perf: tools: cs-etm: Fixes for CoreSight debug dump

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

Posted by Mike Leach 3 weeks, 3 days ago

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.

Fixes: 68ffe3902898 ("perf tools: Add decoder mechanic to support dumping trace data")

Reported-by: Leo Yan <leo.yan@arm.com>
Signed-off-by: Mike Leach <mike.leach@arm.com>
---
 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);
 
 	for (i = 0; i < decoders; i++) {
 		ret = cs_etm_decoder__create_etm_decoder(d_params,
-- 
2.43.0

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

Posted by Leo Yan 3 weeks, 3 days ago

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.

> Reported-by: Leo Yan <leo.yan@arm.com>
> Signed-off-by: Mike Leach <mike.leach@arm.com>
> ---
>  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.

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

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

Posted by Mike Leach 2 weeks, 6 days ago

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@arm.com>
>> Signed-off-by: Mike Leach <mike.leach@arm.com>
>> ---
>>   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
>>