On 13-09-10 09:20 AM, Thibault, Daniel wrote: > -----Message d'origine----- > From: Julien Desfossez <[email protected]> > > The live trace reading mechanism offers guarantees that the viewer can never > be in a position where it has to assume that it can read the trace safely. > ------------------------------ > > Could you clarify what you mean by that? What does "assuming that the > trace can be read safely" entail that would be bad? There are two risks when reading an active trace : reading a trace without the complete metadata, and assuming a stream is inactive.
If the viewer tries to read a trace for which it does not have the full metadata (which is not known during normal tracing), it risks to crash reading the trace. The live trace reading feature prevents the viewer from getting trace packets if there is new metadata appended between two packets read. Also, if a stream is inactive, usually the viewer would have to wait until it is active again to continue processing the trace. The live trace reading feature informs the viewer that it can safely consider a stream inactive up to a certain point in time. That way, it can continue to process the trace without waiting indefinitely for an inactive stream. The live-timer parameter, configured during the session creation by the user, defines the sending rate of these inactivity beacons. I hope it clarifies the situation. Thanks, Julien > > 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 > _______________________________________________ lttng-dev mailing list [email protected] http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
