rtla: Add -e/--event support

Add -e/--event option. This option enables 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.

This option is available for all current tools.

Link: https://lkml.kernel.org/r/6a3b753be9b1e811953995f7f21a86918ad13390.1646247211.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>

1 files changed, 26 insertions, 2 deletions

diff --git a/tools/tracing/rtla/src/timerlat_top.c b/tools/tracing/rtla/src/timerlat_top.c
index aef044832964..13bd922ab147 100644
--- a/tools/tracing/rtla/src/timerlat_top.c
+++ b/tools/tracing/rtla/src/timerlat_top.c
@@ -30,6 +30,7 @@ struct timerlat_top_params {
 	int			quiet;
 	int			set_sched;
 	struct sched_attr	sched_param;
+	struct trace_events	*events;
 };
 
 struct timerlat_top_cpu {
@@ -267,7 +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]] -c cpu-list] [-P priority]",
+		"	  [[-t[=file]] [-e sys[:event]] [-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",
@@ -279,6 +280,7 @@ static void timerlat_top_usage(char *usage)
 		"	  -d/--duration time[m|h|d]: duration of the session in seconds",
 		"	  -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",
 		"	  -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",
@@ -308,6 +310,7 @@ static struct timerlat_top_params
 *timerlat_top_parse_args(int argc, char **argv)
 {
 	struct timerlat_top_params *params;
+	struct trace_events *tevent;
 	long long auto_thresh;
 	int retval;
 	int c;
@@ -325,6 +328,7 @@ static struct timerlat_top_params
 			{"cpus",		required_argument,	0, 'c'},
 			{"debug",		no_argument,		0, 'D'},
 			{"duration",		required_argument,	0, 'd'},
+			{"event",		required_argument,	0, 'e'},
 			{"help",		no_argument,		0, 'h'},
 			{"irq",			required_argument,	0, 'i'},
 			{"nano",		no_argument,		0, 'n'},
@@ -340,7 +344,7 @@ static struct timerlat_top_params
 		/* getopt_long stores the option index here. */
 		int option_index = 0;
 
-		c = getopt_long(argc, argv, "a:c:d:Dhi:np:P:qs:t::T:",
+		c = getopt_long(argc, argv, "a:c:d:De:hi:np:P:qs:t::T:",
 				 long_options, &option_index);
 
 		/* detect the end of the options. */
@@ -375,6 +379,17 @@ static struct timerlat_top_params
 			if (!params->duration)
 				timerlat_top_usage("Invalid -D duration\n");
 			break;
+		case 'e':
+			tevent = trace_event_alloc(optarg);
+			if (!tevent) {
+				err_msg("Error alloc trace event");
+				exit(EXIT_FAILURE);
+			}
+
+			if (params->events)
+				tevent->next = params->events;
+			params->events = tevent;
+			break;
 		case 'h':
 		case '?':
 			timerlat_top_usage(NULL);
@@ -583,6 +598,13 @@ int timerlat_top_main(int argc, char *argv[])
 			err_msg("Failed to enable the trace instance\n");
 			goto out_top;
 		}
+
+		if (params->events) {
+			retval = trace_events_enable(&record->trace, params->events);
+			if (retval)
+				goto out_top;
+		}
+
 		trace_instance_start(&record->trace);
 	}
 
@@ -624,6 +646,8 @@ int timerlat_top_main(int argc, char *argv[])
 	}
 
 out_top:
+	trace_events_destroy(&record->trace, params->events);
+	params->events = NULL;
 	timerlat_free_top(top->data);
 	osnoise_destroy_tool(record);
 	osnoise_destroy_tool(top);