Messages in this thread Patch in this message | | | From | Namhyung Kim <> | Subject | [PATCH 3/5] perf record: Read and inject LOST_SAMPLES events | Date | Wed, 31 Aug 2022 14:03:50 -0700 |
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When there are lost samples, it can read the number of PERF_FORMAT_LOST and convert it to PERF_RECORD_LOST_SAMPLES and write to the data file at the end.
Signed-off-by: Namhyung Kim <namhyung@kernel.org> --- tools/perf/builtin-record.c | 60 +++++++++++++++++++++++++++++++++++++ 1 file changed, 60 insertions(+)
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c index bce8c941d558..cb9881543a07 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -10,6 +10,7 @@ #include "util/build-id.h" #include <subcmd/parse-options.h> +#include <internal/xyarray.h> #include "util/parse-events.h" #include "util/config.h" @@ -1852,6 +1853,64 @@ record__switch_output(struct record *rec, bool at_exit) return fd; } +static void __record__read_lost_samples(struct record *rec, struct evsel *evsel, + struct perf_record_lost_samples *lost, + int size, int cpu_idx, int thread_idx) +{ + struct perf_counts_values count; + struct perf_sample_id *sid; + struct perf_sample sample = {}; + + if (perf_evsel__read(&evsel->core, cpu_idx, thread_idx, &count) < 0) { + pr_err("read LOST count failed\n"); + return; + } + + if (count.lost == 0) + return; + + lost->lost = count.lost; + if (evsel->core.ids) { + sid = xyarray__entry(evsel->core.sample_id, cpu_idx, thread_idx); + sample.id = sid->id; + } + + perf_event__synthesize_id_sample((void *)(lost + 1), + evsel->core.attr.sample_type, &sample); + record__write(rec, NULL, lost, size); +} + +static void record__read_lost_samples(struct record *rec) +{ + struct perf_session *session = rec->session; + struct machine *machine = &session->machines.host; + struct perf_record_lost_samples *lost; + struct evsel *evsel; + int size = sizeof(*lost) + machine->id_hdr_size; + + lost = zalloc(size); + lost->header.type = PERF_RECORD_LOST_SAMPLES; + lost->header.size = size; + + evlist__for_each_entry(session->evlist, evsel) { + struct xyarray *xy = evsel->core.sample_id; + + if (xyarray__max_x(evsel->core.fd) != xyarray__max_x(xy) || + xyarray__max_y(evsel->core.fd) != xyarray__max_y(xy)) { + pr_debug("Unmatched FD vs. sample ID: skip reading LOST count\n"); + continue; + } + + for (int x = 0; x < xyarray__max_x(xy); x++) { + for (int y = 0; y < xyarray__max_y(xy); y++) { + __record__read_lost_samples(rec, evsel, lost, + size, x, y); + } + } + } + +} + static volatile int workload_exec_errno; /* @@ -2710,6 +2769,7 @@ static int __cmd_record(struct record *rec, int argc, const char **argv) if (rec->off_cpu) rec->bytes_written += off_cpu_write(rec->session); + record__read_lost_samples(rec); record__synthesize(rec, true); /* this will be recalculated during process_buildids() */ rec->samples = 0; -- 2.37.2.789.g6183377224-goog
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