In this context, timeless refers to the trace data rather than the perf event data. But when detecting whether there are timestamps in the trace data or not, the presence of a timestamp flag on any perf event is used.
Since commit f42c0ce573df ("perf record: Always get text_poke events with --kcore option") timestamps were added to a tracking event when --kcore is used which breaks this detection mechanism. Fix it by detecting if trace timestamps exist by looking at the ETM config flags. This would have always been a more accurate way of doing it anyway.
This fixes the following error message when using --kcore with Coresight:
$ perf record --kcore -e cs_etm// --per-thread $ perf report The perf.data/data data has no samples!
Fixes: f42c0ce573df ("perf record: Always get text_poke events with --kcore option") Reported-by: Yang Shi shy828301@gmail.com Link: https://lore.kernel.org/lkml/CAHbLzkrJQTrYBtPkf=jf3OpQ-yBcJe7XkvQstX9j2frz4W... Signed-off-by: James Clark james.clark@arm.com --- tools/perf/util/cs-etm.c | 30 ++++++++++++++++++------------ 1 file changed, 18 insertions(+), 12 deletions(-)
diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c index 8dd81ddd9e4e..50593289d53c 100644 --- a/tools/perf/util/cs-etm.c +++ b/tools/perf/util/cs-etm.c @@ -2684,26 +2684,29 @@ static int cs_etm__process_auxtrace_event(struct perf_session *session, return 0; }
-static bool cs_etm__is_timeless_decoding(struct cs_etm_auxtrace *etm) +static int cs_etm__setup_timeless_decoding(struct cs_etm_auxtrace *etm) { struct evsel *evsel; struct evlist *evlist = etm->session->evlist; - bool timeless_decoding = true;
/* Override timeless mode with user input from --itrace=Z */ - if (etm->synth_opts.timeless_decoding) - return true; + if (etm->synth_opts.timeless_decoding) { + etm->timeless_decoding = true; + return 0; + }
/* - * Circle through the list of event and complain if we find one - * with the time bit set. + * Find the cs_etm evsel and look at what its timestamp setting was */ - evlist__for_each_entry(evlist, evsel) { - if ((evsel->core.attr.sample_type & PERF_SAMPLE_TIME)) - timeless_decoding = false; - } + evlist__for_each_entry(evlist, evsel) + if (cs_etm__evsel_is_auxtrace(etm->session, evsel)) { + etm->timeless_decoding = + !(evsel->core.attr.config & BIT(ETM_OPT_TS)); + return 0; + }
- return timeless_decoding; + pr_err("CS ETM: Couldn't find ETM evsel\n"); + return -EINVAL; }
/* @@ -3155,7 +3158,6 @@ int cs_etm__process_auxtrace_info_full(union perf_event *event, etm->snapshot_mode = (ptr[CS_ETM_SNAPSHOT] != 0); etm->metadata = metadata; etm->auxtrace_type = auxtrace_info->type; - etm->timeless_decoding = cs_etm__is_timeless_decoding(etm);
/* Use virtual timestamps if all ETMs report ts_source = 1 */ etm->has_virtual_ts = cs_etm__has_virtual_ts(metadata, num_cpu); @@ -3172,6 +3174,10 @@ int cs_etm__process_auxtrace_info_full(union perf_event *event, etm->auxtrace.evsel_is_auxtrace = cs_etm__evsel_is_auxtrace; session->auxtrace = &etm->auxtrace;
+ err = cs_etm__setup_timeless_decoding(etm); + if (err) + return err; + etm->unknown_thread = thread__new(999999999, 999999999); if (!etm->unknown_thread) { err = -ENOMEM;