Re: [diamon-discuss] [BUG] perf data convert to ctf fail.

On Fri, Jan 16, 2015 at 09:14:28AM +0100, Jiri Olsa wrote:
> On Fri, Jan 16, 2015 at 02:55:01AM -0500, Alexandre Montplaisir wrote:
> > Hi Wang,
> > 
> > I can reproduce your issue, using Babeltrace commit 36336d933 (from Jan
> > 6th). I had it working at some point before, so there must have been some
> > changes to the Babeltrace API since then.
> > 
> > If I update to Babeltrace master (9f476966), I then hit
> > https://bugs.lttng.org/issues/874 . Fixing it manually I can get it
> > building, but then the "perf data convert" command now fails with a new
> > error:
> > 
> > perf data convert --to-ctf=./ctf
> > perf: event.c:292: bt_ctf_event_create: Assertion
> > `event_class->stream_class->event_header_type' failed.
> > Aborted
> 
> hum, haven't seen this one before.. I'll check with latest babeltrace
> 
> > 
> > I've CC'ed Mathieu and Jérémie, perhaps they can give us some pointers as to
> > what should be updated in the perf patch set?
> > 
> > Cheers,
> > Alex
> > 
> > 
> > On 2015-01-16 12:23 AM, Wang Nan wrote:
> > >Hi Jiri Olsa,
> > >
> > >We are working on your perf convert to ctf patches and trying to
> > >convert perf.data into CTF trace. By introducing 8 patches from your
> > >repository (the last 8 patches of branch perf/core_ctf_convert) we can
> > >use 'perf data convert --to-ctf' command. However, it doesn't work properly:
> > >
> > >  $ perf record ls
> > >  $ perf data convert --to-ctf ./out.ctf
> > >close: Bad file descriptor
> > >Failed to create CTF stream
> > >[ perf data convert: Converted 'perf.data' into CTF data './out.ctf' ]
> > >[ perf data convert: Converted and wrote 0.000 MB (1 samples) ]
> 

so I've got both errors in the end ;-)

looks like the babeltrace writer API got changed or
were not using it right..

I put some fixes on top of my perf/core_ctf_convert
branch and it's working for me now, but I need to
discuss the API usage

Jérémie,
my babeltrace git sources HEAD is 9f476966aa40.

I needed to do following changes/commits in perf:
(please check my git tree [1] branch perf/core_ctf_convert)

  - perf data: Define custom event_header_type
    define our own event_header_type because it's no longer
    generated by default by the library.. is it correct behaviour?

  - perf data: Disable Werror convert object
    this is probably babeltrace bug, because if I enable -Werror I'll get:

		In file included from /opt/libbabeltrace//include/babeltrace/ctf-writer/stream.h:30:0,
				 from util/data-convert-bt.c:13:
		/opt/libbabeltrace//include/babeltrace/ctf-ir/stream.h:196:12: error: redundant redeclaration of ‘bt_ctf_stream_set_event_context’ [-Werror=redundant-decls]
		 extern int bt_ctf_stream_set_event_context(
			    ^
		/opt/libbabeltrace//include/babeltrace/ctf-ir/stream.h:171:12: note: previous declaration of ‘bt_ctf_stream_set_event_context’ was here
		 extern int bt_ctf_stream_set_event_context(
			    ^

  - perf data: Init stram_class with ID
    the bt_ctf_trace_create_stream function tries to set ID on
    stream_class which gets frozen just few moments ago in
    bt_ctf_stream_create call..

    this trigers failure and close up of stream fd which is not set yet:

        if (close(stream->pos.fd)) {
                perror("close");
        }

    hence the 'close: Bad file descriptor' message
    so this one looks like a bug to me, but we might be misusing the API also..


feel free to move this discussion to babeltrace-devel list ;-)

thanks for comments,
jirka

[1] git://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git