Commit e3a23261 authored by Namhyung Kim's avatar Namhyung Kim Committed by Arnaldo Carvalho de Melo
Browse files

perf record: Read and inject LOST_SAMPLES events 



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.

Reviewed-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Signed-off-by: default avatarNamhyung 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/20220901195739.668604-4-namhyung@kernel.org


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent e17f343c

tools/perf/builtin-record.c

+64 −0
Original line number Diff line number Diff line
@@ -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 +1853,68 @@ 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 cpu_idx, int thread_idx)

{

	struct perf_counts_values count;

	struct perf_sample_id *sid;

	struct perf_sample sample = {};

	int id_hdr_size;



	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;

	}



	id_hdr_size = perf_event__synthesize_id_sample((void *)(lost + 1),

						       evsel->core.attr.sample_type, &sample);

	lost->header.size = sizeof(*lost) + id_hdr_size;

	record__write(rec, NULL, lost, lost->header.size);

}



static void record__read_lost_samples(struct record *rec)

{

	struct perf_session *session = rec->session;

	struct perf_record_lost_samples *lost;

	struct evsel *evsel;



	lost = zalloc(PERF_SAMPLE_MAX_SIZE);

	if (lost == NULL) {

		pr_debug("Memory allocation failed\n");

		return;

	}



	lost->header.type = PERF_RECORD_LOST_SAMPLES;



	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, x, y);

			}

		}

	}

	free(lost);



}



static volatile int workload_exec_errno;



/*
@@ -2714,6 +2777,7 @@ 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;