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 <[e-mail]>
Acked-by: Andi Kleen <[e-mail]>
Acked-by: Jiri Olsa <[e-mail]>
Tested-by: Arnaldo Carvalho de Melo <[e-mail]>
Cc: Alexander Shishkin <[e-mail]>
Cc: Jin Yao <[e-mail]>
Cc: Kan Liang <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Link: http://lore.kernel.org/lkml/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/Documentation/perf-stat.txt

···
 --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

···
 	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)
 {
···
 		    "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

···
 	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

···
 		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

···
 	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;
···
 };
 
 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);