perf stat: Remove empty new_line_metric function

JIRA: https://issues.redhat.com/browse/RHEL-77935

upstream
========
commit d226f43
Author: James Clark <james.clark@linaro.org>
Date: Tue Nov 12 16:00:43 2024 +0000

description
===========
Despite the name new_line_metric doesn't make a new line, it actually
does nothing. Change it to NULL to avoid confusion.

    Signed-off-by: James Clark <james.clark@linaro.org>
    Tested-by: Ian Rogers <irogers@google.com>
    Cc: Adrian Hunter <adrian.hunter@intel.com>
    Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
    Cc: Ingo Molnar <mingo@redhat.com>
    Cc: Jiri Olsa <jolsa@kernel.org>
    Cc: Kan Liang <kan.liang@linux.intel.com>
    Cc: Mark Rutland <mark.rutland@arm.com>
    Cc: Namhyung Kim <namhyung@kernel.org>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Tim Chen <tim.c.chen@linux.intel.com>
    Cc: Yicong Yang <yangyicong@hisilicon.com>
    Link: https://lore.kernel.org/r/20241112160048.951213-4-james.clark@linaro.org
    Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Signed-off-by: Michael Petlan <mpetlan@redhat.com>

Author: rfmvh

tools/perf/util/stat-display.c

@@ -673,11 +673,6 @@ static void print_metric_only_json(struct perf_stat_config *config __maybe_unuse
 	json_out(os, "\"%s\" : \"%s\"", unit, vals);
 }
 
-static void new_line_metric(struct perf_stat_config *config __maybe_unused,
-			    void *ctx __maybe_unused)
-{
-}
-
 static void print_metric_header(struct perf_stat_config *config,
 				void *ctx,
 				enum metric_threshold_classify thresh __maybe_unused,
@@ -839,16 +834,16 @@ static void printout(struct perf_stat_config *config, struct outstate *os,
 
 	if (config->csv_output) {
 		pm = config->metric_only ? print_metric_only_csv : print_metric_csv;
-		nl = config->metric_only ? new_line_metric : new_line_csv;
+		nl = config->metric_only ? NULL : new_line_csv;
 		pmh = print_metricgroup_header_csv;
 		os->nfields = 4 + (counter->cgrp ? 1 : 0);
 	} else if (config->json_output) {
 		pm = config->metric_only ? print_metric_only_json : print_metric_json;
-		nl = config->metric_only ? new_line_metric : new_line_json;
+		nl = config->metric_only ? NULL : new_line_json;
 		pmh = print_metricgroup_header_json;
 	} else {
 		pm = config->metric_only ? print_metric_only : print_metric_std;
-		nl = config->metric_only ? new_line_metric : new_line_std;
+		nl = config->metric_only ? NULL : new_line_std;
 		pmh = print_metricgroup_header_std;
 	}
 
@@ -1319,7 +1314,7 @@ static void print_metric_headers(struct perf_stat_config *config,
 	struct perf_stat_output_ctx out = {
 		.ctx = &os,
 		.print_metric = print_metric_header,
-		.new_line = new_line_metric,
+		.new_line = NULL,
 		.force_header = true,
 	};
 

tools/perf/util/stat-shadow.c

@@ -327,7 +327,8 @@ static void print_instructions(struct perf_stat_config *config,
 			     "insn per cycle", 0);
 	}
 	if (max_stalled && instructions) {
-		out->new_line(config, ctxp);
+		if (out->new_line)
+			out->new_line(config, ctxp);
 		print_metric(config, ctxp, METRIC_THRESHOLD_UNKNOWN, "%7.2f ",
 			     "stalled cycles per insn", max_stalled / instructions);
 	}
@@ -670,7 +671,7 @@ void *perf_stat__print_shadow_stats_metricgroup(struct perf_stat_config *config,
 			}
 		}
 
-		if ((*num)++ > 0)
+		if ((*num)++ > 0 && out->new_line)
 			out->new_line(config, ctxp);
 		generic_metric(config, mexp, evsel, aggr_idx, out);
 	}