From mboxrd@z Thu Jan 1 00:00:00 1970 From: compudj@krystal.dyndns.org (Mathieu Desnoyers) Date: Sat, 19 Jun 2010 11:50:54 -0400 Subject: [ltt-dev] Problems on usage of markers in combination with tracepoint probes In-Reply-To: References: Message-ID: <20100619155054.GB22882@Krystal> * jerome zh (jeromezhr at gmail.com) wrote: > Hi Mathieu, > > I did some read on the paper of lttng project, especially your Ph.D thesis. > I have got some questions: > > 1. Why and when should the marker be used in combination with tracepoint probes? LTTng is not aware of tracepoints at the moment. So a marker "declaration" is required to declare the event type and fields. A tracepoint probe needs to be connected on the tracepoint to write the event data into the trace stream. See ltt/ltt-type-serializer.c for details. > 2. If I want to insert tracepoints in kernel files, such as > net/ipv4/ip_input.c, can I implement the tracepoints as module? > Since samples given in samples/tracepoint do NOT show this. The tracepoint itself must be inserted into the kernel code. The tracepoint probes, alongside with marker type declaration, must go into ltt/probes/, which are basically kernel modules. Thanks, Mathieu > > -- > Regards, > > Jerome > > _______________________________________________ > ltt-dev mailing list > ltt-dev at lists.casi.polymtl.ca > http://lists.casi.polymtl.ca/cgi-bin/mailman/listinfo/ltt-dev > -- Mathieu Desnoyers Operating System Efficiency R&D Consultant EfficiOS Inc. http://www.efficios.com