perf evsel: Know if byte swap is needed

Instead of passing it around for parsing as an explicit parameter, will
help with reading tracepoint fields when not using a perf session or
pevent structure, i.e. for non perf.data centered workflows.

Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-qa67ikv2sm49cwa7dyjhhp6g@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-test.c

@@ -564,7 +564,7 @@ static int test__basic_mmap(void)
 			goto out_munmap;
 		}
 
-		err = perf_evlist__parse_sample(evlist, event, &sample, false);
+		err = perf_evlist__parse_sample(evlist, event, &sample);
 		if (err) {
 			pr_err("Can't parse sample, err = %d\n", err);
 			goto out_munmap;
@@ -781,7 +781,7 @@ static int test__PERF_RECORD(void)
 				if (type < PERF_RECORD_MAX)
 					nr_events[type]++;
 
-				err = perf_evlist__parse_sample(evlist, event, &sample, false);
+				err = perf_evlist__parse_sample(evlist, event, &sample);
 				if (err < 0) {
 					if (verbose)
 						perf_event__fprintf(event, stderr);

tools/perf/builtin-top.c

@@ -823,7 +823,7 @@ static void perf_top__mmap_read_idx(struct perf_top *top, int idx)
 	int ret;
 
 	while ((event = perf_evlist__mmap_read(top->evlist, idx)) != NULL) {
-		ret = perf_evlist__parse_sample(top->evlist, event, &sample, false);
+		ret = perf_evlist__parse_sample(top->evlist, event, &sample);
 		if (ret) {
 			pr_err("Can't parse sample, err = %d\n", ret);
 			continue;

tools/perf/util/evlist.c

@@ -884,10 +884,10 @@ int perf_evlist__start_workload(struct perf_evlist *evlist)
 }
 
 int perf_evlist__parse_sample(struct perf_evlist *evlist, union perf_event *event,
-			      struct perf_sample *sample, bool swapped)
+			      struct perf_sample *sample)
 {
 	struct perf_evsel *evsel = perf_evlist__first(evlist);
-	return perf_evsel__parse_sample(evsel, event, sample, swapped);
+	return perf_evsel__parse_sample(evsel, event, sample);
 }
 
 size_t perf_evlist__fprintf(struct perf_evlist *evlist, FILE *fp)

tools/perf/util/evlist.h

@@ -125,7 +125,7 @@ bool perf_evlist__sample_id_all(struct perf_evlist *evlist);
 u16 perf_evlist__id_hdr_size(struct perf_evlist *evlist);
 
 int perf_evlist__parse_sample(struct perf_evlist *evlist, union perf_event *event,
-			      struct perf_sample *sample, bool swapped);
+			      struct perf_sample *sample);
 
 bool perf_evlist__valid_sample_type(struct perf_evlist *evlist);
 bool perf_evlist__valid_sample_id_all(struct perf_evlist *evlist);

tools/perf/util/evsel.c

@@ -767,11 +767,13 @@ int perf_evsel__open_per_thread(struct perf_evsel *evsel,
 	return __perf_evsel__open(evsel, &empty_cpu_map.map, threads);
 }
 
-static int perf_event__parse_id_sample(const union perf_event *event, u64 type,
-				       struct perf_sample *sample,
-				       bool swapped)
+static int perf_evsel__parse_id_sample(const struct perf_evsel *evsel,
+				       const union perf_event *event,
+				       struct perf_sample *sample)
 {
+	u64 type = evsel->attr.sample_type;
 	const u64 *array = event->sample.array;
+	bool swapped = evsel->needs_swap;
 	union u64_swap u;
 
 	array += ((event->header.size -
@@ -832,10 +834,11 @@ static bool sample_overlap(const union perf_event *event,
 }
 
 int perf_evsel__parse_sample(struct perf_evsel *evsel, union perf_event *event,
-			     struct perf_sample *data, bool swapped)
+			     struct perf_sample *data)
 {
 	u64 type = evsel->attr.sample_type;
 	u64 regs_user = evsel->attr.sample_regs_user;
+	bool swapped = evsel->needs_swap;
 	const u64 *array;
 
 	/*
@@ -852,7 +855,7 @@ int perf_evsel__parse_sample(struct perf_evsel *evsel, union perf_event *event,
 	if (event->header.type != PERF_RECORD_SAMPLE) {
 		if (!evsel->attr.sample_id_all)
 			return 0;
-		return perf_event__parse_id_sample(event, type, data, swapped);
+		return perf_evsel__parse_id_sample(evsel, event, data);
 	}
 
 	array = event->sample.array;

tools/perf/util/evsel.h

@@ -69,6 +69,7 @@ struct perf_evsel {
 	struct cpu_map		*cpus;
 	unsigned int		sample_size;
 	bool 			supported;
+	bool 			needs_swap;
 	/* parse modifier helper */
 	int			exclude_GH;
 	struct perf_evsel	*leader;
@@ -205,7 +206,7 @@ static inline int perf_evsel__read_scaled(struct perf_evsel *evsel,
 void hists__init(struct hists *hists);
 
 int perf_evsel__parse_sample(struct perf_evsel *evsel, union perf_event *event,
-			     struct perf_sample *sample, bool swapped);
+			     struct perf_sample *sample);
 
 static inline struct perf_evsel *perf_evsel__next(struct perf_evsel *evsel)
 {

tools/perf/util/header.c

@@ -1256,8 +1256,10 @@ read_event_desc(struct perf_header *ph, int fd)
 		if (ret != (ssize_t)sizeof(nr))
 			goto error;
 
-		if (ph->needs_swap)
+		if (ph->needs_swap) {
 			nr = bswap_32(nr);
+			evsel->needs_swap = true;
+		}
 
 		evsel->name = do_read_string(fd, ph);
 
@@ -2626,6 +2628,8 @@ int perf_session__read_header(struct perf_session *session, int fd)
 
 		if (evsel == NULL)
 			goto out_delete_evlist;
+
+		evsel->needs_swap = header->needs_swap;
 		/*
 		 * Do it before so that if perf_evsel__alloc_id fails, this
 		 * entry gets purged too at perf_evlist__delete().

tools/perf/util/python.c

@@ -805,7 +805,7 @@ static PyObject *pyrf_evlist__read_on_cpu(struct pyrf_evlist *pevlist,
 		if (pyevent == NULL)
 			return PyErr_NoMemory();
 
-		err = perf_evlist__parse_sample(evlist, event, &pevent->sample, false);
+		err = perf_evlist__parse_sample(evlist, event, &pevent->sample);
 		if (err)
 			return PyErr_Format(PyExc_OSError,
 					    "perf: can't parse sample, err=%d", err);

tools/perf/util/session.c

@@ -722,8 +722,7 @@ static int flush_sample_queue(struct perf_session *s,
 		if (iter->timestamp > limit)
 			break;
 
-		ret = perf_evlist__parse_sample(s->evlist, iter->event, &sample,
-						s->header.needs_swap);
+		ret = perf_evlist__parse_sample(s->evlist, iter->event, &sample);
 		if (ret)
 			pr_err("Can't parse sample, err = %d\n", ret);
 		else {
@@ -1174,8 +1173,7 @@ static int perf_session__process_event(struct perf_session *session,
 	/*
 	 * For all kernel events we get the sample data
 	 */
-	ret = perf_evlist__parse_sample(session->evlist, event, &sample,
-					session->header.needs_swap);
+	ret = perf_evlist__parse_sample(session->evlist, event, &sample);
 	if (ret)
 		return ret;