---------------------------------------- > Date: Sun, 15 Dec 2013 17:49:40 -0500 > From: [email protected] > To: [email protected] > CC: [email protected] > Subject: Re: [lttng-dev] Viewing existing kernel tracepoints with LTTng > > Le 2013-12-15 09:39, Amit Schreiber a écrit : >> Hi, >> >> I started integrating LTTng into my code, and thought that existing >> tracepoints (which are visible with perf) will be immediately visible to >> LTTng. I obviously misunderstood or am doing something wrong. >> >> What's the correct way to have existing perf tracepoints seen by LTTng? > > LTTng adds probes to existing tracepoints in the kernel. Under the hood, > LTTng probe modules call tracepoint_probe_register() to add a callback > when the tracepoint is enabled. You can thus hook to any tracepoint > defined in the kernel, provided that the probe function have the right > signature. In the case of LTTng, the probe writes an event in the ring > buffer. > > To make things safer and add type checking at compile-time, LTTng > defines the probe code with macros. In fact, all the module's probe code > is generated. Each tracepoint in the kernel must also have an LTTng > probe to be listed, and this is the proper way to do it. For the detail, > refer to the "probe" directory of lttng-modules. > > Cheers, > > Francis >
Thanks a lot, Francis. I appreciate the help and quick response. Amit _______________________________________________ lttng-dev mailing list [email protected] http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
