| Message ID | 20230424134748.228137-2-james.clark@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | perf: cs-etm: Fixes around timestamped and timeless decoding | expand |
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
On Mon, Apr 24, 2023 at 8:14 AM Suzuki K Poulose <suzuki.poulose@arm.com> wrote: > > 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() ? > I didn't catch that "setup_timeless_decoding" can be treated as the initialization of the timeless decoding. On the other hand _check_ doesn't imply that it changes the flag. Maybe "_setup_timeless_decoding_flag" will be more specific about its intention? - Denis > > Otherwise, looks good to me > > Suzuki > > > _______________________________________________ > CoreSight mailing list -- coresight@lists.linaro.org > To unsubscribe send an email to coresight-leave@lists.linaro.org
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;
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(-)