perf stat: Align CSV output for summary mode

The 'perf stat' subcommand supports the request for a summary of the
interval counter readings.  But the summary lines break the CSV output
so it's hard for scripts to parse the result.

Before:

  # perf stat -x, -I1000 --interval-count 1 --summary
       1.001323097,8013.48,msec,cpu-clock,8013483384,100.00,8.013,CPUs utilized
       1.001323097,270,,context-switches,8013513297,100.00,0.034,K/sec
       1.001323097,13,,cpu-migrations,8013530032,100.00,0.002,K/sec
       1.001323097,184,,page-faults,8013546992,100.00,0.023,K/sec
       1.001323097,20574191,,cycles,8013551506,100.00,0.003,GHz
       1.001323097,10562267,,instructions,8013564958,100.00,0.51,insn per cycle
       1.001323097,2019244,,branches,8013575673,100.00,0.252,M/sec
       1.001323097,106152,,branch-misses,8013585776,100.00,5.26,of all branches
  8013.48,msec,cpu-clock,8013483384,100.00,7.984,CPUs utilized
  270,,context-switches,8013513297,100.00,0.034,K/sec
  13,,cpu-migrations,8013530032,100.00,0.002,K/sec
  184,,page-faults,8013546992,100.00,0.023,K/sec
  20574191,,cycles,8013551506,100.00,0.003,GHz
  10562267,,instructions,8013564958,100.00,0.51,insn per cycle
  2019244,,branches,8013575673,100.00,0.252,M/sec
  106152,,branch-misses,8013585776,100.00,5.26,of all branches

The summary line loses the timestamp column, which breaks the CSV
output.

We add a column at the original 'timestamp' position and it just says
'summary' for the summary line.

After:

  # perf stat -x, -I1000 --interval-count 1 --summary
       1.001196053,8012.72,msec,cpu-clock,8012722903,100.00,8.013,CPUs utilized
       1.001196053,218,,context-switches,8012753271,100.00,0.027,K/sec
       1.001196053,9,,cpu-migrations,8012769767,100.00,0.001,K/sec
       1.001196053,0,,page-faults,8012786257,100.00,0.000,K/sec
       1.001196053,15004518,,cycles,8012790637,100.00,0.002,GHz
       1.001196053,7954691,,instructions,8012804027,100.00,0.53,insn per cycle
       1.001196053,1590259,,branches,8012814766,100.00,0.198,M/sec
       1.001196053,82601,,branch-misses,8012824365,100.00,5.19,of all branches
           summary,8012.72,msec,cpu-clock,8012722903,100.00,7.986,CPUs utilized
           summary,218,,context-switches,8012753271,100.00,0.027,K/sec
           summary,9,,cpu-migrations,8012769767,100.00,0.001,K/sec
           summary,0,,page-faults,8012786257,100.00,0.000,K/sec
           summary,15004518,,cycles,8012790637,100.00,0.002,GHz
           summary,7954691,,instructions,8012804027,100.00,0.53,insn per cycle
           summary,1590259,,branches,8012814766,100.00,0.198,M/sec
           summary,82601,,branch-misses,8012824365,100.00,5.19,of all branches

Now it's easy for script to analyse the summary lines.

Of course, we also consider not to break possible existing scripts which
can continue to use the broken CSV format by using a new '--no-csv-summary.'
option.

  # perf stat -x, -I1000 --interval-count 1 --summary --no-csv-summary
       1.001213261,8012.67,msec,cpu-clock,8012672327,100.00,8.013,CPUs utilized
       1.001213261,197,,context-switches,8012703742,100.00,24.586,/sec
       1.001213261,9,,cpu-migrations,8012720902,100.00,1.123,/sec
       1.001213261,644,,page-faults,8012738266,100.00,80.373,/sec
       1.001213261,18350698,,cycles,8012744109,100.00,0.002,GHz
       1.001213261,12745021,,instructions,8012759001,100.00,0.69,insn per cycle
       1.001213261,2458033,,branches,8012770864,100.00,306.768,K/sec
       1.001213261,102107,,branch-misses,8012781751,100.00,4.15,of all branches
  8012.67,msec,cpu-clock,8012672327,100.00,7.985,CPUs utilized
  197,,context-switches,8012703742,100.00,24.586,/sec
  9,,cpu-migrations,8012720902,100.00,1.123,/sec
  644,,page-faults,8012738266,100.00,80.373,/sec
  18350698,,cycles,8012744109,100.00,0.002,GHz
  12745021,,instructions,8012759001,100.00,0.69,insn per cycle
  2458033,,branches,8012770864,100.00,306.768,K/sec
  102107,,branch-misses,8012781751,100.00,4.15,of all branches

This option can be enabled in perf config by setting the variable
'stat.no-csv-summary'.

  # perf config stat.no-csv-summary=true

  # perf config -l
  stat.no-csv-summary=true

  # perf stat -x, -I1000 --interval-count 1 --summary
       1.001330198,8013.28,msec,cpu-clock,8013279201,100.00,8.013,CPUs utilized
       1.001330198,205,,context-switches,8013308394,100.00,25.583,/sec
       1.001330198,10,,cpu-migrations,8013324681,100.00,1.248,/sec
       1.001330198,0,,page-faults,8013340926,100.00,0.000,/sec
       1.001330198,8027742,,cycles,8013344503,100.00,0.001,GHz
       1.001330198,2871717,,instructions,8013356501,100.00,0.36,insn per cycle
       1.001330198,553564,,branches,8013366204,100.00,69.081,K/sec
       1.001330198,54021,,branch-misses,8013375952,100.00,9.76,of all branches
  8013.28,msec,cpu-clock,8013279201,100.00,7.985,CPUs utilized
  205,,context-switches,8013308394,100.00,25.583,/sec
  10,,cpu-migrations,8013324681,100.00,1.248,/sec
  0,,page-faults,8013340926,100.00,0.000,/sec
  8027742,,cycles,8013344503,100.00,0.001,GHz
  2871717,,instructions,8013356501,100.00,0.36,insn per cycle
  553564,,branches,8013366204,100.00,69.081,K/sec
  54021,,branch-misses,8013375952,100.00,9.76,of all branches
Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jin Yao <yao.jin@intel.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20210319070156.20394-1-yao.jin@linux.intel.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/Documentation/perf-stat.txt

@@ -482,6 +482,15 @@ convenient for post processing.
 --summary::
 Print summary for interval mode (-I).
 
+--no-csv-summary::
+Don't print 'summary' at the first column for CVS summary output.
+This option must be used with -x and --summary.
+
+This option can be enabled in perf config by setting the variable
+'stat.no-csv-summary'.
+
+$ perf config stat.no-csv-summary=true
+
 EXAMPLES
 --------
 

tools/perf/builtin-stat.c

@@ -1093,6 +1093,11 @@ void perf_stat__set_big_num(int set)
 	stat_config.big_num = (set != 0);
 }
 
+void perf_stat__set_no_csv_summary(int set)
+{
+	stat_config.no_csv_summary = (set != 0);
+}
+
 static int stat__set_big_num(const struct option *opt __maybe_unused,
 			     const char *s __maybe_unused, int unset)
 {
@@ -1249,6 +1254,8 @@ static struct option stat_options[] = {
 		    "threads of same physical core"),
 	OPT_BOOLEAN(0, "summary", &stat_config.summary,
 		       "print summary for interval mode"),
+	OPT_BOOLEAN(0, "no-csv-summary", &stat_config.no_csv_summary,
+		       "don't print 'summary' for CSV summary output"),
 	OPT_BOOLEAN(0, "quiet", &stat_config.quiet,
 			"don't print output (useful with record)"),
 #ifdef HAVE_LIBPFM

tools/perf/util/config.c

@@ -457,6 +457,9 @@ static int perf_stat_config(const char *var, const char *value)
 	if (!strcmp(var, "stat.big-num"))
 		perf_stat__set_big_num(perf_config_bool(var, value));
 
+	if (!strcmp(var, "stat.no-csv-summary"))
+		perf_stat__set_no_csv_summary(perf_config_bool(var, value));
+
 	/* Add other config variables here. */
 	return 0;
 }

tools/perf/util/stat-display.c

@@ -439,6 +439,12 @@ static void printout(struct perf_stat_config *config, struct aggr_cpu_id id, int
 		if (counter->cgrp)
 			os.nfields++;
 	}
+
+	if (!config->no_csv_summary && config->csv_output &&
+	    config->summary && !config->interval) {
+		fprintf(config->output, "%16s%s", "summary", config->csv_sep);
+	}
+
 	if (run == 0 || ena == 0 || counter->counts->scaled == -1) {
 		if (config->metric_only) {
 			pm(config, &os, NULL, "", "", 0);

tools/perf/util/stat.h

@@ -128,6 +128,7 @@ struct perf_stat_config {
 	bool			 all_user;
 	bool			 percore_show_thread;
 	bool			 summary;
+	bool			 no_csv_summary;
 	bool			 metric_no_group;
 	bool			 metric_no_merge;
 	bool			 stop_read_counter;
@@ -160,6 +161,7 @@ struct perf_stat_config {
 };
 
 void perf_stat__set_big_num(int set);
+void perf_stat__set_no_csv_summary(int set);
 
 void update_stats(struct stats *stats, u64 val);
 double avg_stats(struct stats *stats);