perf stat: Remove prefix argument in print_metric_headers()

It always passes a whitespace to the function, thus we can just add it to the
function body.  Furthermore, it's only used in the normal output mode.

Well, actually CSV used it but it doesn't need to since we don't care about the
indentation or alignment in the CSV output.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Athira Jajeev <atrajeev@linux.vnet.ibm.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/20221123180208.2068936-6-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/stat-display.c

@@ -996,10 +996,9 @@ static void print_no_aggr_metric(struct perf_stat_config *config,
 }
 
 static void print_metric_headers_std(struct perf_stat_config *config,
-				     const char *prefix, bool no_indent)
+				     bool no_indent)
 {
-	if (prefix)
-		fprintf(config->output, "%s", prefix);
+	fputc(' ', config->output);
 
 	if (!no_indent) {
 		int len = aggr_header_lens[config->aggr_mode];
@@ -1012,28 +1011,23 @@ static void print_metric_headers_std(struct perf_stat_config *config,
 }
 
 static void print_metric_headers_csv(struct perf_stat_config *config,
-				     const char *prefix,
 				     bool no_indent __maybe_unused)
 {
-	if (prefix)
-		fprintf(config->output, "%s", prefix);
 	if (config->interval)
 		fputs("time,", config->output);
 	if (!config->iostat_run)
 		fputs(aggr_header_csv[config->aggr_mode], config->output);
 }
 
 static void print_metric_headers_json(struct perf_stat_config *config,
-				      const char *prefix __maybe_unused,
 				      bool no_indent __maybe_unused)
 {
 	if (config->interval)
 		fputs("{\"unit\" : \"sec\"}", config->output);
 }
 
 static void print_metric_headers(struct perf_stat_config *config,
-				 struct evlist *evlist,
-				 const char *prefix, bool no_indent)
+				 struct evlist *evlist, bool no_indent)
 {
 	struct evsel *counter;
 	struct outstate os = {
@@ -1047,11 +1041,11 @@ static void print_metric_headers(struct perf_stat_config *config,
 	};
 
 	if (config->json_output)
-		print_metric_headers_json(config, prefix, no_indent);
+		print_metric_headers_json(config, no_indent);
 	else if (config->csv_output)
-		print_metric_headers_csv(config, prefix, no_indent);
+		print_metric_headers_csv(config, no_indent);
 	else
-		print_metric_headers_std(config, prefix, no_indent);
+		print_metric_headers_std(config, no_indent);
 
 	if (config->iostat_run)
 		iostat_print_header_prefix(config);
@@ -1132,7 +1126,7 @@ static void print_header_interval_std(struct perf_stat_config *config,
 	}
 
 	if (config->metric_only)
-		print_metric_headers(config, evlist, " ", true);
+		print_metric_headers(config, evlist, true);
 	else
 		fprintf(output, " %*s %*s events\n",
 			COUNTS_LEN, "counts", config->unit_width, "unit");
@@ -1168,7 +1162,7 @@ static void print_header_std(struct perf_stat_config *config,
 	fprintf(output, ":\n\n");
 
 	if (config->metric_only)
-		print_metric_headers(config, evlist, " ", false);
+		print_metric_headers(config, evlist, false);
 }
 
 static void print_header_csv(struct perf_stat_config *config,
@@ -1178,7 +1172,7 @@ static void print_header_csv(struct perf_stat_config *config,
 			     const char **argv __maybe_unused)
 {
 	if (config->metric_only)
-		print_metric_headers(config, evlist, " ", true);
+		print_metric_headers(config, evlist, true);
 }
 static void print_header_json(struct perf_stat_config *config,
 			      struct target *_target __maybe_unused,
@@ -1187,7 +1181,7 @@ static void print_header_json(struct perf_stat_config *config,
 			      const char **argv __maybe_unused)
 {
 	if (config->metric_only)
-		print_metric_headers(config, evlist, " ", true);
+		print_metric_headers(config, evlist, true);
 }
 
 static void print_header(struct perf_stat_config *config,