Messages in this thread | | | Date | Mon, 24 Apr 2023 16:14:38 +0100 | Subject | Re: [PATCH 1/7] perf: cs-etm: Fix timeless decode mode detection | From | Suzuki K Poulose <> |
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On 24/04/2023 14:47, James Clark wrote: > 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-yBcJe7XkvQstX9j2frz4WF-SQ@mail.gmail.com/ > 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)
minor nit: "setup" sound more like prepare to do what is required to do a timeless decoding, while we are doing more like, check if we have to do a timeless decoding. So may be:
cs_etm_check_timeless_decoding() ?
> { > 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)
minor nit: please retain the braces
> + if (cs_etm__evsel_is_auxtrace(etm->session, evsel)) { > + etm->timeless_decoding = > + !(evsel->core.attr.config & BIT(ETM_OPT_TS));
> + return 0; > + }
Otherwise, looks good to me
Suzuki
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