[lttng-dev] Fwd: Using Babeltrace to write CTF for MPI application

[Rocky Dunlap]

Apologies... I meant to reply to the list.


---------- Forwarded message ----------
From: Rocky Dunlap <rsdunlapiv at gmail.com>
Date: Wed, Apr 5, 2017 at 10:13 AM
Subject: Re: [lttng-dev] Using Babeltrace to write CTF for MPI application
To: Jonathan Rajotte Julien <Jonathan.rajotte-julien at efficios.com>


Jonathan,

I started with barectf and I really like it!  It works great for basic
cases.  Unfortunately, it only supports simple event structures right now,
so for this reason I switched to the babeltrace CTF library, which has full
support for CTF.

Rocky

On Tue, Apr 4, 2017 at 5:52 PM, Jonathan Rajotte Julien <
Jonathan.rajotte-julien at efficios.com> wrote:

> Hi Rocky,
>
> Not sure if pertinent but did you take a look at the barectf [1] project?
>
> Cheers
>
> [1] https://github.com/efficios/barectf
>
> On 2017-04-04 05:29 PM, Rocky Dunlap wrote:
> > I am instrumenting an MPI application to output a custom application
> trace in CTF using Babeltrace 1.5.2.  I would like to end up with a single
> trace with multiple streams, one per process.  All streams share the same
> stream class (and metadata). All processes have access to the same file
> system.  I am using the C CTF writer API using this test as an example:
> > https://github.com/efficios/babeltrace/blob/stable-1.5/tests
> /lib/test_ctf_writer.c
> >
> > What I have in mind is something like this: process 0 would be
> responsible for writing the metadata and its own stream, while all other
> processes would only need to write their own stream.
> >
> > The issue I have run into is that the individual stream file names are
> determined by appending stream->id to the stream filename and the stream id
> is determined behind the scenes as stream->id =
> stream_class->next_stream_id++.  Since each process has its own address
> space, all processes want stream id of 0.
> >
> > Is there a way using the current API to explicitly set the stream id so
> that each process will write to a separate file?
> >
> > I'm also open for suggestions on the overall approach.  The main reason
> to have each process as a separate stream in a single trace is so that I
> can open the entire trace in an analysis tool like TraceCompass and see all
> processes together.
> >
> > Rocky
> >
> >
> > _______________________________________________
> > lttng-dev mailing list
> > lttng-dev at lists.lttng.org
> > https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
> >
>
> --
> Jonathan R. Julien
> Efficios
> _______________________________________________
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>
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