Re: [PATCH v3] perf auxtrace: Add auxtrace_synth_id_range_start() helper

[Adrian Hunter <adrian.hunter@intel.com>]

On 24/10/2025 11:56, tanze wrote:
> To avoid hardcoding the offset value for synthetic event IDs 
> in multiple auxtrace modules (arm-spe, cs-etm, intel-pt, etc.), 
> and to improve code reusability, this patch unifies 
> the handling of the ID offset via a dedicated helper function.
> 
> Signed-off-by: tanze <tanze@kylinos.cn>

Reviewed-by: Adrian Hunter <adrian.hunter@intel.com>

> ---
> 
> Hi Leo Yan, Adrian Hunter,
> 
> Thank you for your valuable comments. I have modified my code according to your suggestions.
> 
> Best regards,
> Ze Tan 
> ---
> Changes in v3: 
>  - Removed PERF_SYNTH_EVENT_ID_OFFSET from synthetic-events.h
>  - Added AUXTRACE_SYNTH_EVENT_ID_OFFSET macro in auxtrace.c
>  - Introduced auxtrace_synth_id_range_start() helper function in auxtrace.c 
>    to unify ID calculation
>  - Updated all auxtrace modules to use the new helper function
> 
> Changes in v2: 
>  - Migrated the macro definitions to the synthetic-events.h file
>  - Added modifications to other source files that use the offset value
> 
> v2:
>  -patch: https://lore.kernel.org/all/20251017021540.45930-1-tanze@kylinos.cn/
> 
> ---
>  tools/perf/util/arm-spe.c        |  5 +----
>  tools/perf/util/auxtrace.c       | 16 ++++++++++++++++
>  tools/perf/util/auxtrace.h       |  1 +
>  tools/perf/util/cs-etm.c         |  5 +----
>  tools/perf/util/intel-bts.c      |  4 +---
>  tools/perf/util/intel-pt.c       |  4 +---
>  tools/perf/util/powerpc-vpadtl.c |  4 +---
>  7 files changed, 22 insertions(+), 17 deletions(-)
> 
> diff --git a/tools/perf/util/arm-spe.c b/tools/perf/util/arm-spe.c
> index 71be979f5077..4fd47600d9e4 100644
> --- a/tools/perf/util/arm-spe.c
> +++ b/tools/perf/util/arm-spe.c
> @@ -1732,10 +1732,7 @@ arm_spe_synth_events(struct arm_spe *spe, struct perf_session *session)
>  	attr.sample_period = spe->synth_opts.period;
>  
>  	/* create new id val to be a fixed offset from evsel id */
> -	id = evsel->core.id[0] + 1000000000;
> -
> -	if (!id)
> -		id = 1;
> +	id = auxtrace_synth_id_range_start(evsel);
>  
>  	if (spe->synth_opts.flc) {
>  		spe->sample_flc = true;
> diff --git a/tools/perf/util/auxtrace.c b/tools/perf/util/auxtrace.c
> index 1539c1dc823c..35f4745f6b2b 100644
> --- a/tools/perf/util/auxtrace.c
> +++ b/tools/perf/util/auxtrace.c
> @@ -62,6 +62,22 @@
>  #include <internal/lib.h>
>  #include "util/sample.h"
>  
> +#define AUXTRACE_SYNTH_EVENT_ID_OFFSET	1000000000ULL
> +
> +/*
> + * Event IDs are allocated sequentially, so a big offset from any
> + * existing ID will reach a unused range.
> + */
> +u64 auxtrace_synth_id_range_start(struct evsel *evsel)
> +{
> +	u64 id = evsel->core.id[0] + AUXTRACE_SYNTH_EVENT_ID_OFFSET;
> +
> +	if (!id)
> +		id = 1;
> +
> +	return id;
> +}
> +
>  /*
>   * Make a group from 'leader' to 'last', requiring that the events were not
>   * already grouped to a different leader.
> diff --git a/tools/perf/util/auxtrace.h b/tools/perf/util/auxtrace.h
> index e0a5b39fed12..ed3a1aaaf5d9 100644
> --- a/tools/perf/util/auxtrace.h
> +++ b/tools/perf/util/auxtrace.h
> @@ -648,6 +648,7 @@ void auxtrace__free_events(struct perf_session *session);
>  void auxtrace__free(struct perf_session *session);
>  bool auxtrace__evsel_is_auxtrace(struct perf_session *session,
>  				 struct evsel *evsel);
> +u64 auxtrace_synth_id_range_start(struct evsel *evsel);
>  
>  #define ITRACE_HELP \
>  "				i[period]:    		synthesize instructions events\n" \
> diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c
> index 30f4bb3e7fa3..62812bef1edf 100644
> --- a/tools/perf/util/cs-etm.c
> +++ b/tools/perf/util/cs-etm.c
> @@ -1726,10 +1726,7 @@ static int cs_etm__synth_events(struct cs_etm_auxtrace *etm,
>  	attr.read_format = evsel->core.attr.read_format;
>  
>  	/* create new id val to be a fixed offset from evsel id */
> -	id = evsel->core.id[0] + 1000000000;
> -
> -	if (!id)
> -		id = 1;
> +	id = auxtrace_synth_id_range_start(evsel);
>  
>  	if (etm->synth_opts.branches) {
>  		attr.config = PERF_COUNT_HW_BRANCH_INSTRUCTIONS;
> diff --git a/tools/perf/util/intel-bts.c b/tools/perf/util/intel-bts.c
> index 3625c6224750..382255393fb3 100644
> --- a/tools/perf/util/intel-bts.c
> +++ b/tools/perf/util/intel-bts.c
> @@ -777,9 +777,7 @@ static int intel_bts_synth_events(struct intel_bts *bts,
>  	attr.sample_id_all = evsel->core.attr.sample_id_all;
>  	attr.read_format = evsel->core.attr.read_format;
>  
> -	id = evsel->core.id[0] + 1000000000;
> -	if (!id)
> -		id = 1;
> +	id = auxtrace_synth_id_range_start(evsel);
>  
>  	if (bts->synth_opts.branches) {
>  		attr.config = PERF_COUNT_HW_BRANCH_INSTRUCTIONS;
> diff --git a/tools/perf/util/intel-pt.c b/tools/perf/util/intel-pt.c
> index 9b1011fe4826..fc9eec8b54b8 100644
> --- a/tools/perf/util/intel-pt.c
> +++ b/tools/perf/util/intel-pt.c
> @@ -3987,9 +3987,7 @@ static int intel_pt_synth_events(struct intel_pt *pt,
>  	attr.sample_id_all = evsel->core.attr.sample_id_all;
>  	attr.read_format = evsel->core.attr.read_format;
>  
> -	id = evsel->core.id[0] + 1000000000;
> -	if (!id)
> -		id = 1;
> +	id = auxtrace_synth_id_range_start(evsel);
>  
>  	if (pt->synth_opts.branches) {
>  		attr.config = PERF_COUNT_HW_BRANCH_INSTRUCTIONS;
> diff --git a/tools/perf/util/powerpc-vpadtl.c b/tools/perf/util/powerpc-vpadtl.c
> index 39a3fb3f1330..bfa4156d7a97 100644
> --- a/tools/perf/util/powerpc-vpadtl.c
> +++ b/tools/perf/util/powerpc-vpadtl.c
> @@ -656,9 +656,7 @@ powerpc_vpadtl_synth_events(struct powerpc_vpadtl *vpa, struct perf_session *ses
>  	attr.config = PERF_SYNTH_POWERPC_VPA_DTL;
>  
>  	/* create new id val to be a fixed offset from evsel id */
> -	id = evsel->core.id[0] + 1000000000;
> -	if (!id)
> -		id = 1;
> +	id = auxtrace_synth_id_range_start(evsel);
>  
>  	err = perf_session__deliver_synth_attr_event(session, &attr, id);
>  	if (err)