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perf record: Set PERF_FORMAT_LOST by default

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As we want to see the number of lost samples in the perf report, set the
LOST format when it configs evsel.  On old kernels, it'd fallback to
disable it.

Reviewed-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220901195739.668604-3-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Namhyung Kim 2022-09-01 12:57:36 -07:00 committed by Arnaldo Carvalho de Melo
parent a8d68cc457
commit e17f343c3b
2 changed files with 10 additions and 1 deletions
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10
tools/perf/util/evsel.c
View File

@ -1161,6 +1161,7 @@ void evsel__config(struct evsel *evsel, struct record_opts *opts,
attr->sample_id_all = perf_missing_features.sample_id_all ? 0 : 1;
attr->inherit = !opts->no_inherit;
attr->write_backward = opts->overwrite ? 1 : 0;
attr->read_format = PERF_FORMAT_LOST;
evsel__set_sample_bit(evsel, IP);
evsel__set_sample_bit(evsel, TID);
@ -1856,6 +1857,8 @@ static int __evsel__prepare_open(struct evsel *evsel, struct perf_cpu_map *cpus,
static void evsel__disable_missing_features(struct evsel *evsel)
{
if (perf_missing_features.read_lost)
evsel->core.attr.read_format &= ~PERF_FORMAT_LOST;
if (perf_missing_features.weight_struct) {
evsel__set_sample_bit(evsel, WEIGHT);
evsel__reset_sample_bit(evsel, WEIGHT_STRUCT);
@ -1907,7 +1910,12 @@ bool evsel__detect_missing_features(struct evsel *evsel)
* Must probe features in the order they were added to the
* perf_event_attr interface.
*/
if (!perf_missing_features.weight_struct &&
if (!perf_missing_features.read_lost &&
(evsel->core.attr.read_format & PERF_FORMAT_LOST)) {
perf_missing_features.read_lost = true;
pr_debug2("switching off PERF_FORMAT_LOST support\n");
return true;
} else if (!perf_missing_features.weight_struct &&
(evsel->core.attr.sample_type & PERF_SAMPLE_WEIGHT_STRUCT)) {
perf_missing_features.weight_struct = true;
pr_debug2("switching off weight struct support\n");

1
tools/perf/util/evsel.h
View File

@ -188,6 +188,7 @@ struct perf_missing_features {
bool data_page_size;
bool code_page_size;
bool weight_struct;
bool read_lost;
};
extern struct perf_missing_features perf_missing_features;