tools/power turbostat: Fix and document --header_iterations

The "header_iterations" option is commonly used to de-clutter
the screen of redundant header label rows in an interactive session:
Eg. every 10 rows:

$ sudo turbostat --header_iterations 10 -S -q -i 1

But --header_iterations was missing from turbostat.8

Also turbostat help advertised the "-N" short option
that did not actually work:

$ turbostat --help
  -N, --header_iterations num
		print header every num iterations

Repair "-N"
Document "--header_iterations" on turbostat.8

Signed-off-by: Len Brown <len.brown@intel.com>

Author: lenb

tools/power/x86/turbostat/turbostat.8

@@ -111,12 +111,14 @@ The column name "all" can be used to enable all disabled-by-default built-in cou
 .PP
 \fB--no-perf\fP Disable all the uses of the perf API.
 .PP
-\fB--force\fPForce turbostat to run on an unsupported platform (minimal defaults).
+\fB--force\fP Force turbostat to run on an unsupported platform (minimal defaults).
 .PP
 \fB--interval seconds\fP overrides the default 5.0 second measurement interval.
 .PP
 \fB--num_iterations num\fP number of the measurement iterations.
 .PP
+\fB--header_iterations num\fP print header every num 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

tools/power/x86/turbostat/turbostat.c

@@ -11443,7 +11443,7 @@ void cmdline(int argc, char **argv)
 	 * Parse some options early, because they may make other options invalid,
 	 * like adding the MSR counter with --add and at the same time using --no-msr.
 	 */
-	while ((opt = getopt_long_only(argc, argv, "+MPn:", long_options, &option_index)) != -1) {
+	while ((opt = getopt_long_only(argc, argv, "+:MP", long_options, &option_index)) != -1) {
 		switch (opt) {
 		case 'M':
 			no_msr = 1;
@@ -11457,7 +11457,7 @@ void cmdline(int argc, char **argv)
 	}
 	optind = 0;
 
-	while ((opt = getopt_long_only(argc, argv, "+C:c:Dde:hi:Jn:o:qMST:v", long_options, &option_index)) != -1) {
+	while ((opt = getopt_long_only(argc, argv, "+C:c:Dde:hi:Jn:N:o:qMST:v", long_options, &option_index)) != -1) {
 		switch (opt) {
 		case 'a':
 			parse_add_command(optarg);
@@ -11500,7 +11500,6 @@ void cmdline(int argc, char **argv)
 			}
 			break;
 		case 'h':
-		default:
 			help();
 			exit(1);
 		case 'i':
@@ -11539,19 +11538,15 @@ void cmdline(int argc, char **argv)
 			num_iterations = strtoul(optarg, NULL, 0);
 			errno = 0;
 
-			if (errno || num_iterations == 0) {
-				fprintf(outf, "invalid iteration count: %s\n", optarg);
-				exit(2);
-			}
+			if (errno || num_iterations == 0)
+				errx(-1, "invalid iteration count: %s", optarg);
 			break;
 		case 'N':
 			header_iterations = strtoul(optarg, NULL, 0);
 			errno = 0;
 
-			if (errno || header_iterations == 0) {
-				fprintf(outf, "invalid header iteration count: %s\n", optarg);
-				exit(2);
-			}
+			if (errno || header_iterations == 0)
+				errx(-1, "invalid header iteration count: %s", optarg);
 			break;
 		case 's':
 			/*
@@ -11574,6 +11569,9 @@ void cmdline(int argc, char **argv)
 			print_version();
 			exit(0);
 			break;
+		default:
+			help();
+			exit(1);
 		}
 	}
 }