----- Original Message ----- > From: "Daniel Thibault" <[email protected]> > To: [email protected] > Sent: Thursday, October 10, 2013 8:33:56 AM > Subject: Re: [lttng-dev] Sub-buffer multiplicity on multi-core systems > > Date: Tue, 8 Oct 2013 17:57:23 -0400 > From: J?r?mie Galarneau <[email protected]> > > > In kernel tracing, ring buffers are separate per CPU, per channel. > > Each ring buffer is flushed into its own CTF data stream file. These > > streams are only "merged" by Babeltrace (or any other reader) while > > reading the trace. > > > > J?r?mie > > Thanks for confirming the 1:1 correspondence between channels and files. > I wanted to make sure I understood the ins and outs properly.
Not quite, It's a 1:1 correspondence between ring buffer and file. 1:N correspondence between channel and ring buffers. (typically, N being the number of cpus) (therefore 1:N correspondence between channel and files) 1:M correspondence between ring buffer and sub-buffers. (M being the number of subbuffers per buffers, configurable on a per-channel basis) 1:1 correspondence between sub-buffer and CTF trace packet. Thanks, Mathieu > > 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 > -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com _______________________________________________ lttng-dev mailing list [email protected] http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
