De : Randy Wijnants [mailto:[email protected]] Envoyé : 27 mai 2014 06:34
> Changed the dashed arrows into dotted arrows. > > Is the arrow running from the lttng session daemon to liblttng-ust valid? > Does the liblttng-ust always write to the shared memory buffer or only if the > session daemon instructs it to (via which interface?) > And what is the interface used between the session and consumer daemon? > > New version: > http://tty32.org/Logging%20configuration2.png<--ESFSECEV-TY3011----------------------------> > > Randy Wijnants. Unless I’m mistaken, when a session daemon disables a channel, for instance, it asks liblttng-ust to turn off the immediate value test in the registered applications (each tracepoint entry is guarded by an immediate value test which is controlled by changing a single byte). That’s the principle, anyway. I haven’t actually followed this through the tangle of LTTng’s code. Rest assured that if liblttng-ust writes to a channel’s buffer, it’s because the event was enabled at the time. I know the consumer daemon(s) read(s) /run/lttng/lttng-session.pid (or $HOME/.lttng/lttng-session.pid) to reach the session daemon. I think the session daemon uses the /run/lttng/ustconsumerd64 (or $HOME/.lttng/ustconsumerd64; 32-bit versions may also exist) socket to send commands to the consumer daemon(s). About the only things the diagram is missing now are: * the lttng-relayd daemon (which completes the “Network destination / streaming” box); * the add-context command (easily put beside enable-channel and enable-event); and * the buffers-global / buffers-pid / buffers-uid alternative (could be put opposite the output TYPE at the Buffer’s top right). Change: * “LTTv” into “LTTV” * “Eclipse” into “Eclipse TMF” * “tracefilesize” into “tracefile-size” * “commandline” into “command line” 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> <http://www.travelgis.com/map.asp?addr=918V%20QSDJ> Gouvernement du Canada | Government of Canada <http://www.valcartier.drdc-rddc.gc.ca/>
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