perf report: Correct display of samples and events in header

This patch prints the number of samples and the count of performance
events separately.

This allows comparing performance of different applications with each
other.

Previously, the sample count was displayed against an 'Events:' heading.
With this patch, the header now reads (for example):

Samples: 5K of event 'instructions'
Event count (approx.): 2993026545

The patch covers both the stdio and the browser interface.

Signed-off-by: Ashay Rane <ashay.rane@tacc.utexas.edu>
[ committer note: Fixed wrt e7f01d1 ]
Link: http://lkml.kernel.org/n/tip-h4nfjm8msedlk8gxkzivfh5y@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-report.c

@@ -296,12 +296,15 @@ static size_t hists__fprintf_nr_sample_events(struct hists *self,
 {
 	size_t ret;
 	char unit;
-	unsigned long nr_events = self->stats.nr_events[PERF_RECORD_SAMPLE];
+	unsigned long nr_samples = self->stats.nr_events[PERF_RECORD_SAMPLE];
+	u64 nr_events = self->stats.total_period;
 
-	nr_events = convert_unit(nr_events, &unit);
-	ret = fprintf(fp, "# Events: %lu%c", nr_events, unit);
+	nr_samples = convert_unit(nr_samples, &unit);
+	ret = fprintf(fp, "# Samples: %lu%c", nr_samples, unit);
 	if (evname != NULL)
-		ret += fprintf(fp, " %s", evname);
+		ret += fprintf(fp, " of event '%s'", evname);
+
+	ret += fprintf(fp, "\n# Event count (approx.): %lu", nr_events);
 	return ret + fprintf(fp, "\n#\n");
 }
 

tools/perf/util/ui/browsers/hists.c

@@ -840,10 +840,14 @@ static int hists__browser_title(struct hists *self, char *bf, size_t size,
 	int printed;
 	const struct dso *dso = self->dso_filter;
 	const struct thread *thread = self->thread_filter;
-	unsigned long nr_events = self->stats.nr_events[PERF_RECORD_SAMPLE];
+	unsigned long nr_samples = self->stats.nr_events[PERF_RECORD_SAMPLE];
+	u64 nr_events = self->stats.total_period;
+
+	nr_samples = convert_unit(nr_samples, &unit);
+	printed = scnprintf(bf, size,
+			   "Samples: %lu%c of event '%s', Event count (approx.): %lu",
+			   nr_samples, unit, ev_name, nr_events);
 
-	nr_events = convert_unit(nr_events, &unit);
-	printed = scnprintf(bf, size, "Events: %lu%c %s", nr_events, unit, ev_name);
 
 	if (self->uid_filter_str)
 		printed += snprintf(bf + printed, size - printed,