Re: [PATCH 1/2] perf: tools: cs-etm: Fix print issue for Coresight debug in ETE/TRBE trace

[Mike Leach]

Hi Leo,

On 3/13/26 14:42, Leo Yan wrote:
> On Fri, Mar 13, 2026 at 01:21:28PM +0000, Mike Leach wrote:
> > Building perf with CORESIGHT=1 and the optional CSTRACE_RAW=1 enables
> > additional debug printing of raw trace data when using command:-
> > perf report --dump.
> >
> > This raw trace prints the CoreSight formatted trace frames, which may be
> > used to investigate suspected issues with trace quality / corruption /
> > decode.
> >
> > These frames are not present in ETE + TRBE trace.
> > This fix removes the unnecessary call to print these frames.
> >
> > Due to an addtional fault with the OpenCSD library, this call when ETE/TRBE
> > are being decoded will cause a segfault in perf. This fix also prevents
> > that problem for perf using older (<= 1.8.0 version) OpenCSD libraries.
>
> Thanks for patches!
>
> > Fixes: 68ffe3902898 ("perf tools: Add decoder mechanic to support dumping trace data")
>
> Redundant empty line.

OK

> > Reported-by: Leo Yan <leo.yan@xxxxxxx>
> > Signed-off-by: Mike Leach <mike.leach@xxxxxxx>
> > ---
> >   tools/perf/util/cs-etm-decoder/cs-etm-decoder.c | 3 ++-
> >   1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
> > index 3050fe212666..f7e89693cf16 100644
> > --- a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
> > +++ b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
> > @@ -739,7 +739,8 @@ cs_etm_decoder__new(int decoders, struct cs_etm_decoder_params *d_params,
> >   		goto err_free_decoder;
> >   
> >   	/* init raw frame logging if required */
> > -	cs_etm_decoder__init_raw_frame_logging(d_params, decoder);
> > +	if (format == OCSD_TRC_SRC_FRAME_FORMATTED)
> > +		cs_etm_decoder__init_raw_frame_logging(d_params, decoder);
>
> Could we improve a bit to add checking in
> cs_etm_decoder__init_raw_frame_logging(), something like:
>
>   cs_etm_decoder__init_raw_frame_logging(struct cs_etm_decoder_params *d_params,
>                                         struct cs_etm_decoder *decoder)
>   {
> +       /* No formatted trace frames */
> +       if (!d_params->formatted)
> +               return;
>
> Sorry I should have mentioned this early.

Looking at cs_etm_decoder__init_raw_frame_logging(), this function is 
called once, after cs_etm_decoder__init_def_logger_printing(), and 
unnecessarily repeats a bunch of init calls that are done in that 
function. The one call needed to set up the extra logging could be 
folded into cs_etm_decoder__init_def_logger_printing() with the cond 
compile and d_params checks, removing init_raw_frame_logging() completely

I'll spin up a v2 with this simplification.

Regards

Mike

> >   
> >   	for (i = 0; i < decoders; i++) {
> >   		ret = cs_etm_decoder__create_etm_decoder(d_params,
> > --
> > 2.43.0