[PATCH][v6] tools/power turbostat: if --iterations, print for specific count of iterations

[Chen Yu <yu.c.chen@intel.com>]

There's a use case during test to only print specific round of iterations
if --iterations is specified, for example, with this patch applied:

turbostat -i 5 -r 4
will capture 4 samples with 5 seconds interval.

Cc: Len Brown <lenb@kernel.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Artem Bityutskiy <artem.bityutskiy@intel.com>
Cc: Doug Smythies <dsmythies@telus.net>
Cc: linux-pm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Chen Yu <yu.c.chen@intel.com>
---
 tools/power/x86/turbostat/turbostat.8 |  2 ++
 tools/power/x86/turbostat/turbostat.c | 23 ++++++++++++++++++++++-
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/tools/power/x86/turbostat/turbostat.8 b/tools/power/x86/turbostat/turbostat.8
index ccf2a69..7452dc4 100644
--- a/tools/power/x86/turbostat/turbostat.8
+++ b/tools/power/x86/turbostat/turbostat.8
@@ -64,6 +64,8 @@ name as necessary to disambiguate it from others is necessary.  Note that option
 .PP
 \fB--interval seconds\fP overrides the default 5.0 second measurement interval.
 .PP
+\fB--iterations count\fP number of the measurement iterations.
+.PP
 \fB--out output_file\fP turbostat output is written to the specified output_file.
 The file is truncated if it already exists, and it is created if it does not exist.
 .PP
diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c
index bd9c6b3..0220892 100644
--- a/tools/power/x86/turbostat/turbostat.c
+++ b/tools/power/x86/turbostat/turbostat.c
@@ -48,6 +48,7 @@ char *proc_stat = "/proc/stat";
 FILE *outf;
 int *fd_percpu;
 struct timespec interval_ts = {5, 0};
+int iterations;
 unsigned int debug;
 unsigned int quiet;
 unsigned int sums_need_wide_columns;
@@ -470,6 +471,7 @@ void help(void)
 	"		{core | package | j,k,l..m,n-p }\n"
 	"--quiet	skip decoding system configuration header\n"
 	"--interval sec	Override default 5-second measurement interval\n"
+	"--iterations count	number of the measurement iterations\n"
 	"--help		print this help message\n"
 	"--list		list column headers only\n"
 	"--out file	create or truncate \"file\" for all output\n"
@@ -2565,6 +2567,7 @@ void turbostat_loop()
 {
 	int retval;
 	int restarted = 0;
+	int done_iters = 0;
 
 restart:
 	restarted++;
@@ -2581,6 +2584,7 @@ void turbostat_loop()
 		goto restart;
 	}
 	restarted = 0;
+	done_iters = 0;
 	gettimeofday(&tv_even, (struct timezone *)NULL);
 
 	while (1) {
@@ -2607,6 +2611,10 @@ void turbostat_loop()
 		compute_average(EVEN_COUNTERS);
 		format_all_counters(EVEN_COUNTERS);
 		flush_output_stdout();
+
+		if (iterations && ++done_iters >= iterations)
+			break;
+
 		nanosleep(&interval_ts, NULL);
 		if (snapshot_proc_sysfs_files())
 			goto restart;
@@ -2626,6 +2634,9 @@ void turbostat_loop()
 		compute_average(ODD_COUNTERS);
 		format_all_counters(ODD_COUNTERS);
 		flush_output_stdout();
+
+		if (iterations && ++done_iters >= iterations)
+			break;
 	}
 }
 
@@ -4999,6 +5010,7 @@ void cmdline(int argc, char **argv)
 		{"Dump",	no_argument,		0, 'D'},
 		{"debug",	no_argument,		0, 'd'},	/* internal, not documented */
 		{"interval",	required_argument,	0, 'i'},
+		{"iterations",	required_argument,	0, 'r'},
 		{"help",	no_argument,		0, 'h'},
 		{"hide",	required_argument,	0, 'H'},	// meh, -h taken by --help
 		{"Joules",	no_argument,		0, 'J'},
@@ -5014,7 +5026,7 @@ void cmdline(int argc, char **argv)
 
 	progname = argv[0];
 
-	while ((opt = getopt_long_only(argc, argv, "+C:c:Ddhi:JM:m:o:qST:v",
+	while ((opt = getopt_long_only(argc, argv, "+C:c:Ddhi:JM:m:o:qr:ST:v",
 				long_options, &option_index)) != -1) {
 		switch (opt) {
 		case 'a':
@@ -5063,6 +5075,15 @@ void cmdline(int argc, char **argv)
 		case 'q':
 			quiet = 1;
 			break;
+		case 'r':
+			iterations = strtod(optarg, NULL);
+
+			if (iterations <= 0) {
+				fprintf(outf, "iterations %d should be positive number\n",
+					iterations);
+				exit(2);
+			}
+			break;
 		case 's':
 			parse_show_hide(optarg, SHOW_LIST);
 			break;
-- 
2.7.4