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From: Philippe Proulx via lttng-dev <>
To: Mathieu Desnoyers <>
Cc: Philippe Proulx <>,
	Jeremie Galarneau <>,
	 rostedt <>,
	lttng-dev <>
Subject: Re: [lttng-dev] Usage example of libbabeltrace (babeltrace2) to read CTF traces from a GUI
Date: Tue, 15 Jun 2021 11:13:41 -0400	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

On Mon, Jun 14, 2021 at 4:01 PM Mathieu Desnoyers via lttng-dev
<> wrote:
> Hi Philippe, Hi Jeremie,
> Steven is interested to use libbabeltrace as a CTF trace reader in the KernelShark
> project. It's a GUI which shows Linux kernel traces.
> He notices that most of the documented usage examples of the libbabeltrace API
> focus on use-cases where a custom trace format is converted into CTF.
> I know that the babeltrace2 program is the main user of libbabeltrace at this
> point, and that it reads CTF as source.
> For using libbabeltrace as CTF reader for a GUI, what would be the best examples
> to look at as starting point ? Perhaps the babeltrace2 binary, or just adapt a
> smaller example program and change the custom trace format source to "ctf.fs" ?
> Or anything else ?


Unfortunately, the Babeltrace 2 C API documentation [1] doesn't offer a
graph building example at the moment.

Therefore, indeed, the "best" example would be the babeltrace2(1) CLI
(see `src/cli`), although I understand that it's a very generic example
which can be overwhelming to explore.

However, note that instead of instantiating an existing sink component
class (as found in a plugin), you'll want to make your own sink
component class to get access to each event message while also
controlling the graph operations. Using
bt_graph_add_simple_sink_component() [2] would be a good start.

I can cook a minimal working example in the following days.



> Thanks,
> Mathieu
> --
> Mathieu Desnoyers
> EfficiOS Inc.
> _______________________________________________
> lttng-dev mailing list
lttng-dev mailing list

  reply	other threads:[~2021-06-15 15:14 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-14 20:00 Mathieu Desnoyers via lttng-dev
2021-06-15 15:13 ` Philippe Proulx via lttng-dev [this message]
2021-06-15 15:57   ` Steven Rostedt via lttng-dev
2021-06-19  3:42     ` Philippe Proulx via lttng-dev

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