This is a note to let you know that I've just added the patch titled
perf cs-etm: Fix timeless decode mode detection
to the 6.3-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
perf-cs-etm-fix-timeless-decode-mode-detection.patch
and it can be found in the queue-6.3 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit eee3aeeaba43f7be590129766d1c3fc5c8842885
Author: James Clark <james.clark@xxxxxxx>
Date: Mon Apr 24 14:47:41 2023 +0100
perf cs-etm: Fix timeless decode mode detection
[ Upstream commit 449067f3fc9f340da54e383738286881e6634d0b ]
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: f42c0ce573df79d1 ("perf record: Always get text_poke events with --kcore option")
Reported-by: Yang Shi <shy828301@xxxxxxxxx>
Signed-off-by: James Clark <james.clark@xxxxxxx>
Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Ian Rogers <irogers@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: John Garry <john.g.garry@xxxxxxxxxx>
Cc: Leo Yan <leo.yan@xxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
Cc: Mike Leach <mike.leach@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Suzuki Poulouse <suzuki.poulose@xxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Cc: coresight@xxxxxxxxxxxxxxxx
Cc: denik@xxxxxxxxxx
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Link: https://lore.kernel.org/lkml/CAHbLzkrJQTrYBtPkf=jf3OpQ-yBcJe7XkvQstX9j2frz4WF-SQ@xxxxxxxxxxxxxx/
Link: https://lore.kernel.org/r/20230424134748.228137-2-james.clark@xxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c
index f65bac5ddbdb6..e43bc9eea3087 100644
--- a/tools/perf/util/cs-etm.c
+++ b/tools/perf/util/cs-etm.c
@@ -2517,26 +2517,29 @@ 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;
}
/*
@@ -2943,7 +2946,6 @@ 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);
@@ -2960,6 +2962,10 @@ 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;
