perf stat: Rework header display

There are print_header() and print_interval() to print header lines before
actual counter values.  Also print_metric_headers() needs to be called for
the metric-only case.

Let's move all these logics to a single place including num_print_iv to
refresh the headers for interval mode.
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/20221114230227.1255976-15-namhyung@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/stat-display.c

@@ -1034,19 +1034,14 @@ static void prepare_interval(struct perf_stat_config *config,
 				 ts->tv_sec, ts->tv_nsec);
 }
 
-static void print_interval(struct perf_stat_config *config,
-			   struct evlist *evlist)
+static void print_header_interval_std(struct perf_stat_config *config,
+				      struct target *_target __maybe_unused,
+				      struct evlist *evlist,
+				      int argc __maybe_unused,
+				      const char **argv __maybe_unused)
 {
-	bool metric_only = config->metric_only;
-	unsigned int unit_width = config->unit_width;
 	FILE *output = config->output;
-	static int num_print_interval;
-
-	if (config->interval_clear && isatty(fileno(output)))
-		puts(CONSOLE_CLEAR);
 
-	if ((num_print_interval == 0 || config->interval_clear) &&
-			!config->csv_output && !config->json_output) {
 	switch (config->aggr_mode) {
 	case AGGR_NODE:
 	case AGGR_SOCKET:
@@ -1078,28 +1073,20 @@ static void print_interval(struct perf_stat_config *config,
 		break;
 	}
 
-		if (!metric_only) {
-			fprintf(output, " %*s %*s events\n",
-				COUNTS_LEN, "counts", unit_width, "unit");
-		}
-	}
-
-	if ((num_print_interval == 0 || config->interval_clear) && metric_only)
+	if (config->metric_only)
 		print_metric_headers(config, evlist, " ", true);
-	if (++num_print_interval == 25)
-		num_print_interval = 0;
+	else
+		fprintf(output, " %*s %*s events\n",
+			COUNTS_LEN, "counts", config->unit_width, "unit");
 }
 
-static void print_header(struct perf_stat_config *config,
-			 struct target *_target,
+static void print_header_std(struct perf_stat_config *config,
+			     struct target *_target, struct evlist *evlist,
 			     int argc, const char **argv)
 {
 	FILE *output = config->output;
 	int i;
 
-	fflush(stdout);
-
-	if (!config->csv_output && !config->json_output) {
 	fprintf(output, "\n");
 	fprintf(output, " Performance counter stats for ");
 	if (_target->bpf_str)
@@ -1121,7 +1108,55 @@ static void print_header(struct perf_stat_config *config,
 	if (config->run_count > 1)
 		fprintf(output, " (%d runs)", config->run_count);
 	fprintf(output, ":\n\n");
+
+	if (config->metric_only)
+		print_metric_headers(config, evlist, " ", false);
+}
+
+static void print_header_csv(struct perf_stat_config *config,
+			     struct target *_target __maybe_unused,
+			     struct evlist *evlist,
+			     int argc __maybe_unused,
+			     const char **argv __maybe_unused)
+{
+	if (config->metric_only)
+		print_metric_headers(config, evlist, " ", true);
+}
+static void print_header_json(struct perf_stat_config *config,
+			      struct target *_target __maybe_unused,
+			      struct evlist *evlist,
+			      int argc __maybe_unused,
+			      const char **argv __maybe_unused)
+{
+	if (config->metric_only)
+		print_metric_headers(config, evlist, " ", true);
+}
+
+static void print_header(struct perf_stat_config *config,
+			 struct target *_target,
+			 struct evlist *evlist,
+			 int argc, const char **argv)
+{
+	static int num_print_iv;
+
+	fflush(stdout);
+
+	if (config->interval_clear)
+		puts(CONSOLE_CLEAR);
+
+	if (num_print_iv == 0 || config->interval_clear) {
+		if (config->json_output)
+			print_header_json(config, _target, evlist, argc, argv);
+		else if (config->csv_output)
+			print_header_csv(config, _target, evlist, argc, argv);
+		else if (config->interval)
+			print_header_interval_std(config, _target, evlist, argc, argv);
+		else
+			print_header_std(config, _target, evlist, argc, argv);
 	}
+
+	if (num_print_iv++ == 25)
+		num_print_iv = 0;
 }
 
 static int get_precision(double num)
@@ -1278,18 +1313,10 @@ void evlist__print_counters(struct evlist *evlist, struct perf_stat_config *conf
 	if (interval) {
 		prefix = buf;
 		prepare_interval(config, prefix, ts);
-		print_interval(config, evlist);
-	} else {
-		print_header(config, _target, argc, argv);
 	}
 
+	print_header(config, _target, evlist, argc, argv);
 	if (metric_only) {
-		static int num_print_iv;
-
-		if (num_print_iv == 0 && !interval)
-			print_metric_headers(config, evlist, prefix, false);
-		if (num_print_iv++ == 25)
-			num_print_iv = 0;
 		if (config->aggr_mode == AGGR_GLOBAL && prefix && !config->iostat_run)
 			fprintf(config->output, "%s", prefix);
 	}