perf stat: Move common code in print_metric_headers()

The struct perf_stat_output_ctx is set in a loop with the same values.
Move the code out of the loop and keep the loop minimal.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.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/20221107213314.3239159-5-namhyung@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/stat-display.c

@@ -835,11 +835,16 @@ static void print_metric_headers(struct perf_stat_config *config,
 				 struct evlist *evlist,
 				 const char *prefix, bool no_indent)
 {
-	struct perf_stat_output_ctx out;
 	struct evsel *counter;
 	struct outstate os = {
 		.fh = config->output
 	};
+	struct perf_stat_output_ctx out = {
+		.ctx = &os,
+		.print_metric = print_metric_header,
+		.new_line = new_line_metric,
+		.force_header = true,
+	};
 	bool first = true;
 
 	if (config->json_output && !config->interval)
@@ -863,13 +868,11 @@ static void print_metric_headers(struct perf_stat_config *config,
 	/* Print metrics headers only */
 	evlist__for_each_entry(evlist, counter) {
 		os.evsel = counter;
-		out.ctx = &os;
-		out.print_metric = print_metric_header;
+
 		if (!first && config->json_output)
 			fprintf(config->output, ", ");
 		first = false;
-		out.new_line = new_line_metric;
-		out.force_header = true;
+
 		perf_stat__print_shadow_stats(config, counter, 0,
 					      0,
 					      &out,