Patch "perf stat: Fix --metric-only --json output" has been added to the 6.1-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    perf stat: Fix --metric-only --json output

to the 6.1-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     perf-stat-fix-metric-only-json-output.patch
and it can be found in the queue-6.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit e41f5e063a4edae9d4d4f17ecf9e761f911b7a2b
Author: Namhyung Kim <namhyung@xxxxxxxxxx>
Date:   Mon Nov 7 13:33:10 2022 -0800

    perf stat: Fix --metric-only --json output
    
    [ Upstream commit fdc7d6082459aa6705dd39b827214f6cfc1fa054 ]
    
    Currently it prints all metric headers for JSON output.  But actually it
    skips some metrics with valid_only_metric().  So the output looks like:
    
      $ perf stat --metric-only --json true
      {"unit" : "CPUs utilized", "unit" : "/sec", "unit" : "/sec", "unit" : "/sec", "unit" : "GHz", "unit" : "insn per cycle", "unit" : "/sec", "unit" : "branch-misses of all branches"}
      {"metric-value" : "3.861"}{"metric-value" : "0.79"}{"metric-value" : "3.04"}
    
    As you can see there are 8 units in the header but only 3 metric-values
    are there.  It should skip the unused headers as well.  Also each unit
    should be printed as a separate object like metric values.
    
    With this patch:
    
      $ perf stat --metric-only --json true
      {"unit" : "GHz"}{"unit" : "insn per cycle"}{"unit" : "branch-misses of all branches"}
      {"metric-value" : "4.166"}{"metric-value" : "0.73"}{"metric-value" : "2.96"}
    
    Fixes: df936cadfb58ba93 ("perf stat: Add JSON output option")
    Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
    Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
    Cc: Claire Jensen <cjense@xxxxxxxxxx>
    Cc: Ian Rogers <irogers@xxxxxxxxxx>
    Cc: Ingo Molnar <mingo@xxxxxxxxxx>
    Cc: James Clark <james.clark@xxxxxxx>
    Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
    Cc: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
    Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
    Cc: Xing Zhengjun <zhengjun.xing@xxxxxxxxxxxxxxx>
    Link: https://lore.kernel.org/r/20221107213314.3239159-6-namhyung@xxxxxxxxxx
    Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/tools/perf/util/stat-display.c b/tools/perf/util/stat-display.c
index 8e99818cf023..3023f3993ed5 100644
--- a/tools/perf/util/stat-display.c
+++ b/tools/perf/util/stat-display.c
@@ -430,12 +430,12 @@ static void print_metric_header(struct perf_stat_config *config,
 	    os->evsel->priv != os->evsel->evlist->selected->priv)
 		return;
 
-	if (!valid_only_metric(unit) && !config->json_output)
+	if (!valid_only_metric(unit))
 		return;
 	unit = fixunit(tbuf, os->evsel, unit);
 
 	if (config->json_output)
-		fprintf(os->fh, "\"unit\" : \"%s\"", unit);
+		fprintf(os->fh, "{\"unit\" : \"%s\"}", unit);
 	else if (config->csv_output)
 		fprintf(os->fh, "%s%s", unit, config->csv_sep);
 	else
@@ -847,10 +847,6 @@ static void print_metric_headers(struct perf_stat_config *config,
 		.new_line = new_line_metric,
 		.force_header = true,
 	};
-	bool first = true;
-
-	if (config->json_output && !config->interval)
-		fprintf(config->output, "{");
 
 	if (prefix && !config->json_output)
 		fprintf(config->output, "%s", prefix);
@@ -871,18 +867,12 @@ static void print_metric_headers(struct perf_stat_config *config,
 	evlist__for_each_entry(evlist, counter) {
 		os.evsel = counter;
 
-		if (!first && config->json_output)
-			fprintf(config->output, ", ");
-		first = false;
-
 		perf_stat__print_shadow_stats(config, counter, 0,
 					      0,
 					      &out,
 					      &config->metric_events,
 					      &rt_stat);
 	}
-	if (config->json_output)
-		fprintf(config->output, "}");
 	fputc('\n', config->output);
 }
 
@@ -954,14 +944,8 @@ static void print_interval(struct perf_stat_config *config,
 		}
 	}
 
-	if ((num_print_interval == 0 || config->interval_clear)
-			 && metric_only && !config->json_output)
+	if ((num_print_interval == 0 || config->interval_clear) && metric_only)
 		print_metric_headers(config, evlist, " ", true);
-	if ((num_print_interval == 0 || config->interval_clear)
-			 && metric_only && config->json_output) {
-		fprintf(output, "{");
-		print_metric_headers(config, evlist, " ", true);
-	}
 	if (++num_print_interval == 25)
 		num_print_interval = 0;
 }