-----Message d'origine----- Envoyé : 20 novembre 2013 09:44 > We don't use the timestamps for this. Each packet has a sequence number given > by the producer, and the reader is querying for packets by requesting > sequence numbers > (increasing by one each time). In the case you present here, the reader will > try to query the sequence number of an overwritten packet, and will therefore > not be able to get it. > It will move on to the next packet until it finally finds the first packet > which sequence number matches its current sequence number (or the writer > position).
So my original suggestion holds: performance could increase just a little bit (on the reader side) if the reader's request (lib_ring_buffer_get_subbuf, is it?) did not return -EAGAIN but rather the current "earliest available sequence number" it should next ask for. In the (presumably rare) case where the reader has been passed by the writers by several sub-buffer sequence numbers' worth, this would allow the reader to skip ahead to the next likely-to-succeed sequence number request. Does this make sense? 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
