On Thu, Mar 20, 2014 at 2:27 PM, Thibault, Daniel <[email protected]> wrote: > LTTNG_HEALTH_APP_MANAGE: > The lttng-health-check function will report the health of the application > command socket manager subsystem. This session daemon thread > (thread_manage_apps) watches the application command sockets; their closure > indicates application shutdown (more accurately, shutdown of the > application's tracepoint provider) and triggers unregistration. > > Would it be correct to say that if this component malfunctions, closure of > application trace files (if tracing in per-process ID mode) will be delayed > until the session is destroyed, but that there won't be any other truly > deleterious consequences? It seems unlikely any events will be lost (the > consumer will commit the buffer contents normally), and this thread failure > would not hamper tracing of other applications nor client-controlled enabling > and disabling of events. The lttng list of event sources would include > ghosts (dead-and-gone apps). Could lttng hang if the client tried to toggle > the enabling of events published by the ghosts? >
It depends on where the "manage apps" thread hangs/dies. Both scenarios are a possibility. The outcome depends largely on whether or not the thread was holding a lock at that time. > I guess my point is that, of all the possible health failures, this seems the > least catastrophic one. > One important thing to understand is that the health check is not an error recovery mechanism; it is only meant as a tool to detect unexpected internal errors from which we can only recover by restarting. Regards, Jérémie > 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/> > > _______________________________________________ > lttng-dev mailing list > [email protected] > http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev -- Jérémie Galarneau EfficiOS Inc. http://www.efficios.com _______________________________________________ lttng-dev mailing list [email protected] http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
