perf stat: Factor out prefix display

The prefix is needed for interval mode to print timestamp at the
beginning of each line.  But the it's tricky for the metric only
mode since it doesn't print every evsel and combines the metrics
into a single line.

So it needed to pass 'first' argument to print_counter_aggrdata()
to determine if the current event is being printed at first.  This
makes the code hard to read.

Let's move the logic out of the function and do it in the outer
print loop.  This would enable further cleanups later.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Athira Jajeev <atrajeev@linux.vnet.ibm.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: James Clark <james.clark@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Xing Zhengjun <zhengjun.xing@linux.intel.com>
Link: https://lore.kernel.org/r/20221114230227.1255976-17-namhyung@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/stat-display.c

@@ -805,8 +805,7 @@ static void uniquify_counter(struct perf_stat_config *config, struct evsel *coun
 
 static void print_counter_aggrdata(struct perf_stat_config *config,
 				   struct evsel *counter, int s,
-				   char *prefix, bool metric_only,
-				   bool *first)
+				   char *prefix, bool metric_only)
 {
 	FILE *output = config->output;
 	u64 ena, run, val;
@@ -825,10 +824,6 @@ static void print_counter_aggrdata(struct perf_stat_config *config,
 	ena = aggr->counts.ena;
 	run = aggr->counts.run;
 
-	if (*first && metric_only) {
-		*first = false;
-		aggr_printout(config, counter, id, aggr->nr);
-	}
 	if (prefix && !metric_only)
 		fprintf(output, "%s", prefix);
 
@@ -849,7 +844,6 @@ static void print_aggr(struct perf_stat_config *config,
 	FILE *output = config->output;
 	struct evsel *counter;
 	int s;
-	bool first;
 
 	if (!config->aggr_map || !config->aggr_get_id)
 		return;
@@ -860,21 +854,23 @@ static void print_aggr(struct perf_stat_config *config,
 	 */
 	for (s = 0; s < config->aggr_map->nr; s++) {
 		if (metric_only) {
+			struct perf_stat_aggr *aggr;
+			struct aggr_cpu_id id = config->aggr_map->map[s];
+
 			if (prefix)
 				fprintf(output, "%s", prefix);
-			else if (config->summary && !config->no_csv_summary &&
-				 config->csv_output && !config->interval)
-				fprintf(output, "%16s%s", "summary", config->csv_sep);
+
+			counter = evlist__first(evlist);
+			aggr = &counter->stats->aggr[s];
+			aggr_printout(config, counter, id, aggr->nr);
 		}
 
-		first = true;
 		evlist__for_each_entry(evlist, counter) {
 			if (counter->merged_stat)
 				continue;
 
-			print_counter_aggrdata(config, counter, s,
-					       prefix, metric_only,
-					       &first);
+			print_counter_aggrdata(config, counter, s, prefix,
+					       metric_only);
 		}
 		if (metric_only)
 			fputc('\n', output);
@@ -885,7 +881,6 @@ static void print_counter(struct perf_stat_config *config,
 			  struct evsel *counter, char *prefix)
 {
 	bool metric_only = config->metric_only;
-	bool first = false;
 	int s;
 
 	/* AGGR_THREAD doesn't have config->aggr_get_id */
@@ -896,9 +891,8 @@ static void print_counter(struct perf_stat_config *config,
 		return;
 
 	for (s = 0; s < config->aggr_map->nr; s++) {
-		print_counter_aggrdata(config, counter, s,
-				       prefix, metric_only,
-				       &first);
+		print_counter_aggrdata(config, counter, s, prefix,
+				       metric_only);
 	}
 }
 
@@ -1260,7 +1254,6 @@ static void print_percore(struct perf_stat_config *config,
 	FILE *output = config->output;
 	struct cpu_aggr_map *core_map;
 	int s, c, i;
-	bool first = true;
 
 	if (!config->aggr_map || !config->aggr_get_id)
 		return;
@@ -1288,11 +1281,7 @@ static void print_percore(struct perf_stat_config *config,
 		if (found)
 			continue;
 
-		if (prefix && metric_only)
-			fprintf(output, "%s", prefix);
-
-		print_counter_aggrdata(config, counter, s,
-				       prefix, metric_only, &first);
+		print_counter_aggrdata(config, counter, s, prefix, metric_only);
 
 		core_map->map[c++] = core_id;
 	}
@@ -1319,10 +1308,6 @@ void evlist__print_counters(struct evlist *evlist, struct perf_stat_config *conf
 	}
 
 	print_header(config, _target, evlist, argc, argv);
-	if (metric_only) {
-		if (config->aggr_mode == AGGR_GLOBAL && prefix && !config->iostat_run)
-			fprintf(config->output, "%s", prefix);
-	}
 
 	switch (config->aggr_mode) {
 	case AGGR_CORE:
@@ -1337,6 +1322,8 @@ void evlist__print_counters(struct evlist *evlist, struct perf_stat_config *conf
 			iostat_print_counters(evlist, config, ts, prefix = buf,
 					      print_counter);
 		else {
+			if (prefix && metric_only)
+				fprintf(config->output, "%s", prefix);
 			evlist__for_each_entry(evlist, counter) {
 				print_counter(config, counter, prefix);
 			}