rtla: Add --trigger support

Add --trigger option. This option enables a trace event trigger to the
previous -e sys:event argument, allowing some advanced tracing options.

For instance, in a system with CPUs 2:23 isolated, it is possible to get
a stack trace of thread wakeup targeting those CPUs while running
osnoise with the following command line:

 # osnoise top -c 2-23 -a 50 -e sched:sched_wakeup --trigger="stacktrace if target_cpu >= 2"

This option is available for all current tools.

Link: https://lkml.kernel.org/r/07d2983d5f71261d4da89dbaf02efcad100ab8ee.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>

Author: Daniel Bristot de Oliveira

Documentation/tools/rtla/common_options.rst

@@ -18,6 +18,9 @@
 
         Enable an event in the trace (**-t**) session. The argument can be a specific event, e.g., **-e** *sched:sched_switch*, or all events of a system group, e.g., **-e** *sched*. Multiple **-e** are allowed. It is only active when **-t** or **-a** are set.
 
+**--trigger** *<trigger>*
+        Enable a trace event trigger to the previous **-e** *sys:event*. For further information about event trigger see https://www.kernel.org/doc/html/latest/trace/events.html#event-triggers.
+
 **-P**, **--priority** *o:prio|r:prio|f:prio|d:runtime:period*
 
         Set scheduling parameters to the osnoise tracer threads, the format to set the priority are:

tools/tracing/rtla/src/osnoise_hist.c

@@ -428,8 +428,8 @@ static void osnoise_hist_usage(char *usage)
 	static const char * const msg[] = {
 		"",
 		"  usage: rtla osnoise hist [-h] [-D] [-d s] [-a us] [-p us] [-r us] [-s us] [-S us] \\",
-		"	  [-T us] [-t[=file]] [-e sys[:event]] [-c cpu-list] [-P priority] [-b N] [-E N] \\",
-		"	  [--no-header] [--no-summary] [--no-index] [--with-zeros]",
+		"	  [-T us] [-t[=file]] [-e sys[:event]] [--trigger <trigger>] [-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",
@@ -443,6 +443,7 @@ static void osnoise_hist_usage(char *usage)
 		"	  -D/--debug: print debug info",
 		"	  -t/--trace[=file]: save the stopped trace to [file|osnoise_trace.txt]",
 		"	  -e/--event <sys:event>: enable the <sys:event> in the trace instance, multiple -e are allowed",
+		"	     --trigger <trigger>: enable a trace event trigger to the previous -e event",
 		"	  -b/--bucket-size N: set the histogram bucket size (default 1)",
 		"	  -E/--entries N: set the number of entries of the histogram (default 256)",
 		"	     --no-header: do not print header",
@@ -510,13 +511,14 @@ static struct osnoise_hist_params
 			{"no-summary",		no_argument,		0, '1'},
 			{"no-index",		no_argument,		0, '2'},
 			{"with-zeros",		no_argument,		0, '3'},
+			{"trigger",		required_argument,	0, '4'},
 			{0, 0, 0, 0}
 		};
 
 		/* getopt_long stores the option index here. */
 		int option_index = 0;
 
-		c = getopt_long(argc, argv, "a:c:b:d:e:E:Dhp:P:r:s:S:t::T:0123",
+		c = getopt_long(argc, argv, "a:c:b:d:e:E:Dhp:P:r:s:S:t::T:01234:",
 				 long_options, &option_index);
 
 		/* detect the end of the options. */
@@ -619,6 +621,17 @@ static struct osnoise_hist_params
 		case '3': /* with zeros */
 			params->with_zeros = 1;
 			break;
+		case '4': /* trigger */
+			if (params->events) {
+				retval = trace_event_add_trigger(params->events, optarg);
+				if (retval) {
+					err_msg("Error adding trigger %s\n", optarg);
+					exit(EXIT_FAILURE);
+				}
+			} else {
+				osnoise_hist_usage("--trigger requires a previous -e\n");
+			}
+			break;
 		default:
 			osnoise_hist_usage("Invalid option");
 		}

tools/tracing/rtla/src/osnoise_top.c

@@ -247,7 +247,7 @@ void osnoise_top_usage(char *usage)
 
 	static const char * const msg[] = {
 		"  usage: rtla osnoise [top] [-h] [-q] [-D] [-d s] [-a us] [-p us] [-r us] [-s us] [-S us] \\",
-		"	  [-T us] [-t[=file]] [-e sys[:event]] [-c cpu-list] [-P priority]",
+		"	  [-T us] [-t[=file]] [-e sys[:event]] [--trigger <trigger>] [-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",
@@ -261,6 +261,7 @@ void osnoise_top_usage(char *usage)
 		"	  -D/--debug: print debug info",
 		"	  -t/--trace[=file]: save the stopped trace to [file|osnoise_trace.txt]",
 		"	  -e/--event <sys:event>: enable the <sys:event> in the trace instance, multiple -e are allowed",
+		"	     --trigger <trigger>: enable a trace event trigger to the previous -e event",
 		"	  -q/--quiet print only a summary at the end",
 		"	  -P/--priority o:prio|r:prio|f:prio|d:runtime:period : set scheduling parameters",
 		"		o:prio - use SCHED_OTHER with prio",
@@ -312,13 +313,14 @@ struct osnoise_top_params *osnoise_top_parse_args(int argc, char **argv)
 			{"stop-total",		required_argument,	0, 'S'},
 			{"threshold",		required_argument,	0, 'T'},
 			{"trace",		optional_argument,	0, 't'},
+			{"trigger",		required_argument,	0, '0'},
 			{0, 0, 0, 0}
 		};
 
 		/* getopt_long stores the option index here. */
 		int option_index = 0;
 
-		c = getopt_long(argc, argv, "a:c:d:De:hp:P:qr:s:S:t::T:",
+		c = getopt_long(argc, argv, "a:c:d:De:hp:P:qr:s:S:t::T:0:",
 				 long_options, &option_index);
 
 		/* Detect the end of the options. */
@@ -402,6 +404,17 @@ struct osnoise_top_params *osnoise_top_parse_args(int argc, char **argv)
 		case 'T':
 			params->threshold = get_llong_from_str(optarg);
 			break;
+		case '0': /* trigger */
+			if (params->events) {
+				retval = trace_event_add_trigger(params->events, optarg);
+				if (retval) {
+					err_msg("Error adding trigger %s\n", optarg);
+					exit(EXIT_FAILURE);
+				}
+			} else {
+				osnoise_top_usage("--trigger requires a previous -e\n");
+			}
+			break;
 		default:
 			osnoise_top_usage("Invalid option");
 		}

tools/tracing/rtla/src/timerlat_hist.c

@@ -430,8 +430,8 @@ static void timerlat_hist_usage(char *usage)
 	char *msg[] = {
 		"",
 		"  usage: [rtla] timerlat hist [-h] [-q] [-d s] [-D] [-n] [-a us] [-p us] [-i us] [-T us] [-s us] \\",
-		"         [-t[=file]] [-e sys[:event]] [-c cpu-list] [-P priority] [-E N] [-b N] [--no-irq] \\",
-		"         [--no-thread] [--no-header] [--no-summary] [--no-index] [--with-zeros]",
+		"         [-t[=file]] [-e sys[:event]] [--trigger <trigger>] [-c cpu-list] [-P priority] [-E N] \\",
+		"         [-b N] [--no-irq] [--no-thread] [--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 latency is hit",
@@ -444,6 +444,7 @@ static void timerlat_hist_usage(char *usage)
 		"	  -D/--debug: print debug info",
 		"	  -t/--trace[=file]: save the stopped trace to [file|timerlat_trace.txt]",
 		"	  -e/--event <sys:event>: enable the <sys:event> in the trace instance, multiple -e are allowed",
+		"	     --trigger <trigger>: enable a trace event trigger to the previous -e event",
 		"	  -n/--nano: display data in nanoseconds",
 		"	  -b/--bucket-size N: set the histogram bucket size (default 1)",
 		"	  -E/--entries N: set the number of entries of the histogram (default 256)",
@@ -517,13 +518,14 @@ static struct timerlat_hist_params
 			{"no-summary",		no_argument,		0, '3'},
 			{"no-index",		no_argument,		0, '4'},
 			{"with-zeros",		no_argument,		0, '5'},
+			{"trigger",		required_argument,	0, '6'},
 			{0, 0, 0, 0}
 		};
 
 		/* getopt_long stores the option index here. */
 		int option_index = 0;
 
-		c = getopt_long(argc, argv, "a:c:b:d:e:E:Dhi:np:P:s:t::T:012345",
+		c = getopt_long(argc, argv, "a:c:b:d:e:E:Dhi:np:P:s:t::T:0123456:",
 				 long_options, &option_index);
 
 		/* detect the end of the options. */
@@ -632,6 +634,17 @@ static struct timerlat_hist_params
 		case '5': /* with zeros */
 			params->with_zeros = 1;
 			break;
+		case '6': /* trigger */
+			if (params->events) {
+				retval = trace_event_add_trigger(params->events, optarg);
+				if (retval) {
+					err_msg("Error adding trigger %s\n", optarg);
+					exit(EXIT_FAILURE);
+				}
+			} else {
+				timerlat_hist_usage("--trigger requires a previous -e\n");
+			}
+			break;
 		default:
 			timerlat_hist_usage("Invalid option");
 		}

tools/tracing/rtla/src/timerlat_top.c

@@ -268,7 +268,7 @@ static void timerlat_top_usage(char *usage)
 	static const char *const msg[] = {
 		"",
 		"  usage: rtla timerlat [top] [-h] [-q] [-a us] [-d s] [-D] [-n] [-p us] [-i us] [-T us] [-s us] \\",
-		"	  [[-t[=file]] [-e sys[:event]] [-c cpu-list] [-P priority]",
+		"	  [[-t[=file]] [-e sys[:event]] [--trigger <trigger>] [-c cpu-list] [-P priority]",
 		"",
 		"	  -h/--help: print this menu",
 		"	  -a/--auto: set automatic trace mode, stopping the session if argument in us latency is hit",
@@ -281,6 +281,7 @@ static void timerlat_top_usage(char *usage)
 		"	  -D/--debug: print debug info",
 		"	  -t/--trace[=file]: save the stopped trace to [file|timerlat_trace.txt]",
 		"	  -e/--event <sys:event>: enable the <sys:event> in the trace instance, multiple -e are allowed",
+		"	     --trigger <command>: enable a trace event trigger to the previous -e event",
 		"	  -n/--nano: display data in nanoseconds",
 		"	  -q/--quiet print only a summary at the end",
 		"	  -P/--priority o:prio|r:prio|f:prio|d:runtime:period : set scheduling parameters",
@@ -338,13 +339,14 @@ static struct timerlat_top_params
 			{"stack",		required_argument,	0, 's'},
 			{"thread",		required_argument,	0, 'T'},
 			{"trace",		optional_argument,	0, 't'},
+			{"trigger",		required_argument,	0, '0'},
 			{0, 0, 0, 0}
 		};
 
 		/* getopt_long stores the option index here. */
 		int option_index = 0;
 
-		c = getopt_long(argc, argv, "a:c:d:De:hi:np:P:qs:t::T:",
+		c = getopt_long(argc, argv, "a:c:d:De:hi:np:P:qs:t::T:0:",
 				 long_options, &option_index);
 
 		/* detect the end of the options. */
@@ -427,6 +429,17 @@ static struct timerlat_top_params
 			else
 				params->trace_output = "timerlat_trace.txt";
 			break;
+		case '0': /* trigger */
+			if (params->events) {
+				retval = trace_event_add_trigger(params->events, optarg);
+				if (retval) {
+					err_msg("Error adding trigger %s\n", optarg);
+					exit(EXIT_FAILURE);
+				}
+			} else {
+				timerlat_top_usage("--trigger requires a previous -e\n");
+			}
+			break;
 		default:
 			timerlat_top_usage("Invalid option");
 		}