[PATCH 4/6] perf: cs-etm: Respect --no-itrace option
Adrian Hunter
adrian.hunter at intel.com
Mon Aug 24 02:53:16 PDT 2026
On 21/08/2026 12:50, James Clark wrote:
> If there is a bug in decoding then Perf will exit early and you can't
> investigate by using the raw dump mode. Make the --no-itrace option stop
> Coresight decoding after printing the aux header so decode errors don't
> stop the rest of the samples being printed.
>
> pmu_type and evsel_is_auxtrace need to be set so that the
> unleader_auxtrace() behavior is the same as without --no-itrace.
>
> Signed-off-by: James Clark <james.clark at linaro.org>
For auxtrace:
Reviewed-by: Adrian Hunter <adrian.hunter at intel.com>
> ---
> tools/perf/util/auxtrace.c | 2 +-
> tools/perf/util/auxtrace.h | 1 +
> tools/perf/util/cs-etm.c | 66 +++++++++++++++++++++++++---------------------
> 3 files changed, 38 insertions(+), 31 deletions(-)
>
> diff --git a/tools/perf/util/auxtrace.c b/tools/perf/util/auxtrace.c
> index e3c770b46e94..caa53056d349 100644
> --- a/tools/perf/util/auxtrace.c
> +++ b/tools/perf/util/auxtrace.c
> @@ -123,7 +123,7 @@ static int evlist__regroup(struct evlist *evlist, struct evsel *leader, struct e
> return 0;
> }
>
> -static bool auxtrace__dont_decode(struct perf_session *session)
> +bool auxtrace__dont_decode(struct perf_session *session)
> {
> return !session->itrace_synth_opts ||
> session->itrace_synth_opts->dont_decode;
> diff --git a/tools/perf/util/auxtrace.h b/tools/perf/util/auxtrace.h
> index 971b817d3396..47fb97136836 100644
> --- a/tools/perf/util/auxtrace.h
> +++ b/tools/perf/util/auxtrace.h
> @@ -651,6 +651,7 @@ 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);
> +bool auxtrace__dont_decode(struct perf_session *session);
>
> #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 dd15e91b7b38..22884c9fdff8 100644
> --- a/tools/perf/util/cs-etm.c
> +++ b/tools/perf/util/cs-etm.c
> @@ -969,7 +969,7 @@ static int cs_etm__flush_events(struct perf_session *session,
> struct cs_etm_auxtrace *etm = container_of(session->auxtrace,
> struct cs_etm_auxtrace,
> auxtrace);
> - if (dump_trace)
> + if (dump_trace || auxtrace__dont_decode(session))
> return 0;
>
> if (!tool->ordered_events)
> @@ -3040,7 +3040,7 @@ static int cs_etm__process_event(struct perf_session *session,
> struct cs_etm_auxtrace,
> auxtrace);
>
> - if (dump_trace)
> + if (dump_trace || auxtrace__dont_decode(session))
> return 0;
>
> if (!tool->ordered_events) {
> @@ -3603,27 +3603,49 @@ int cs_etm__process_auxtrace_info_full(union perf_event *event,
> int err = 0;
> int aux_hw_id_found;
> int i;
> - u64 *ptr = NULL;
> + u64 *ptr = (u64 *) auxtrace_info->priv;
> u64 **metadata = NULL;
>
> - /* First the global part */
> - ptr = (u64 *) auxtrace_info->priv;
> - num_cpu = ptr[CS_PMU_TYPE_CPUS] & 0xffffffff;
> + etm = zalloc(sizeof(*etm));
> + if (!etm)
> + return -ENOMEM;
> +
> + session->auxtrace = &etm->auxtrace;
> + etm->auxtrace.free = cs_etm__free;
> + etm->auxtrace.evsel_is_auxtrace = cs_etm__evsel_is_auxtrace;
> + etm->auxtrace.process_event = cs_etm__process_event;
> + etm->auxtrace.process_auxtrace_event = cs_etm__process_auxtrace_event;
> + etm->auxtrace.flush_events = cs_etm__flush_events;
> + etm->auxtrace.free_events = cs_etm__free_events;
> + etm->pmu_type = (unsigned int) ((ptr[CS_PMU_TYPE_CPUS] >> 32) & 0xffffffff);
> +
> + /*
> + * Don't go further than the minimum required to identify this event as
> + * auxtrace with cs_etm__evsel_is_auxtrace() so unleader_auxtrace()
> + * works.
> + */
> + if (auxtrace__dont_decode(session))
> + return 0;
>
> /*
> * Bound num_cpu by the event size: the global header consumes
> * CS_ETM_HEADER_SIZE bytes, and each CPU needs at least one u64
> * metadata entry after that.
> */
> + num_cpu = ptr[CS_PMU_TYPE_CPUS] & 0xffffffff;
> priv_size = total_size - event_header_size - INFO_HEADER_SIZE -
> CS_ETM_HEADER_SIZE;
> if (num_cpu <= 0 || priv_size <= 0 ||
> - num_cpu > priv_size / (int)sizeof(u64))
> - return -EINVAL;
> + num_cpu > priv_size / (int)sizeof(u64)) {
> + err = -EINVAL;
> + goto err_free_etm;
> + }
>
> metadata = zalloc(sizeof(*metadata) * num_cpu);
> - if (!metadata)
> - return -ENOMEM;
> + if (!metadata) {
> + err = -ENOMEM;
> + goto err_free_etm;
> + }
>
> /* Start parsing after the common part of the header */
> i = CS_HEADER_VERSION_MAX;
> @@ -3682,13 +3704,6 @@ int cs_etm__process_auxtrace_info_full(union perf_event *event,
> goto err_free_metadata;
> }
>
> - etm = zalloc(sizeof(*etm));
> -
> - if (!etm) {
> - err = -ENOMEM;
> - goto err_free_metadata;
> - }
> -
> /*
> * As all the ETMs run at the same exception level, the system should
> * have the same PID format crossing CPUs. So cache the PID format
> @@ -3698,7 +3713,7 @@ int cs_etm__process_auxtrace_info_full(union perf_event *event,
>
> err = auxtrace_queues__init_nr(&etm->queues, max_cpu + 1);
> if (err)
> - goto err_free_etm;
> + goto err_free_metadata;
>
> for (unsigned int j = 0; j < etm->queues.nr_queues; ++j) {
> err = cs_etm__setup_queue(etm, &etm->queues.queue_array[j], j);
> @@ -3736,7 +3751,6 @@ int cs_etm__process_auxtrace_info_full(union perf_event *event,
> etm->session = session;
>
> etm->num_cpu = num_cpu;
> - etm->pmu_type = (unsigned int) ((ptr[CS_PMU_TYPE_CPUS] >> 32) & 0xffffffff);
> etm->snapshot_mode = (ptr[CS_ETM_SNAPSHOT] != 0);
> etm->metadata = metadata;
> etm->auxtrace_type = auxtrace_info->type;
> @@ -3763,14 +3777,6 @@ int cs_etm__process_auxtrace_info_full(union perf_event *event,
> "you can specify the itrace option 'T' for timestamp decoding\n"
> "if the Coresight timestamp on the platform is same with the kernel time.\n\n");
>
> - etm->auxtrace.process_event = cs_etm__process_event;
> - etm->auxtrace.process_auxtrace_event = cs_etm__process_auxtrace_event;
> - etm->auxtrace.flush_events = cs_etm__flush_events;
> - etm->auxtrace.free_events = cs_etm__free_events;
> - etm->auxtrace.free = cs_etm__free;
> - etm->auxtrace.evsel_is_auxtrace = cs_etm__evsel_is_auxtrace;
> - session->auxtrace = &etm->auxtrace;
> -
> cs_etm__setup_timeless_decoding(etm);
>
> etm->tc.time_shift = tc->time_shift;
> @@ -3853,13 +3859,13 @@ int cs_etm__process_auxtrace_info_full(union perf_event *event,
>
> err_free_queues:
> cs_etm__free_queues(etm);
> - session->auxtrace = NULL;
> -err_free_etm:
> - zfree(&etm);
> err_free_metadata:
> /* No need to check @metadata[j], free(NULL) is supported */
> for (int j = 0; j < num_cpu; j++)
> zfree(&metadata[j]);
> zfree(&metadata);
> +err_free_etm:
> + session->auxtrace = NULL;
> + zfree(&etm);
> return err;
> }
>
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