rtla/osnoise: Add the automatic trace option

Add the -a/--auto <arg in us> option. This option sets some commonly
used options while debugging the system. It aims to help users produce
reports in the field, reducing the number of arguments passed to the
tool in the first approach to a problem.

It is equivalent to setting osnoise/stop_tracing_us with the argument,
setting tracing_thresh to 1 us, and saving the trace to osnoise_trace.txt
file if the trace is stopped automatically.

Link: https://lkml.kernel.org/r/ef04c961b227eb93a83cd0b54bfca45e1a381b77.1646247211.git.bristot@kernel.org

Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Clark Williams <williams@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

Documentation/tools/rtla/common_osnoise_options.rst

@@ -1,3 +1,8 @@
+**-a**, **--auto** *us*
+
+        Set the automatic trace mode. This mode sets some commonly used options
+        while debugging the system. It is equivalent to use **-s** *us* **-T 1 -t**.
+
 **-p**, **--period** *us*
 
         Set the *osnoise* tracer period in microseconds.

tools/tracing/rtla/src/osnoise_hist.c

@@ -426,11 +426,12 @@ static void osnoise_hist_usage(char *usage)
 
 	static const char * const msg[] = {
 		"",
-		"  usage: rtla osnoise hist [-h] [-D] [-d s] [-p us] [-r us] [-s us] [-S us] [-T us] \\",
-		"	  [-t[=file]] [-c cpu-list] [-P priority] [-b N] [-E N] [--no-header] \\",
+		"  usage: rtla osnoise hist [-h] [-D] [-d s] [-a us] [-p us] [-r us] [-s us] [-S us] \\",
+		"	  [-T us] [-t[=file]] [-c cpu-list] [-P priority] [-b N] [-E N] [--no-header] \\",
 		"	  [--no-summary] [--no-index] [--with-zeros]",
 		"",
 		"	  -h/--help: print this menu",
+		"	  -a/--auto: set automatic trace mode, stopping the session if argument in us sample is hit",
 		"	  -p/--period us: osnoise period in us",
 		"	  -r/--runtime us: osnoise runtime in us",
 		"	  -s/--stop us: stop trace if a single sample is higher than the argument in us",
@@ -487,6 +488,7 @@ static struct osnoise_hist_params
 
 	while (1) {
 		static struct option long_options[] = {
+			{"auto",		required_argument,	0, 'a'},
 			{"bucket-size",		required_argument,	0, 'b'},
 			{"entries",		required_argument,	0, 'E'},
 			{"cpus",		required_argument,	0, 'c'},
@@ -510,14 +512,25 @@ static struct osnoise_hist_params
 		/* getopt_long stores the option index here. */
 		int option_index = 0;
 
-		c = getopt_long(argc, argv, "c:b:d:E:Dhp:P:r:s:S:t::T:0123",
+		c = getopt_long(argc, argv, "a:c:b:d:E:Dhp:P:r:s:S:t::T:0123",
 				 long_options, &option_index);
 
 		/* detect the end of the options. */
 		if (c == -1)
 			break;
 
 		switch (c) {
+		case 'a':
+			/* set sample stop to auto_thresh */
+			params->stop_us = get_llong_from_str(optarg);
+
+			/* set sample threshold to 1 */
+			params->threshold = 1;
+
+			/* set trace */
+			params->trace_output = "osnoise_trace.txt";
+
+			break;
 		case 'b':
 			params->bucket_size = get_llong_from_str(optarg);
 			if ((params->bucket_size == 0) || (params->bucket_size >= 1000000))

tools/tracing/rtla/src/osnoise_top.c

@@ -245,10 +245,11 @@ void osnoise_top_usage(char *usage)
 	int i;
 
 	static const char * const msg[] = {
-		"  usage: rtla osnoise [top] [-h] [-q] [-D] [-d s] [-p us] [-r us] [-s us] [-S us] [-T us] \\",
-		"	  [-t[=file]] [-c cpu-list] [-P priority]",
+		"  usage: rtla osnoise [top] [-h] [-q] [-D] [-d s] [-a us] [-p us] [-r us] [-s us] [-S us] \\",
+		"	  [-T us] [-t[=file]] [-c cpu-list] [-P priority]",
 		"",
 		"	  -h/--help: print this menu",
+		"	  -a/--auto: set automatic trace mode, stopping the session if argument in us sample is hit",
 		"	  -p/--period us: osnoise period in us",
 		"	  -r/--runtime us: osnoise runtime in us",
 		"	  -s/--stop us: stop trace if a single sample is higher than the argument in us",
@@ -294,6 +295,7 @@ struct osnoise_top_params *osnoise_top_parse_args(int argc, char **argv)
 
 	while (1) {
 		static struct option long_options[] = {
+			{"auto",		required_argument,	0, 'a'},
 			{"cpus",		required_argument,	0, 'c'},
 			{"debug",		no_argument,		0, 'D'},
 			{"duration",		required_argument,	0, 'd'},
@@ -312,14 +314,25 @@ struct osnoise_top_params *osnoise_top_parse_args(int argc, char **argv)
 		/* getopt_long stores the option index here. */
 		int option_index = 0;
 
-		c = getopt_long(argc, argv, "c:d:Dhp:P:qr:s:S:t::T:",
+		c = getopt_long(argc, argv, "a:c:d:Dhp:P:qr:s:S:t::T:",
 				 long_options, &option_index);
 
 		/* Detect the end of the options. */
 		if (c == -1)
 			break;
 
 		switch (c) {
+		case 'a':
+			/* set sample stop to auto_thresh */
+			params->stop_us = get_llong_from_str(optarg);
+
+			/* set sample threshold to 1 */
+			params->threshold = 1;
+
+			/* set trace */
+			params->trace_output = "osnoise_trace.txt";
+
+			break;
 		case 'c':
 			retval = parse_cpu_list(optarg, &params->monitored_cpus);
 			if (retval)