > > >> > On Wed, Mar 27, 2019 at 1:52 PM Jonathan Rajotte-Julien < > >> > jonathan.rajotte-jul...@efficios.com> wrote: > >> > > >> > > Hi Mosleh, > >> > > > >> > > On Wed, Mar 27, 2019 at 12:09:54PM -0400, Mosleh Uddin wrote: > >> > > > Hello, > >> > > > > >> > > > Thank you for the quick response. I was able to use the > >> documentation you > >> > > > provided to start a session and get tracepoint list. I do have some > >> > > > follow-up questions: > >> > > > > >> > > > 1) I needed to create a session daemon before executing my custom > >> > > > application. In the API I did see functionality to see if a daemon > >> is > >> > > > active, however, it is possible to spawn a session daemon in my > >> custom > >> > > app? > >> > > > >> > > liblttng-ctl does not expose a lttng-sessiond spawning function since > >> by > >> > > definition it is a daemon executable (think apache,mysql etc.), you > >> will > >> > > have to > >> > > use system/popen/exec.. to spawn the lttng-sessiond process etc. if > >> you > >> > > want to > >> > > control its lifetime using your custom application. > >> > > > >> > > > > >> > > > 2) I am able to get a list of active traces lttng can see in > >> userspace, I > >> > > > enable all the traces and start tracing. The traces however seem to > >> not > >> > > be > >> > > > written anywhere on my filesystem. Do I have to specify a location? > >> Or > >> > > am I > >> > > > missing something? My current flow is: > >> > > > >> > > Please refer to the create command. If outputting locally you will > >> need to > >> > > pass > >> > > a "file://...." url to lttng_create_session. > >> > > > >> > > You can check on the result for each steps using "lttng list" and > >> "lttng > >> > > list > >> > > <session_name>" as you go to troubleshot your setup script. > >> > > > >> > > While debugging you can also start the lttng-sessiond in verbose mode > >> to > >> > > understand what is going on. > >> > > > >> > > Also note that you could also use the lttng "load" api if the session > >> you > >> > > are > >> > > trying to load is "static" and always the same. You would only need to > >> > > ship an > >> > > xml file with your application. > >> > > > >> > > Cheers > >> > > > >> > > > > >> > > > - Creating a session > >> > > > - Specifying the domain > >> > > > - Creating a handle > >> > > > - Creating a channel (with default attributes) > >> > > > - Enabling the channel > >> > > > - Enabling event (for all traces) > >> > > > - Start tracing > >> > > > > >> > > > Thanks again for all the assistance. > >> > > > > >> > > > Regards, > >> > > > Mosleh > >> > > > > >> > > > On Tue, Mar 26, 2019 at 11:29 AM Jonathan Rajotte-Julien < > >> > > > jonathan.rajotte-jul...@efficios.com> wrote: > >> > > > > >> > > > >> > >> -- > >> Jonathan Rajotte-Julien > >> EfficiOS > >> > > -- Jonathan Rajotte-Julien EfficiOS _______________________________________________ lttng-dev mailing list lttng-dev@lists.lttng.org https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
