On 13-09-10 12:39 PM, Thibault, Daniel wrote: > Date: Tue, 10 Sep 2013 11:28:53 -0400 > From: Julien Desfossez <[email protected]> > >>> -----Message d'origine----- >>> 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. >>> ------------------------------ >> >> 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. >> >> Julien > > Then maybe what should have been said is: > > The live trace reading mechanism offers guarantees that the viewer can never > be in a position where it cannot read the trace safely. > > Right? Yes, that is especially true for the metadata part, for the inactive streams the viewer could have assumed a stream was terminated.
But yes, in the end, the viewer knows it can read the trace safely. 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
