[PATCH v2 0/9] rtla/timerlat: Support actions on threshold and on end

[PATCH v2 0/9] rtla/timerlat: Support actions on threshold and on end

[Tomas Glozar]

This series adds a feature that allows to user to specify certain
kinds of "actions" to be executed at one of two places in the rtla
measurement: when tracing is stopped on latency threshold, and at the
end of tracing.

Two new options are added: --on-threshold, and --on-end, taking
the action as an argument. For example:

$ rtla timerlat hist -T 10 \
--on-threshold shell,command="echo Threshold"
--on-end shell,command="echo Tracing stopped"

will print "Threshold" if a thread latency higher than 10 microseconds
is reached, and "Tracing stopped" always at the end.

The list of possible actions is extensible and is covered in
the commit messages. Later, a documentation patch series will be sent
with clear explanation of every action and its syntax.

Notably, a special action "continue" resumes tracing. For example:

$ rtla timerlat hist -T 100 \
--on-threshold shell,command="echo Threshold" \
--on-threshold continue -d 10s

will print "Threshold" as many times as tracing is stopped after
thread latency reaches 100us.

The feature was inspired by a case where collecting perf data on rtla
latency overflow was required, which can be done by sending a signal
to the perf process.

Example of this with Intel PT aux buffer:

$ perf record --cpu 0 -e intel_pt// -S -- rtla timerlat top -q -T 100 \
-c 0 --on-threshold signal,pid=parent,num=12 --on-theshold continue

In general, the feature is aiming to allow integration with external
tooling. To implement even more flexibility, passing context to the
shell through environmental variables, or even an entire scripting
language with access to the rtla internals can be implemented if
needed.

Changes since v1:
- Dropped short options on suggestion from Arnaldo.
- Added documentation.

Tomas Glozar (9):
  rtla/timerlat: Introduce enum timerlat_tracing_mode
  rtla/timerlat: Add action on threshold feature
  rtla/timerlat_bpf: Allow resuming tracing
  rtla/timerlat: Add continue action
  rtla/timerlat: Add action on end feature
  rtla/tests: Check rtla output with grep
  rtla/tests: Add tests for actions
  rtla/tests: Limit duration to maximum of 10s
  Documentation/rtla: Add actions feature

 .../tools/rtla/common_timerlat_options.rst    |  64 +++++
 tools/tracing/rtla/src/Build                  |   1 +
 tools/tracing/rtla/src/actions.c              | 260 ++++++++++++++++++
 tools/tracing/rtla/src/actions.h              |  52 ++++
 tools/tracing/rtla/src/timerlat.bpf.c         |  13 +-
 tools/tracing/rtla/src/timerlat.c             |  24 +-
 tools/tracing/rtla/src/timerlat.h             |  24 +-
 tools/tracing/rtla/src/timerlat_bpf.c         |  13 +
 tools/tracing/rtla/src/timerlat_bpf.h         |   3 +
 tools/tracing/rtla/src/timerlat_hist.c        | 140 +++++++---
 tools/tracing/rtla/src/timerlat_top.c         | 165 +++++++----
 tools/tracing/rtla/tests/engine.sh            |  21 +-
 tools/tracing/rtla/tests/hwnoise.t            |   8 +-
 tools/tracing/rtla/tests/osnoise.t            |   4 +-
 tools/tracing/rtla/tests/timerlat.t           |  36 ++-
 15 files changed, 712 insertions(+), 116 deletions(-)
 create mode 100644 tools/tracing/rtla/src/actions.c
 create mode 100644 tools/tracing/rtla/src/actions.h

-- 
2.49.0

[PATCH v2 1/9] rtla/timerlat: Introduce enum timerlat_tracing_mode

[Tomas Glozar]

After the introduction of BPF-based sample collection, rtla-timerlat
effectively runs in one of three modes:

- Pure BPF mode, with tracefs only being used to set up the timerlat
tracer. Sample processing and stop on threshold are handled by BPF.

- tracefs mode. BPF is unsupported or kernel is lacking the necessary
trace event (osnoise:timerlat_sample). Stop on theshold is handled by
timerlat tracer stopping tracing in all instances.

- BPF/tracefs mixed mode - BPF is used for sample collection for top or
histogram, tracefs is used for trace output and/or auto-analysis. Stop
on threshold is handled both through BPF program, which stops sample
collection for top/histogram and wakes up rtla, and by timerlat
tracer, which stops tracing for trace output/auto-analysis instances.

Add enum timerlat_tracing_mode, with three values:

- TRACING_MODE_BPF
- TRACING_MODE_TRACEFS
- TRACING_MODE_MIXED

Those represent the modes described above. A field of this type is added
to struct timerlat_params, named "mode", replacing the no_bpf variable.
params->mode is set in timerlat_{top,hist}_parse_args to
TRACING_MODE_BPF or TRACING_MODE_MIXED based on whether trace output
and/or auto-analysis is requested. timerlat_{top,hist}_main then checks
if BPF is not unavailable or disabled, in that case, it sets
params->mode to TRACING_MODE_TRACEFS.

A condition is added to timerlat_apply_config that skips setting
timerlat tracer thresholds if params->mode is TRACING_MODE_BPF (those
are unnecessary, since they only turn off tracing, which is already
turned off in that case, since BPF is used to collect samples).

Signed-off-by: Tomas Glozar <tglozar@redhat.com>
---
 tools/tracing/rtla/src/timerlat.c      | 24 +++++++----
 tools/tracing/rtla/src/timerlat.h      | 18 ++++++++
 tools/tracing/rtla/src/timerlat_hist.c | 51 +++++++++++++----------
 tools/tracing/rtla/src/timerlat_top.c  | 57 +++++++++++++++-----------
 4 files changed, 97 insertions(+), 53 deletions(-)

diff --git a/tools/tracing/rtla/src/timerlat.c b/tools/tracing/rtla/src/timerlat.c
index c29e2ba2d7d8..63d6d43eafff 100644
--- a/tools/tracing/rtla/src/timerlat.c
+++ b/tools/tracing/rtla/src/timerlat.c
@@ -40,16 +40,22 @@ timerlat_apply_config(struct osnoise_tool *tool, struct timerlat_params *params)
 			CPU_SET(i, &params->monitored_cpus);
 	}
 
-	retval = osnoise_set_stop_us(tool->context, params->stop_us);
-	if (retval) {
-		err_msg("Failed to set stop us\n");
-		goto out_err;
-	}
+	if (params->mode != TRACING_MODE_BPF) {
+		/*
+		 * In tracefs and mixed mode, timerlat tracer handles stopping
+		 * on threshold
+		 */
+		retval = osnoise_set_stop_us(tool->context, params->stop_us);
+		if (retval) {
+			err_msg("Failed to set stop us\n");
+			goto out_err;
+		}
 
-	retval = osnoise_set_stop_total_us(tool->context, params->stop_total_us);
-	if (retval) {
-		err_msg("Failed to set stop total us\n");
-		goto out_err;
+		retval = osnoise_set_stop_total_us(tool->context, params->stop_total_us);
+		if (retval) {
+			err_msg("Failed to set stop total us\n");
+			goto out_err;
+		}
 	}
 
 
diff --git a/tools/tracing/rtla/src/timerlat.h b/tools/tracing/rtla/src/timerlat.h
index 73045aef23fa..e0a553545d03 100644
--- a/tools/tracing/rtla/src/timerlat.h
+++ b/tools/tracing/rtla/src/timerlat.h
@@ -1,6 +1,23 @@
 // SPDX-License-Identifier: GPL-2.0
 #include "osnoise.h"
 
+/*
+ * Define timerlat tracing mode.
+ *
+ * There are three tracing modes:
+ * - tracefs-only, used when BPF is unavailable.
+ * - BPF-only, used when BPF is available and neither trace saving nor
+ * auto-analysis are enabled.
+ * - mixed mode, used when BPF is available and either trace saving or
+ * auto-analysis is enabled (which rely on sample collection through
+ * tracefs).
+ */
+enum timerlat_tracing_mode {
+	TRACING_MODE_BPF,
+	TRACING_MODE_TRACEFS,
+	TRACING_MODE_MIXED,
+};
+
 struct timerlat_params {
 	/* Common params */
 	char			*cpus;
@@ -30,6 +47,7 @@ struct timerlat_params {
 	cpu_set_t		hk_cpu_set;
 	struct sched_attr	sched_param;
 	struct trace_events	*events;
+	enum timerlat_tracing_mode mode;
 	union {
 		struct {
 			/* top only */
diff --git a/tools/tracing/rtla/src/timerlat_hist.c b/tools/tracing/rtla/src/timerlat_hist.c
index 36d2294c963d..6cf260e8553b 100644
--- a/tools/tracing/rtla/src/timerlat_hist.c
+++ b/tools/tracing/rtla/src/timerlat_hist.c
@@ -802,6 +802,9 @@ static struct timerlat_params
 	params->bucket_size = 1;
 	params->entries = 256;
 
+	/* default to BPF mode */
+	params->mode = TRACING_MODE_BPF;
+
 	while (1) {
 		static struct option long_options[] = {
 			{"auto",		required_argument,	0, 'a'},
@@ -1054,6 +1057,13 @@ static struct timerlat_params
 	if (params->kernel_workload && params->user_workload)
 		timerlat_hist_usage("--kernel-threads and --user-threads are mutually exclusive!");
 
+	/*
+	 * If auto-analysis or trace output is enabled, switch from BPF mode to
+	 * mixed mode
+	 */
+	if (params->mode == TRACING_MODE_BPF && params->trace_output && !params->no_aa)
+		params->mode = TRACING_MODE_MIXED;
+
 	return params;
 }
 
@@ -1149,7 +1159,6 @@ int timerlat_hist_main(int argc, char *argv[])
 	pthread_t timerlat_u;
 	int retval;
 	int nr_cpus, i;
-	bool no_bpf = false;
 
 	params = timerlat_hist_parse_args(argc, argv);
 	if (!params)
@@ -1161,12 +1170,6 @@ int timerlat_hist_main(int argc, char *argv[])
 		goto out_exit;
 	}
 
-	retval = timerlat_hist_apply_config(tool, params);
-	if (retval) {
-		err_msg("Could not apply config\n");
-		goto out_free;
-	}
-
 	trace = &tool->trace;
 	/*
 	 * Save trace instance into global variable so that SIGINT can stop
@@ -1175,24 +1178,30 @@ int timerlat_hist_main(int argc, char *argv[])
 	 */
 	hist_inst = trace;
 
+	/*
+	 * Try to enable BPF, unless disabled explicitly.
+	 * If BPF enablement fails, fall back to tracefs mode.
+	 */
 	if (getenv("RTLA_NO_BPF") && strncmp(getenv("RTLA_NO_BPF"), "1", 2) == 0) {
 		debug_msg("RTLA_NO_BPF set, disabling BPF\n");
-		no_bpf = true;
-	}
-
-	if (!no_bpf && !tep_find_event_by_name(trace->tep, "osnoise", "timerlat_sample")) {
+		params->mode = TRACING_MODE_TRACEFS;
+	} else if (!tep_find_event_by_name(trace->tep, "osnoise", "timerlat_sample")) {
 		debug_msg("osnoise:timerlat_sample missing, disabling BPF\n");
-		no_bpf = true;
-	}
-
-	if (!no_bpf) {
+		params->mode = TRACING_MODE_TRACEFS;
+	} else {
 		retval = timerlat_bpf_init(params);
 		if (retval) {
 			debug_msg("Could not enable BPF\n");
-			no_bpf = true;
+			params->mode = TRACING_MODE_TRACEFS;
 		}
 	}
 
+	retval = timerlat_hist_apply_config(tool, params);
+	if (retval) {
+		err_msg("Could not apply config\n");
+		goto out_free;
+	}
+
 	retval = enable_timerlat(trace);
 	if (retval) {
 		err_msg("Failed to enable timerlat tracer\n");
@@ -1320,7 +1329,7 @@ int timerlat_hist_main(int argc, char *argv[])
 		trace_instance_start(&record->trace);
 	if (!params->no_aa)
 		trace_instance_start(&aa->trace);
-	if (no_bpf) {
+	if (params->mode == TRACING_MODE_TRACEFS) {
 		trace_instance_start(trace);
 	} else {
 		retval = timerlat_bpf_attach();
@@ -1333,7 +1342,7 @@ int timerlat_hist_main(int argc, char *argv[])
 	tool->start_time = time(NULL);
 	timerlat_hist_set_signals(params);
 
-	if (no_bpf) {
+	if (params->mode == TRACING_MODE_TRACEFS) {
 		while (!stop_tracing) {
 			sleep(params->sleep_time);
 
@@ -1362,7 +1371,7 @@ int timerlat_hist_main(int argc, char *argv[])
 	} else
 		timerlat_bpf_wait(-1);
 
-	if (!no_bpf) {
+	if (params->mode != TRACING_MODE_TRACEFS) {
 		timerlat_bpf_detach();
 		retval = timerlat_hist_bpf_pull_data(tool);
 		if (retval) {
@@ -1409,10 +1418,10 @@ int timerlat_hist_main(int argc, char *argv[])
 	osnoise_destroy_tool(aa);
 	osnoise_destroy_tool(record);
 	osnoise_destroy_tool(tool);
+	if (params->mode != TRACING_MODE_TRACEFS)
+		timerlat_bpf_destroy();
 	free(params);
 	free_cpu_idle_disable_states();
-	if (!no_bpf)
-		timerlat_bpf_destroy();
 out_exit:
 	exit(return_value);
 }
diff --git a/tools/tracing/rtla/src/timerlat_top.c b/tools/tracing/rtla/src/timerlat_top.c
index 7365e08fe986..1644eeb60181 100644
--- a/tools/tracing/rtla/src/timerlat_top.c
+++ b/tools/tracing/rtla/src/timerlat_top.c
@@ -559,6 +559,9 @@ static struct timerlat_params
 	/* display data in microseconds */
 	params->output_divisor = 1000;
 
+	/* default to BPF mode */
+	params->mode = TRACING_MODE_BPF;
+
 	while (1) {
 		static struct option long_options[] = {
 			{"auto",		required_argument,	0, 'a'},
@@ -790,6 +793,13 @@ static struct timerlat_params
 	if (params->kernel_workload && params->user_workload)
 		timerlat_top_usage("--kernel-threads and --user-threads are mutually exclusive!");
 
+	/*
+	 * If auto-analysis or trace output is enabled, switch from BPF mode to
+	 * mixed mode
+	 */
+	if (params->mode == TRACING_MODE_BPF && params->trace_output && !params->no_aa)
+		params->mode = TRACING_MODE_MIXED;
+
 	return params;
 }
 
@@ -994,7 +1004,6 @@ int timerlat_top_main(int argc, char *argv[])
 	char *max_lat;
 	int retval;
 	int nr_cpus, i;
-	bool no_bpf = false;
 
 	params = timerlat_top_parse_args(argc, argv);
 	if (!params)
@@ -1006,38 +1015,38 @@ int timerlat_top_main(int argc, char *argv[])
 		goto out_exit;
 	}
 
-	retval = timerlat_top_apply_config(top, params);
-	if (retval) {
-		err_msg("Could not apply config\n");
-		goto out_free;
-	}
-
 	trace = &top->trace;
 	/*
-	* Save trace instance into global variable so that SIGINT can stop
-	* the timerlat tracer.
-	* Otherwise, rtla could loop indefinitely when overloaded.
-	*/
+	 * Save trace instance into global variable so that SIGINT can stop
+	 * the timerlat tracer.
+	 * Otherwise, rtla could loop indefinitely when overloaded.
+	 */
 	top_inst = trace;
 
+	/*
+	 * Try to enable BPF, unless disabled explicitly.
+	 * If BPF enablement fails, fall back to tracefs mode.
+	 */
 	if (getenv("RTLA_NO_BPF") && strncmp(getenv("RTLA_NO_BPF"), "1", 2) == 0) {
 		debug_msg("RTLA_NO_BPF set, disabling BPF\n");
-		no_bpf = true;
-	}
-
-	if (!no_bpf && !tep_find_event_by_name(trace->tep, "osnoise", "timerlat_sample")) {
+		params->mode = TRACING_MODE_TRACEFS;
+	} else if (!tep_find_event_by_name(trace->tep, "osnoise", "timerlat_sample")) {
 		debug_msg("osnoise:timerlat_sample missing, disabling BPF\n");
-		no_bpf = true;
-	}
-
-	if (!no_bpf) {
+		params->mode = TRACING_MODE_TRACEFS;
+	} else {
 		retval = timerlat_bpf_init(params);
 		if (retval) {
 			debug_msg("Could not enable BPF\n");
-			no_bpf = true;
+			params->mode = TRACING_MODE_TRACEFS;
 		}
 	}
 
+	retval = timerlat_top_apply_config(top, params);
+	if (retval) {
+		err_msg("Could not apply config\n");
+		goto out_free;
+	}
+
 	retval = enable_timerlat(trace);
 	if (retval) {
 		err_msg("Failed to enable timerlat tracer\n");
@@ -1166,7 +1175,7 @@ int timerlat_top_main(int argc, char *argv[])
 		trace_instance_start(&record->trace);
 	if (!params->no_aa)
 		trace_instance_start(&aa->trace);
-	if (no_bpf) {
+	if (params->mode == TRACING_MODE_TRACEFS) {
 		trace_instance_start(trace);
 	} else {
 		retval = timerlat_bpf_attach();
@@ -1179,7 +1188,7 @@ int timerlat_top_main(int argc, char *argv[])
 	top->start_time = time(NULL);
 	timerlat_top_set_signals(params);
 
-	if (no_bpf)
+	if (params->mode == TRACING_MODE_TRACEFS)
 		retval = timerlat_top_main_loop(top, record, params, &params_u);
 	else
 		retval = timerlat_top_bpf_main_loop(top, record, params, &params_u);
@@ -1187,7 +1196,7 @@ int timerlat_top_main(int argc, char *argv[])
 	if (retval)
 		goto out_top;
 
-	if (!no_bpf)
+	if (params->mode != TRACING_MODE_TRACEFS)
 		timerlat_bpf_detach();
 
 	if (params->user_workload && !params_u.stopped_running) {
@@ -1239,6 +1248,8 @@ int timerlat_top_main(int argc, char *argv[])
 		osnoise_destroy_tool(aa);
 	osnoise_destroy_tool(record);
 	osnoise_destroy_tool(top);
+	if (params->mode != TRACING_MODE_TRACEFS)
+		timerlat_bpf_destroy();
 	free(params);
 	free_cpu_idle_disable_states();
 out_exit:
-- 
2.49.0

[PATCH v2 2/9] rtla/timerlat: Add action on threshold feature

[Tomas Glozar]

Extend the functionality provided by the -t/--trace option, which
triggers saving the contents of a tracefs buffer after tracing is
stopped, to support implementing arbitrary actions.

A new option, --on-threshold, is added, taking an argument
that further specifies the action. Actions added in this patch are:

- trace[,file=<filename>]: Saves tracefs buffer, optionally taking a
filename.
- signal,num=<sig>,pid=<pid>: Sends signal to process. "parent" might
be specified instead of number to send signal to parent process.
- shell,command=<command>: Execute shell command.

Multiple actions may be specified and will be executed in order,
including multiple actions of the same type. Trace output requested via
-t and -a now adds a trace action to the end of the list.

If an action fails, the following actions are not executed. For
example, this command:

$ rtla timerlat -T 20 --on-threshold trace \
--on-threshold shell,command="grep ipi_send timerlat_trace.txt" \
--on-threshold signal,num=2,pid=parent

will send signal 2 (SIGINT) to parent process, but only if saved trace
contains the text "ipi_send".

This way, the feature can be used for flexible reactions on latency
spikes, and allows combining rtla with other tooling like perf.

Signed-off-by: Tomas Glozar <tglozar@redhat.com>
---
 tools/tracing/rtla/src/Build           |   1 +
 tools/tracing/rtla/src/actions.c       | 235 +++++++++++++++++++++++++
 tools/tracing/rtla/src/actions.h       |  49 ++++++
 tools/tracing/rtla/src/timerlat.h      |   3 +-
 tools/tracing/rtla/src/timerlat_hist.c |  37 ++--
 tools/tracing/rtla/src/timerlat_top.c  |  38 ++--
 6 files changed, 341 insertions(+), 22 deletions(-)
 create mode 100644 tools/tracing/rtla/src/actions.c
 create mode 100644 tools/tracing/rtla/src/actions.h

diff --git a/tools/tracing/rtla/src/Build b/tools/tracing/rtla/src/Build
index 7bb7e39e391a..66631280b75b 100644
--- a/tools/tracing/rtla/src/Build
+++ b/tools/tracing/rtla/src/Build
@@ -1,5 +1,6 @@
 rtla-y += trace.o
 rtla-y += utils.o
+rtla-y += actions.o
 rtla-y += osnoise.o
 rtla-y += osnoise_top.o
 rtla-y += osnoise_hist.o
diff --git a/tools/tracing/rtla/src/actions.c b/tools/tracing/rtla/src/actions.c
new file mode 100644
index 000000000000..63bee5bdabfd
--- /dev/null
+++ b/tools/tracing/rtla/src/actions.c
@@ -0,0 +1,235 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <stdlib.h>
+#include <string.h>
+#include <signal.h>
+#include <unistd.h>
+
+#include "actions.h"
+#include "trace.h"
+#include "utils.h"
+
+/*
+ * actions_init - initialize struct actions
+ */
+void
+actions_init(struct actions *self)
+{
+	self->size = action_default_size;
+	self->list = calloc(self->size, sizeof(struct action));
+	self->len = 0;
+
+	memset(&self->present, 0, sizeof(self->present));
+
+	/* This has to be set by the user */
+	self->trace_output_inst = NULL;
+}
+
+/*
+ * actions_destroy - destroy struct actions
+ */
+void
+actions_destroy(struct actions *self)
+{
+	/* Free any action-specific data */
+	for (struct action *action = self->list; action < self->list + self->len; action++) {
+		if (action->type == ACTION_SHELL)
+			free(action->command);
+		if (action->type == ACTION_TRACE_OUTPUT)
+			free(action->trace_output);
+	}
+
+	/* Free action list */
+	free(self->list);
+}
+
+/*
+ * actions_new - Get pointer to new action
+ */
+static struct action *
+actions_new(struct actions *self)
+{
+	if (self->size >= self->len) {
+		self->size *= 2;
+		self->list = realloc(self->list, self->size * sizeof(struct action));
+	}
+
+	return &self->list[self->len++];
+}
+
+/*
+ * actions_add_trace_output - add an action to output trace
+ */
+int
+actions_add_trace_output(struct actions *self, const char *trace_output)
+{
+	struct action *action = actions_new(self);
+
+	self->present[ACTION_TRACE_OUTPUT] = true;
+	action->type = ACTION_TRACE_OUTPUT;
+	action->trace_output = calloc(strlen(trace_output) + 1, sizeof(char));
+	if (!action->trace_output)
+		return -1;
+	strcpy(action->trace_output, trace_output);
+
+	return 0;
+}
+
+/*
+ * actions_add_trace_output - add an action to send signal to a process
+ */
+int
+actions_add_signal(struct actions *self, int signal, int pid)
+{
+	struct action *action = actions_new(self);
+
+	self->present[ACTION_SIGNAL] = true;
+	action->type = ACTION_SIGNAL;
+	action->signal = signal;
+	action->pid = pid;
+
+	return 0;
+}
+
+/*
+ * actions_add_shell - add an action to execute a shell command
+ */
+int
+actions_add_shell(struct actions *self, const char *command)
+{
+	struct action *action = actions_new(self);
+
+	self->present[ACTION_SHELL] = true;
+	action->type = ACTION_SHELL;
+	action->command = calloc(strlen(command) + 1, sizeof(char));
+	if (!action->command)
+		return -1;
+	strcpy(action->command, command);
+
+	return 0;
+}
+
+/*
+ * actions_parse - add an action based on text specification
+ */
+int
+actions_parse(struct actions *self, const char *trigger)
+{
+	enum action_type type = ACTION_NONE;
+	char *token;
+	char trigger_c[strlen(trigger)];
+
+	/* For ACTION_SIGNAL */
+	int signal = 0, pid = 0;
+
+	/* For ACTION_TRACE_OUTPUT */
+	char *trace_output;
+
+	strcpy(trigger_c, trigger);
+	token = strtok(trigger_c, ",");
+
+	if (strcmp(token, "trace") == 0)
+		type = ACTION_TRACE_OUTPUT;
+	else if (strcmp(token, "signal") == 0)
+		type = ACTION_SIGNAL;
+	else if (strcmp(token, "shell") == 0)
+		type = ACTION_SHELL;
+	else
+		/* Invalid trigger type */
+		return -1;
+
+	token = strtok(NULL, ",");
+
+	switch (type) {
+	case ACTION_TRACE_OUTPUT:
+		/* Takes no argument */
+		if (token == NULL)
+			trace_output = "timerlat_trace.txt";
+		else {
+			if (strlen(token) > 5 && strncmp(token, "file=", 5) == 0) {
+				trace_output = token + 5;
+			} else {
+				/* Invalid argument */
+				return -1;
+			}
+
+			token = strtok(NULL, ",");
+			if (token != NULL)
+				/* Only one argument allowed */
+				return -1;
+		}
+		return actions_add_trace_output(self, trace_output);
+	case ACTION_SIGNAL:
+		/* Takes two arguments, num (signal) and pid */
+		while (token != NULL) {
+			if (strlen(token) > 4 && strncmp(token, "num=", 4) == 0) {
+				signal = atoi(token + 4);
+			} else if (strlen(token) > 4 && strncmp(token, "pid=", 4) == 0) {
+				if (strncmp(token + 4, "parent", 7) == 0)
+					pid = -1;
+				else
+					pid = atoi(token + 4);
+			} else {
+				/* Invalid argument */
+				return -1;
+			}
+
+			token = strtok(NULL, ",");
+		}
+
+		if (!signal || !pid)
+			/* Missing argument */
+			return -1;
+
+		return actions_add_signal(self, signal, pid);
+	case ACTION_SHELL:
+		if (token == NULL)
+			return -1;
+		if (strlen(token) > 8 && strncmp(token, "command=", 8) == 0)
+			return actions_add_shell(self, token + 8);
+		return -1;
+	default:
+		return -1;
+	}
+}
+
+/*
+ * actions_perform - perform all actions
+ */
+int
+actions_perform(const struct actions *self)
+{
+	int pid, retval;
+	const struct action *action;
+
+	for (action = self->list; action < self->list + self->len; action++) {
+		switch (action->type) {
+		case ACTION_TRACE_OUTPUT:
+			retval = save_trace_to_file(self->trace_output_inst, action->trace_output);
+			if (retval) {
+				err_msg("Error saving trace\n");
+				return retval;
+			}
+			break;
+		case ACTION_SIGNAL:
+			if (action->pid == -1)
+				pid = getppid();
+			else
+				pid = action->pid;
+			retval = kill(pid, action->signal);
+			if (retval) {
+				err_msg("Error sending signal\n");
+				return retval;
+			}
+			break;
+		case ACTION_SHELL:
+			retval = system(action->command);
+			if (retval)
+				return retval;
+			break;
+		default:
+			break;
+		}
+	}
+
+	return 0;
+}
diff --git a/tools/tracing/rtla/src/actions.h b/tools/tracing/rtla/src/actions.h
new file mode 100644
index 000000000000..076bbff8519e
--- /dev/null
+++ b/tools/tracing/rtla/src/actions.h
@@ -0,0 +1,49 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#include <tracefs.h>
+#include <stdbool.h>
+
+enum action_type {
+	ACTION_NONE = 0,
+	ACTION_TRACE_OUTPUT,
+	ACTION_SIGNAL,
+	ACTION_SHELL,
+	ACTION_FIELD_N
+};
+
+struct action {
+	enum action_type type;
+	union {
+		struct {
+			/* For ACTION_TRACE_OUTPUT */
+			char *trace_output;
+		};
+		struct {
+			/* For ACTION_SIGNAL */
+			int signal;
+			int pid;
+		};
+		struct {
+			/* For ACTION_SHELL */
+			char *command;
+		};
+	};
+};
+
+static const int action_default_size = 8;
+
+struct actions {
+	struct action *list;
+	int len, size;
+	bool present[ACTION_FIELD_N];
+
+	/* External dependencies */
+	struct tracefs_instance *trace_output_inst;
+};
+
+void actions_init(struct actions *self);
+void actions_destroy(struct actions *self);
+int actions_add_trace_output(struct actions *self, const char *trace_output);
+int actions_add_signal(struct actions *self, int signal, int pid);
+int actions_add_shell(struct actions *self, const char *command);
+int actions_parse(struct actions *self, const char *trigger);
+int actions_perform(const struct actions *self);
diff --git a/tools/tracing/rtla/src/timerlat.h b/tools/tracing/rtla/src/timerlat.h
index e0a553545d03..d1fcf9a97621 100644
--- a/tools/tracing/rtla/src/timerlat.h
+++ b/tools/tracing/rtla/src/timerlat.h
@@ -1,4 +1,5 @@
 // SPDX-License-Identifier: GPL-2.0
+#include "actions.h"
 #include "osnoise.h"
 
 /*
@@ -22,7 +23,6 @@ struct timerlat_params {
 	/* Common params */
 	char			*cpus;
 	cpu_set_t		monitored_cpus;
-	char			*trace_output;
 	char			*cgroup_name;
 	unsigned long long	runtime;
 	long long		stop_us;
@@ -48,6 +48,7 @@ struct timerlat_params {
 	struct sched_attr	sched_param;
 	struct trace_events	*events;
 	enum timerlat_tracing_mode mode;
+	struct actions actions;
 	union {
 		struct {
 			/* top only */
diff --git a/tools/tracing/rtla/src/timerlat_hist.c b/tools/tracing/rtla/src/timerlat_hist.c
index 6cf260e8553b..d975d2cd6604 100644
--- a/tools/tracing/rtla/src/timerlat_hist.c
+++ b/tools/tracing/rtla/src/timerlat_hist.c
@@ -757,6 +757,7 @@ static void timerlat_hist_usage(char *usage)
 		"	     --warm-up s: let the workload run for s seconds before collecting data",
 		"	     --trace-buffer-size kB: set the per-cpu trace buffer size in kB",
 		"	     --deepest-idle-state n: only go down to idle state n on cpus used by timerlat to reduce exit from idle latency",
+		"	     --on-threshold <action>: define action to be executed at latency threshold, multiple are allowed",
 		NULL,
 	};
 
@@ -786,11 +787,14 @@ static struct timerlat_params
 	int auto_thresh;
 	int retval;
 	int c;
+	char *trace_output = NULL;
 
 	params = calloc(1, sizeof(*params));
 	if (!params)
 		exit(1);
 
+	actions_init(&params->actions);
+
 	/* disabled by default */
 	params->dma_latency = -1;
 
@@ -841,6 +845,7 @@ static struct timerlat_params
 			{"warm-up",		required_argument,	0, '\2'},
 			{"trace-buffer-size",	required_argument,	0, '\3'},
 			{"deepest-idle-state",	required_argument,	0, '\4'},
+			{"on-threshold",	required_argument,	0, '\5'},
 			{0, 0, 0, 0}
 		};
 
@@ -866,7 +871,7 @@ static struct timerlat_params
 			params->print_stack = auto_thresh;
 
 			/* set trace */
-			params->trace_output = "timerlat_trace.txt";
+			trace_output = "timerlat_trace.txt";
 
 			break;
 		case 'c':
@@ -956,13 +961,13 @@ static struct timerlat_params
 		case 't':
 			if (optarg) {
 				if (optarg[0] == '=')
-					params->trace_output = &optarg[1];
+					trace_output = &optarg[1];
 				else
-					params->trace_output = &optarg[0];
+					trace_output = &optarg[0];
 			} else if (optind < argc && argv[optind][0] != '-')
-				params->trace_output = argv[optind];
+				trace_output = argv[optind];
 			else
-				params->trace_output = "timerlat_trace.txt";
+				trace_output = "timerlat_trace.txt";
 			break;
 		case 'u':
 			params->user_workload = 1;
@@ -1032,11 +1037,21 @@ static struct timerlat_params
 		case '\4':
 			params->deepest_idle_state = get_llong_from_str(optarg);
 			break;
+		case '\5':
+			retval = actions_parse(&params->actions, optarg);
+			if (retval) {
+				err_msg("Invalid action %s\n", optarg);
+				exit(EXIT_FAILURE);
+			}
+			break;
 		default:
 			timerlat_hist_usage("Invalid option");
 		}
 	}
 
+	if (trace_output)
+		actions_add_trace_output(&params->actions, trace_output);
+
 	if (geteuid()) {
 		err_msg("rtla needs root permission\n");
 		exit(EXIT_FAILURE);
@@ -1061,7 +1076,8 @@ static struct timerlat_params
 	 * If auto-analysis or trace output is enabled, switch from BPF mode to
 	 * mixed mode
 	 */
-	if (params->mode == TRACING_MODE_BPF && params->trace_output && !params->no_aa)
+	if (params->mode == TRACING_MODE_BPF &&
+	    (params->actions.present[ACTION_TRACE_OUTPUT] || !params->no_aa))
 		params->mode = TRACING_MODE_MIXED;
 
 	return params;
@@ -1254,12 +1270,13 @@ int timerlat_hist_main(int argc, char *argv[])
 		}
 	}
 
-	if (params->trace_output) {
+	if (params->actions.present[ACTION_TRACE_OUTPUT]) {
 		record = osnoise_init_trace_tool("timerlat");
 		if (!record) {
 			err_msg("Failed to enable the trace instance\n");
 			goto out_free;
 		}
+		params->actions.trace_output_inst = record->trace.inst;
 
 		if (params->events) {
 			retval = trace_events_enable(&record->trace, params->events);
@@ -1325,7 +1342,7 @@ int timerlat_hist_main(int argc, char *argv[])
 	 * tracing while enabling other instances. The trace instance is the
 	 * one with most valuable information.
 	 */
-	if (params->trace_output)
+	if (params->actions.present[ACTION_TRACE_OUTPUT])
 		trace_instance_start(&record->trace);
 	if (!params->no_aa)
 		trace_instance_start(&aa->trace);
@@ -1395,8 +1412,7 @@ int timerlat_hist_main(int argc, char *argv[])
 		if (!params->no_aa)
 			timerlat_auto_analysis(params->stop_us, params->stop_total_us);
 
-		save_trace_to_file(record ? record->trace.inst : NULL,
-				   params->trace_output);
+		actions_perform(&params->actions);
 		return_value = FAILED;
 	}
 
@@ -1418,6 +1434,7 @@ int timerlat_hist_main(int argc, char *argv[])
 	osnoise_destroy_tool(aa);
 	osnoise_destroy_tool(record);
 	osnoise_destroy_tool(tool);
+	actions_destroy(&params->actions);
 	if (params->mode != TRACING_MODE_TRACEFS)
 		timerlat_bpf_destroy();
 	free(params);
diff --git a/tools/tracing/rtla/src/timerlat_top.c b/tools/tracing/rtla/src/timerlat_top.c
index 1644eeb60181..cdbfda009974 100644
--- a/tools/tracing/rtla/src/timerlat_top.c
+++ b/tools/tracing/rtla/src/timerlat_top.c
@@ -516,6 +516,7 @@ static void timerlat_top_usage(char *usage)
 		"	     --warm-up s: let the workload run for s seconds before collecting data",
 		"	     --trace-buffer-size kB: set the per-cpu trace buffer size in kB",
 		"	     --deepest-idle-state n: only go down to idle state n on cpus used by timerlat to reduce exit from idle latency",
+		"	     --on-threshold <action>: define action to be executed at latency threshold, multiple are allowed",
 		NULL,
 	};
 
@@ -545,11 +546,14 @@ static struct timerlat_params
 	long long auto_thresh;
 	int retval;
 	int c;
+	char *trace_output = NULL;
 
 	params = calloc(1, sizeof(*params));
 	if (!params)
 		exit(1);
 
+	actions_init(&params->actions);
+
 	/* disabled by default */
 	params->dma_latency = -1;
 
@@ -592,6 +596,7 @@ static struct timerlat_params
 			{"warm-up",		required_argument,	0, '6'},
 			{"trace-buffer-size",	required_argument,	0, '7'},
 			{"deepest-idle-state",	required_argument,	0, '8'},
+			{"on-threshold",	required_argument,	0, '9'},
 			{0, 0, 0, 0}
 		};
 
@@ -617,7 +622,7 @@ static struct timerlat_params
 			params->print_stack = auto_thresh;
 
 			/* set trace */
-			params->trace_output = "timerlat_trace.txt";
+			trace_output = "timerlat_trace.txt";
 			break;
 		case '5':
 			/* it is here because it is similar to -a */
@@ -712,14 +717,13 @@ static struct timerlat_params
 		case 't':
 			if (optarg) {
 				if (optarg[0] == '=')
-					params->trace_output = &optarg[1];
+					trace_output = &optarg[1];
 				else
-					params->trace_output = &optarg[0];
+					trace_output = &optarg[0];
 			} else if (optind < argc && argv[optind][0] != '-')
-				params->trace_output = argv[optind];
+				trace_output = argv[optind];
 			else
-				params->trace_output = "timerlat_trace.txt";
-
+				trace_output = "timerlat_trace.txt";
 			break;
 		case 'u':
 			params->user_workload = true;
@@ -771,11 +775,21 @@ static struct timerlat_params
 		case '8':
 			params->deepest_idle_state = get_llong_from_str(optarg);
 			break;
+		case '9':
+			retval = actions_parse(&params->actions, optarg);
+			if (retval) {
+				err_msg("Invalid action %s\n", optarg);
+				exit(EXIT_FAILURE);
+			}
+			break;
 		default:
 			timerlat_top_usage("Invalid option");
 		}
 	}
 
+	if (trace_output)
+		actions_add_trace_output(&params->actions, trace_output);
+
 	if (geteuid()) {
 		err_msg("rtla needs root permission\n");
 		exit(EXIT_FAILURE);
@@ -797,7 +811,8 @@ static struct timerlat_params
 	 * If auto-analysis or trace output is enabled, switch from BPF mode to
 	 * mixed mode
 	 */
-	if (params->mode == TRACING_MODE_BPF && params->trace_output && !params->no_aa)
+	if (params->mode == TRACING_MODE_BPF &&
+	    (params->actions.present[ACTION_TRACE_OUTPUT] || !params->no_aa))
 		params->mode = TRACING_MODE_MIXED;
 
 	return params;
@@ -1099,12 +1114,13 @@ int timerlat_top_main(int argc, char *argv[])
 		}
 	}
 
-	if (params->trace_output) {
+	if (params->actions.present[ACTION_TRACE_OUTPUT]) {
 		record = osnoise_init_trace_tool("timerlat");
 		if (!record) {
 			err_msg("Failed to enable the trace instance\n");
 			goto out_free;
 		}
+		params->actions.trace_output_inst = record->trace.inst;
 
 		if (params->events) {
 			retval = trace_events_enable(&record->trace, params->events);
@@ -1171,7 +1187,7 @@ int timerlat_top_main(int argc, char *argv[])
 	 * tracing while enabling other instances. The trace instance is the
 	 * one with most valuable information.
 	 */
-	if (params->trace_output)
+	if (params->actions.present[ACTION_TRACE_OUTPUT])
 		trace_instance_start(&record->trace);
 	if (!params->no_aa)
 		trace_instance_start(&aa->trace);
@@ -1214,8 +1230,7 @@ int timerlat_top_main(int argc, char *argv[])
 		if (!params->no_aa)
 			timerlat_auto_analysis(params->stop_us, params->stop_total_us);
 
-		save_trace_to_file(record ? record->trace.inst : NULL,
-				   params->trace_output);
+		actions_perform(&params->actions);
 		return_value = FAILED;
 	} else if (params->aa_only) {
 		/*
@@ -1248,6 +1263,7 @@ int timerlat_top_main(int argc, char *argv[])
 		osnoise_destroy_tool(aa);
 	osnoise_destroy_tool(record);
 	osnoise_destroy_tool(top);
+	actions_destroy(&params->actions);
 	if (params->mode != TRACING_MODE_TRACEFS)
 		timerlat_bpf_destroy();
 	free(params);
-- 
2.49.0

[PATCH v2 3/9] rtla/timerlat_bpf: Allow resuming tracing

[Tomas Glozar]

Currently, rtla-timerlat BPF program uses a global variable stored in a
.bss section to store whether tracing has been stopped.

Move the information to a separate map, so that it is easily writable
from userspace, and add a function that clears the value, resuming
tracing after it has been stopped.

Signed-off-by: Tomas Glozar <tglozar@redhat.com>
---
 tools/tracing/rtla/src/timerlat.bpf.c | 13 +++++++++----
 tools/tracing/rtla/src/timerlat_bpf.c | 13 +++++++++++++
 tools/tracing/rtla/src/timerlat_bpf.h |  3 +++
 3 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/tools/tracing/rtla/src/timerlat.bpf.c b/tools/tracing/rtla/src/timerlat.bpf.c
index 96196d46e170..084cd10c21fc 100644
--- a/tools/tracing/rtla/src/timerlat.bpf.c
+++ b/tools/tracing/rtla/src/timerlat.bpf.c
@@ -28,6 +28,13 @@ struct {
 	__type(value, unsigned long long);
 } summary_irq SEC(".maps"), summary_thread SEC(".maps"), summary_user SEC(".maps");
 
+struct {
+	__uint(type, BPF_MAP_TYPE_ARRAY);
+	__uint(max_entries, 1);
+	__type(key, unsigned int);
+	__type(value, unsigned long long);
+} stop_tracing SEC(".maps");
+
 struct {
 	__uint(type, BPF_MAP_TYPE_RINGBUF);
 	__uint(max_entries, 1);
@@ -41,8 +48,6 @@ const volatile int irq_threshold;
 const volatile int thread_threshold;
 const volatile bool aa_only;
 
-int stop_tracing;
-
 nosubprog unsigned long long map_get(void *map,
 				     unsigned int key)
 {
@@ -109,7 +114,7 @@ nosubprog void set_stop_tracing(void)
 	int value = 0;
 
 	/* Suppress further sample processing */
-	stop_tracing = 1;
+	map_set(&stop_tracing, 0, 1);
 
 	/* Signal to userspace */
 	bpf_ringbuf_output(&signal_stop_tracing, &value, sizeof(value), 0);
@@ -121,7 +126,7 @@ int handle_timerlat_sample(struct trace_event_raw_timerlat_sample *tp_args)
 	unsigned long long latency, latency_us;
 	int bucket;
 
-	if (stop_tracing)
+	if (map_get(&stop_tracing, 0))
 		return 0;
 
 	latency = tp_args->timer_latency / output_divisor;
diff --git a/tools/tracing/rtla/src/timerlat_bpf.c b/tools/tracing/rtla/src/timerlat_bpf.c
index 0bc44ce5d69b..1666215dd687 100644
--- a/tools/tracing/rtla/src/timerlat_bpf.c
+++ b/tools/tracing/rtla/src/timerlat_bpf.c
@@ -106,6 +106,19 @@ int timerlat_bpf_wait(int timeout)
 	return retval;
 }
 
+/*
+ * timerlat_bpf_restart_tracing - restart stopped tracing
+ */
+int timerlat_bpf_restart_tracing(void)
+{
+	unsigned int key = 0;
+	unsigned long long value = 0;
+
+	return bpf_map__update_elem(bpf->maps.stop_tracing,
+				    &key, sizeof(key),
+				    &value, sizeof(value), BPF_ANY);
+}
+
 static int get_value(struct bpf_map *map_irq,
 		     struct bpf_map *map_thread,
 		     struct bpf_map *map_user,
diff --git a/tools/tracing/rtla/src/timerlat_bpf.h b/tools/tracing/rtla/src/timerlat_bpf.h
index f1b54dbddb0e..118487436d30 100644
--- a/tools/tracing/rtla/src/timerlat_bpf.h
+++ b/tools/tracing/rtla/src/timerlat_bpf.h
@@ -18,6 +18,7 @@ int timerlat_bpf_attach(void);
 void timerlat_bpf_detach(void);
 void timerlat_bpf_destroy(void);
 int timerlat_bpf_wait(int timeout);
+int timerlat_bpf_restart_tracing(void);
 int timerlat_bpf_get_hist_value(int key,
 				long long *value_irq,
 				long long *value_thread,
@@ -28,6 +29,7 @@ int timerlat_bpf_get_summary_value(enum summary_field key,
 				   long long *value_thread,
 				   long long *value_user,
 				   int cpus);
+
 static inline int have_libbpf_support(void) { return 1; }
 #else
 static inline int timerlat_bpf_init(struct timerlat_params *params)
@@ -38,6 +40,7 @@ static inline int timerlat_bpf_attach(void) { return -1; }
 static inline void timerlat_bpf_detach(void) { };
 static inline void timerlat_bpf_destroy(void) { };
 static inline int timerlat_bpf_wait(int timeout) { return -1; }
+static inline int timerlat_bpf_restart_tracing(void) { return -1; };
 static inline int timerlat_bpf_get_hist_value(int key,
 					      long long *value_irq,
 					      long long *value_thread,
-- 
2.49.0

[PATCH v2 4/9] rtla/timerlat: Add continue action

[Tomas Glozar]

Introduce option to resume tracing after a latency threshold overflow.
The option is implemented as an action named "continue".

Example:
$ rtla timerlat top -q -T 200 -d 1s --on-threshold \
exec,command="echo Threshold" --on-threshold continue
Threshold
Threshold
Threshold
                                     Timer Latency
...

The feature is supported for both hist and top. After the continue
action is executed, processing of the list of actions is stopped and
tracing is resumed.

Signed-off-by: Tomas Glozar <tglozar@redhat.com>
---
 tools/tracing/rtla/src/actions.c       | 27 +++++++++++-
 tools/tracing/rtla/src/actions.h       |  5 ++-
 tools/tracing/rtla/src/timerlat_hist.c | 40 +++++++++++++++---
 tools/tracing/rtla/src/timerlat_top.c  | 57 ++++++++++++++++----------
 4 files changed, 100 insertions(+), 29 deletions(-)

diff --git a/tools/tracing/rtla/src/actions.c b/tools/tracing/rtla/src/actions.c
index 63bee5bdabfd..aaf0808125d7 100644
--- a/tools/tracing/rtla/src/actions.c
+++ b/tools/tracing/rtla/src/actions.c
@@ -17,6 +17,7 @@ actions_init(struct actions *self)
 	self->size = action_default_size;
 	self->list = calloc(self->size, sizeof(struct action));
 	self->len = 0;
+	self->continue_flag = false;
 
 	memset(&self->present, 0, sizeof(self->present));
 
@@ -108,6 +109,20 @@ actions_add_shell(struct actions *self, const char *command)
 	return 0;
 }
 
+/*
+ * actions_add_continue - add an action to resume measurement
+ */
+int
+actions_add_continue(struct actions *self)
+{
+	struct action *action = actions_new(self);
+
+	self->present[ACTION_CONTINUE] = true;
+	action->type = ACTION_CONTINUE;
+
+	return 0;
+}
+
 /*
  * actions_parse - add an action based on text specification
  */
@@ -133,6 +148,8 @@ actions_parse(struct actions *self, const char *trigger)
 		type = ACTION_SIGNAL;
 	else if (strcmp(token, "shell") == 0)
 		type = ACTION_SHELL;
+	else if (strcmp(token, "continue") == 0)
+		type = ACTION_CONTINUE;
 	else
 		/* Invalid trigger type */
 		return -1;
@@ -187,6 +204,11 @@ actions_parse(struct actions *self, const char *trigger)
 		if (strlen(token) > 8 && strncmp(token, "command=", 8) == 0)
 			return actions_add_shell(self, token + 8);
 		return -1;
+	case ACTION_CONTINUE:
+		/* Takes no argument */
+		if (token != NULL)
+			return -1;
+		return actions_add_continue(self);
 	default:
 		return -1;
 	}
@@ -196,7 +218,7 @@ actions_parse(struct actions *self, const char *trigger)
  * actions_perform - perform all actions
  */
 int
-actions_perform(const struct actions *self)
+actions_perform(struct actions *self)
 {
 	int pid, retval;
 	const struct action *action;
@@ -226,6 +248,9 @@ actions_perform(const struct actions *self)
 			if (retval)
 				return retval;
 			break;
+		case ACTION_CONTINUE:
+			self->continue_flag = true;
+			return 0;
 		default:
 			break;
 		}
diff --git a/tools/tracing/rtla/src/actions.h b/tools/tracing/rtla/src/actions.h
index 076bbff8519e..b10a19d55c49 100644
--- a/tools/tracing/rtla/src/actions.h
+++ b/tools/tracing/rtla/src/actions.h
@@ -7,6 +7,7 @@ enum action_type {
 	ACTION_TRACE_OUTPUT,
 	ACTION_SIGNAL,
 	ACTION_SHELL,
+	ACTION_CONTINUE,
 	ACTION_FIELD_N
 };
 
@@ -35,6 +36,7 @@ struct actions {
 	struct action *list;
 	int len, size;
 	bool present[ACTION_FIELD_N];
+	bool continue_flag;
 
 	/* External dependencies */
 	struct tracefs_instance *trace_output_inst;
@@ -45,5 +47,6 @@ void actions_destroy(struct actions *self);
 int actions_add_trace_output(struct actions *self, const char *trace_output);
 int actions_add_signal(struct actions *self, int signal, int pid);
 int actions_add_shell(struct actions *self, const char *command);
+int actions_add_continue(struct actions *self);
 int actions_parse(struct actions *self, const char *trigger);
-int actions_perform(const struct actions *self);
+int actions_perform(struct actions *self);
diff --git a/tools/tracing/rtla/src/timerlat_hist.c b/tools/tracing/rtla/src/timerlat_hist.c
index d975d2cd6604..4f13a8f92711 100644
--- a/tools/tracing/rtla/src/timerlat_hist.c
+++ b/tools/tracing/rtla/src/timerlat_hist.c
@@ -1374,8 +1374,20 @@ int timerlat_hist_main(int argc, char *argv[])
 				goto out_hist;
 			}
 
-			if (osnoise_trace_is_off(tool, record))
-				break;
+			if (osnoise_trace_is_off(tool, record)) {
+				actions_perform(&params->actions);
+
+				if (!params->actions.continue_flag)
+					/* continue flag not set, break */
+					break;
+
+				/* continue action reached, re-enable tracing */
+				if (params->actions.present[ACTION_TRACE_OUTPUT])
+					trace_instance_start(&record->trace);
+				if (!params->no_aa)
+					trace_instance_start(&aa->trace);
+				trace_instance_start(trace);
+			}
 
 			/* is there still any user-threads ? */
 			if (params->user_workload) {
@@ -1385,8 +1397,27 @@ int timerlat_hist_main(int argc, char *argv[])
 				}
 			}
 		}
-	} else
-		timerlat_bpf_wait(-1);
+	} else {
+		while (!stop_tracing) {
+			timerlat_bpf_wait(-1);
+
+			if (!stop_tracing) {
+				/* Threshold overflow, perform actions on threshold */
+				actions_perform(&params->actions);
+
+				if (!params->actions.continue_flag)
+					/* continue flag not set, break */
+					break;
+
+				/* continue action reached, re-enable tracing */
+				if (params->actions.present[ACTION_TRACE_OUTPUT])
+					trace_instance_start(&record->trace);
+				if (!params->no_aa)
+					trace_instance_start(&aa->trace);
+				timerlat_bpf_restart_tracing();
+			}
+		}
+	}
 
 	if (params->mode != TRACING_MODE_TRACEFS) {
 		timerlat_bpf_detach();
@@ -1412,7 +1443,6 @@ int timerlat_hist_main(int argc, char *argv[])
 		if (!params->no_aa)
 			timerlat_auto_analysis(params->stop_us, params->stop_total_us);
 
-		actions_perform(&params->actions);
 		return_value = FAILED;
 	}
 
diff --git a/tools/tracing/rtla/src/timerlat_top.c b/tools/tracing/rtla/src/timerlat_top.c
index cdbfda009974..60f9c78cb272 100644
--- a/tools/tracing/rtla/src/timerlat_top.c
+++ b/tools/tracing/rtla/src/timerlat_top.c
@@ -906,6 +906,7 @@ timerlat_top_set_signals(struct timerlat_params *params)
 static int
 timerlat_top_main_loop(struct osnoise_tool *top,
 		       struct osnoise_tool *record,
+		       struct osnoise_tool *aa,
 		       struct timerlat_params *params,
 		       struct timerlat_u_params *params_u)
 {
@@ -932,8 +933,20 @@ timerlat_top_main_loop(struct osnoise_tool *top,
 		if (!params->quiet)
 			timerlat_print_stats(params, top);
 
-		if (osnoise_trace_is_off(top, record))
-			break;
+		if (osnoise_trace_is_off(top, record)) {
+			actions_perform(&params->actions);
+
+			if (!params->actions.continue_flag)
+				/* continue flag not set, break */
+				break;
+
+			/* continue action reached, re-enable tracing */
+			if (params->actions.present[ACTION_TRACE_OUTPUT])
+				trace_instance_start(&record->trace);
+			if (!params->no_aa)
+				trace_instance_start(&aa->trace);
+			trace_instance_start(trace);
+		}
 
 		/* is there still any user-threads ? */
 		if (params->user_workload) {
@@ -953,6 +966,7 @@ timerlat_top_main_loop(struct osnoise_tool *top,
 static int
 timerlat_top_bpf_main_loop(struct osnoise_tool *top,
 			   struct osnoise_tool *record,
+			   struct osnoise_tool *aa,
 			   struct timerlat_params *params,
 			   struct timerlat_u_params *params_u)
 {
@@ -964,22 +978,9 @@ timerlat_top_bpf_main_loop(struct osnoise_tool *top,
 		return 0;
 	}
 
-	if (params->quiet) {
-		/* Quiet mode: wait for stop and then, print results */
-		timerlat_bpf_wait(-1);
-
-		retval = timerlat_top_bpf_pull_data(top);
-		if (retval) {
-			err_msg("Error pulling BPF data\n");
-			return retval;
-		}
-
-		return 0;
-	}
-
 	/* Pull and display data in a loop */
 	while (!stop_tracing) {
-		wait_retval = timerlat_bpf_wait(params->sleep_time);
+		wait_retval = timerlat_bpf_wait(params->quiet ? -1 : params->sleep_time);
 
 		retval = timerlat_top_bpf_pull_data(top);
 		if (retval) {
@@ -987,11 +988,24 @@ timerlat_top_bpf_main_loop(struct osnoise_tool *top,
 			return retval;
 		}
 
-		timerlat_print_stats(params, top);
+		if (!params->quiet)
+			timerlat_print_stats(params, top);
 
-		if (wait_retval == 1)
+		if (wait_retval == 1) {
 			/* Stopping requested by tracer */
-			break;
+			actions_perform(&params->actions);
+
+			if (!params->actions.continue_flag)
+				/* continue flag not set, break */
+				break;
+
+			/* continue action reached, re-enable tracing */
+			if (params->actions.present[ACTION_TRACE_OUTPUT])
+				trace_instance_start(&record->trace);
+			if (!params->no_aa)
+				trace_instance_start(&aa->trace);
+			timerlat_bpf_restart_tracing();
+		}
 
 		/* is there still any user-threads ? */
 		if (params->user_workload) {
@@ -1205,9 +1219,9 @@ int timerlat_top_main(int argc, char *argv[])
 	timerlat_top_set_signals(params);
 
 	if (params->mode == TRACING_MODE_TRACEFS)
-		retval = timerlat_top_main_loop(top, record, params, &params_u);
+		retval = timerlat_top_main_loop(top, record, aa, params, &params_u);
 	else
-		retval = timerlat_top_bpf_main_loop(top, record, params, &params_u);
+		retval = timerlat_top_bpf_main_loop(top, record, aa, params, &params_u);
 
 	if (retval)
 		goto out_top;
@@ -1230,7 +1244,6 @@ int timerlat_top_main(int argc, char *argv[])
 		if (!params->no_aa)
 			timerlat_auto_analysis(params->stop_us, params->stop_total_us);
 
-		actions_perform(&params->actions);
 		return_value = FAILED;
 	} else if (params->aa_only) {
 		/*
-- 
2.49.0

[PATCH v2 5/9] rtla/timerlat: Add action on end feature

[Tomas Glozar]

Implement actions on end next to actions on threshold. A new option,
--on-end is added, parallel to --on-threshold. Instead of being
executed whenever a latency threshold is reached, it is executed at the
end of the measurement.

For example:

$ rtla timerlat hist -d 5s --on-end trace

will save the trace output at the end.

All actions supported by --on-threshold are also supported by --on-end,
except for continue, which does nothing with --on-end.

Signed-off-by: Tomas Glozar <tglozar@redhat.com>
---
 tools/tracing/rtla/src/timerlat.h      |  5 ++-
 tools/tracing/rtla/src/timerlat_hist.c | 44 +++++++++++++++++--------
 tools/tracing/rtla/src/timerlat_top.c  | 45 ++++++++++++++++++--------
 3 files changed, 65 insertions(+), 29 deletions(-)

diff --git a/tools/tracing/rtla/src/timerlat.h b/tools/tracing/rtla/src/timerlat.h
index d1fcf9a97621..bc55ed04fc96 100644
--- a/tools/tracing/rtla/src/timerlat.h
+++ b/tools/tracing/rtla/src/timerlat.h
@@ -48,7 +48,10 @@ struct timerlat_params {
 	struct sched_attr	sched_param;
 	struct trace_events	*events;
 	enum timerlat_tracing_mode mode;
-	struct actions actions;
+
+	struct actions threshold_actions;
+	struct actions end_actions;
+
 	union {
 		struct {
 			/* top only */
diff --git a/tools/tracing/rtla/src/timerlat_hist.c b/tools/tracing/rtla/src/timerlat_hist.c
index 4f13a8f92711..9baea1b251ed 100644
--- a/tools/tracing/rtla/src/timerlat_hist.c
+++ b/tools/tracing/rtla/src/timerlat_hist.c
@@ -758,6 +758,7 @@ static void timerlat_hist_usage(char *usage)
 		"	     --trace-buffer-size kB: set the per-cpu trace buffer size in kB",
 		"	     --deepest-idle-state n: only go down to idle state n on cpus used by timerlat to reduce exit from idle latency",
 		"	     --on-threshold <action>: define action to be executed at latency threshold, multiple are allowed",
+		"	     --on-end <action>: define action to be executed at measurement end, multiple are allowed",
 		NULL,
 	};
 
@@ -793,7 +794,8 @@ static struct timerlat_params
 	if (!params)
 		exit(1);
 
-	actions_init(&params->actions);
+	actions_init(&params->threshold_actions);
+	actions_init(&params->end_actions);
 
 	/* disabled by default */
 	params->dma_latency = -1;
@@ -846,6 +848,7 @@ static struct timerlat_params
 			{"trace-buffer-size",	required_argument,	0, '\3'},
 			{"deepest-idle-state",	required_argument,	0, '\4'},
 			{"on-threshold",	required_argument,	0, '\5'},
+			{"on-end",		required_argument,	0, '\6'},
 			{0, 0, 0, 0}
 		};
 
@@ -1038,7 +1041,14 @@ static struct timerlat_params
 			params->deepest_idle_state = get_llong_from_str(optarg);
 			break;
 		case '\5':
-			retval = actions_parse(&params->actions, optarg);
+			retval = actions_parse(&params->threshold_actions, optarg);
+			if (retval) {
+				err_msg("Invalid action %s\n", optarg);
+				exit(EXIT_FAILURE);
+			}
+			break;
+		case '\6':
+			retval = actions_parse(&params->end_actions, optarg);
 			if (retval) {
 				err_msg("Invalid action %s\n", optarg);
 				exit(EXIT_FAILURE);
@@ -1050,7 +1060,7 @@ static struct timerlat_params
 	}
 
 	if (trace_output)
-		actions_add_trace_output(&params->actions, trace_output);
+		actions_add_trace_output(&params->threshold_actions, trace_output);
 
 	if (geteuid()) {
 		err_msg("rtla needs root permission\n");
@@ -1077,7 +1087,8 @@ static struct timerlat_params
 	 * mixed mode
 	 */
 	if (params->mode == TRACING_MODE_BPF &&
-	    (params->actions.present[ACTION_TRACE_OUTPUT] || !params->no_aa))
+	    (params->threshold_actions.present[ACTION_TRACE_OUTPUT] ||
+	     params->end_actions.present[ACTION_TRACE_OUTPUT] || !params->no_aa))
 		params->mode = TRACING_MODE_MIXED;
 
 	return params;
@@ -1270,13 +1281,15 @@ int timerlat_hist_main(int argc, char *argv[])
 		}
 	}
 
-	if (params->actions.present[ACTION_TRACE_OUTPUT]) {
+	if (params->threshold_actions.present[ACTION_TRACE_OUTPUT] ||
+	    params->end_actions.present[ACTION_TRACE_OUTPUT]) {
 		record = osnoise_init_trace_tool("timerlat");
 		if (!record) {
 			err_msg("Failed to enable the trace instance\n");
 			goto out_free;
 		}
-		params->actions.trace_output_inst = record->trace.inst;
+		params->threshold_actions.trace_output_inst = record->trace.inst;
+		params->end_actions.trace_output_inst = record->trace.inst;
 
 		if (params->events) {
 			retval = trace_events_enable(&record->trace, params->events);
@@ -1342,7 +1355,7 @@ int timerlat_hist_main(int argc, char *argv[])
 	 * tracing while enabling other instances. The trace instance is the
 	 * one with most valuable information.
 	 */
-	if (params->actions.present[ACTION_TRACE_OUTPUT])
+	if (record)
 		trace_instance_start(&record->trace);
 	if (!params->no_aa)
 		trace_instance_start(&aa->trace);
@@ -1375,14 +1388,14 @@ int timerlat_hist_main(int argc, char *argv[])
 			}
 
 			if (osnoise_trace_is_off(tool, record)) {
-				actions_perform(&params->actions);
+				actions_perform(&params->threshold_actions);
 
-				if (!params->actions.continue_flag)
+				if (!params->threshold_actions.continue_flag)
 					/* continue flag not set, break */
 					break;
 
 				/* continue action reached, re-enable tracing */
-				if (params->actions.present[ACTION_TRACE_OUTPUT])
+				if (record)
 					trace_instance_start(&record->trace);
 				if (!params->no_aa)
 					trace_instance_start(&aa->trace);
@@ -1403,14 +1416,14 @@ int timerlat_hist_main(int argc, char *argv[])
 
 			if (!stop_tracing) {
 				/* Threshold overflow, perform actions on threshold */
-				actions_perform(&params->actions);
+				actions_perform(&params->threshold_actions);
 
-				if (!params->actions.continue_flag)
+				if (!params->threshold_actions.continue_flag)
 					/* continue flag not set, break */
 					break;
 
 				/* continue action reached, re-enable tracing */
-				if (params->actions.present[ACTION_TRACE_OUTPUT])
+				if (record)
 					trace_instance_start(&record->trace);
 				if (!params->no_aa)
 					trace_instance_start(&aa->trace);
@@ -1435,6 +1448,8 @@ int timerlat_hist_main(int argc, char *argv[])
 
 	timerlat_print_stats(params, tool);
 
+	actions_perform(&params->end_actions);
+
 	return_value = PASSED;
 
 	if (osnoise_trace_is_off(tool, record) && !stop_tracing) {
@@ -1464,7 +1479,8 @@ int timerlat_hist_main(int argc, char *argv[])
 	osnoise_destroy_tool(aa);
 	osnoise_destroy_tool(record);
 	osnoise_destroy_tool(tool);
-	actions_destroy(&params->actions);
+	actions_destroy(&params->threshold_actions);
+	actions_destroy(&params->end_actions);
 	if (params->mode != TRACING_MODE_TRACEFS)
 		timerlat_bpf_destroy();
 	free(params);
diff --git a/tools/tracing/rtla/src/timerlat_top.c b/tools/tracing/rtla/src/timerlat_top.c
index 60f9c78cb272..c80b81c0b4da 100644
--- a/tools/tracing/rtla/src/timerlat_top.c
+++ b/tools/tracing/rtla/src/timerlat_top.c
@@ -517,6 +517,7 @@ static void timerlat_top_usage(char *usage)
 		"	     --trace-buffer-size kB: set the per-cpu trace buffer size in kB",
 		"	     --deepest-idle-state n: only go down to idle state n on cpus used by timerlat to reduce exit from idle latency",
 		"	     --on-threshold <action>: define action to be executed at latency threshold, multiple are allowed",
+		"	     --on-end: define action to be executed at measurement end, multiple are allowed",
 		NULL,
 	};
 
@@ -552,7 +553,8 @@ static struct timerlat_params
 	if (!params)
 		exit(1);
 
-	actions_init(&params->actions);
+	actions_init(&params->threshold_actions);
+	actions_init(&params->end_actions);
 
 	/* disabled by default */
 	params->dma_latency = -1;
@@ -597,6 +599,7 @@ static struct timerlat_params
 			{"trace-buffer-size",	required_argument,	0, '7'},
 			{"deepest-idle-state",	required_argument,	0, '8'},
 			{"on-threshold",	required_argument,	0, '9'},
+			{"on-end",		required_argument,	0, '\1'},
 			{0, 0, 0, 0}
 		};
 
@@ -623,6 +626,7 @@ static struct timerlat_params
 
 			/* set trace */
 			trace_output = "timerlat_trace.txt";
+
 			break;
 		case '5':
 			/* it is here because it is similar to -a */
@@ -776,7 +780,14 @@ static struct timerlat_params
 			params->deepest_idle_state = get_llong_from_str(optarg);
 			break;
 		case '9':
-			retval = actions_parse(&params->actions, optarg);
+			retval = actions_parse(&params->threshold_actions, optarg);
+			if (retval) {
+				err_msg("Invalid action %s\n", optarg);
+				exit(EXIT_FAILURE);
+			}
+			break;
+		case '\1':
+			retval = actions_parse(&params->end_actions, optarg);
 			if (retval) {
 				err_msg("Invalid action %s\n", optarg);
 				exit(EXIT_FAILURE);
@@ -788,7 +799,7 @@ static struct timerlat_params
 	}
 
 	if (trace_output)
-		actions_add_trace_output(&params->actions, trace_output);
+		actions_add_trace_output(&params->threshold_actions, trace_output);
 
 	if (geteuid()) {
 		err_msg("rtla needs root permission\n");
@@ -812,7 +823,8 @@ static struct timerlat_params
 	 * mixed mode
 	 */
 	if (params->mode == TRACING_MODE_BPF &&
-	    (params->actions.present[ACTION_TRACE_OUTPUT] || !params->no_aa))
+	    (params->threshold_actions.present[ACTION_TRACE_OUTPUT] ||
+	     params->end_actions.present[ACTION_TRACE_OUTPUT] || !params->no_aa))
 		params->mode = TRACING_MODE_MIXED;
 
 	return params;
@@ -934,14 +946,14 @@ timerlat_top_main_loop(struct osnoise_tool *top,
 			timerlat_print_stats(params, top);
 
 		if (osnoise_trace_is_off(top, record)) {
-			actions_perform(&params->actions);
+			actions_perform(&params->threshold_actions);
 
-			if (!params->actions.continue_flag)
+			if (!params->threshold_actions.continue_flag)
 				/* continue flag not set, break */
 				break;
 
 			/* continue action reached, re-enable tracing */
-			if (params->actions.present[ACTION_TRACE_OUTPUT])
+			if (record)
 				trace_instance_start(&record->trace);
 			if (!params->no_aa)
 				trace_instance_start(&aa->trace);
@@ -993,14 +1005,14 @@ timerlat_top_bpf_main_loop(struct osnoise_tool *top,
 
 		if (wait_retval == 1) {
 			/* Stopping requested by tracer */
-			actions_perform(&params->actions);
+			actions_perform(&params->threshold_actions);
 
-			if (!params->actions.continue_flag)
+			if (!params->threshold_actions.continue_flag)
 				/* continue flag not set, break */
 				break;
 
 			/* continue action reached, re-enable tracing */
-			if (params->actions.present[ACTION_TRACE_OUTPUT])
+			if (record)
 				trace_instance_start(&record->trace);
 			if (!params->no_aa)
 				trace_instance_start(&aa->trace);
@@ -1128,13 +1140,15 @@ int timerlat_top_main(int argc, char *argv[])
 		}
 	}
 
-	if (params->actions.present[ACTION_TRACE_OUTPUT]) {
+	if (params->threshold_actions.present[ACTION_TRACE_OUTPUT] ||
+	    params->end_actions.present[ACTION_TRACE_OUTPUT]) {
 		record = osnoise_init_trace_tool("timerlat");
 		if (!record) {
 			err_msg("Failed to enable the trace instance\n");
 			goto out_free;
 		}
-		params->actions.trace_output_inst = record->trace.inst;
+		params->threshold_actions.trace_output_inst = record->trace.inst;
+		params->end_actions.trace_output_inst = record->trace.inst;
 
 		if (params->events) {
 			retval = trace_events_enable(&record->trace, params->events);
@@ -1201,7 +1215,7 @@ int timerlat_top_main(int argc, char *argv[])
 	 * tracing while enabling other instances. The trace instance is the
 	 * one with most valuable information.
 	 */
-	if (params->actions.present[ACTION_TRACE_OUTPUT])
+	if (record)
 		trace_instance_start(&record->trace);
 	if (!params->no_aa)
 		trace_instance_start(&aa->trace);
@@ -1236,6 +1250,8 @@ int timerlat_top_main(int argc, char *argv[])
 
 	timerlat_print_stats(params, top);
 
+	actions_perform(&params->end_actions);
+
 	return_value = PASSED;
 
 	if (osnoise_trace_is_off(top, record) && !stop_tracing) {
@@ -1276,7 +1292,8 @@ int timerlat_top_main(int argc, char *argv[])
 		osnoise_destroy_tool(aa);
 	osnoise_destroy_tool(record);
 	osnoise_destroy_tool(top);
-	actions_destroy(&params->actions);
+	actions_destroy(&params->threshold_actions);
+	actions_destroy(&params->end_actions);
 	if (params->mode != TRACING_MODE_TRACEFS)
 		timerlat_bpf_destroy();
 	free(params);
-- 
2.49.0

[PATCH v2 6/9] rtla/tests: Check rtla output with grep

[Tomas Glozar]

Add argument to the check command in the test suite that takes a regular
expression that the output of rtla command is checked against. This
allows testing for specific information in rtla output in addition
to checking the return value.

Two minor improvements are included: running rtla with "eval" so that
arguments with spaces can be passed to it via shell quotations, and
the stdout of pushd and popd is suppressed to clean up the test output.

Signed-off-by: Tomas Glozar <tglozar@redhat.com>
---
 tools/tracing/rtla/tests/engine.sh | 21 +++++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)

diff --git a/tools/tracing/rtla/tests/engine.sh b/tools/tracing/rtla/tests/engine.sh
index f2616a8e4179..64c5be4313de 100644
--- a/tools/tracing/rtla/tests/engine.sh
+++ b/tools/tracing/rtla/tests/engine.sh
@@ -11,7 +11,7 @@ test_begin() {
 reset_osnoise() {
 	# Reset osnoise options to default and remove any dangling instances created
 	# by improperly exited rtla runs.
-	pushd /sys/kernel/tracing || return 1
+	pushd /sys/kernel/tracing >/dev/null || return 1
 
 	# Remove dangling instances created by previous rtla run
 	echo 0 > tracing_thresh
@@ -35,11 +35,14 @@ reset_osnoise() {
 	echo 0 > stop_tracing_us
 	echo 1000 > timerlat_period_us
 
-	popd
+	popd >/dev/null
 }
 
 check() {
+	test_name=$0
+	tested_command=$1
 	expected_exitcode=${3:-0}
+	expected_output=$4
 	# Simple check: run rtla with given arguments and test exit code.
 	# If TEST_COUNT is set, run the test. Otherwise, just count.
 	ctr=$(($ctr + 1))
@@ -49,8 +52,16 @@ check() {
 		[ "$NO_RESET_OSNOISE" == 1 ] || reset_osnoise
 		# Run rtla; in case of failure, include its output as comment
 		# in the test results.
-		result=$(stdbuf -oL $TIMEOUT "$RTLA" $2 2>&1); exitcode=$?
-		if [ $exitcode -eq $expected_exitcode ]
+		result=$(eval stdbuf -oL $TIMEOUT "$RTLA" $2 2>&1); exitcode=$?
+		# Test if the results matches if requested
+		if [ -n "$expected_output" ]
+		then
+			grep -E "$expected_output" <<< "$result" > /dev/null; grep_result=$?
+		else
+			grep_result=0
+		fi
+
+		if [ $exitcode -eq $expected_exitcode ] && [ $grep_result -eq 0 ]
 		then
 			echo "ok $ctr - $1"
 		else
@@ -58,6 +69,8 @@ check() {
 			# Add rtla output and exit code as comments in case of failure
 			echo "$result" | col -b | while read line; do echo "# $line"; done
 			printf "#\n# exit code %s\n" $exitcode
+			[ -n "$expected_output" ] && \
+				printf "# Output match failed: \"%s\"\n" "$expected_output"
 		fi
 	fi
 }
-- 
2.49.0

[PATCH v2 7/9] rtla/tests: Add tests for actions

[Tomas Glozar]

Add a bunch of tests covering most of both --on-threshold and --on-end.
Parts sensitive to implementation of hist/top are tested for both.

Signed-off-by: Tomas Glozar <tglozar@redhat.com>
---
 tools/tracing/rtla/tests/timerlat.t | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/tools/tracing/rtla/tests/timerlat.t b/tools/tracing/rtla/tests/timerlat.t
index 579c12a85e8f..b354bacd78f8 100644
--- a/tools/tracing/rtla/tests/timerlat.t
+++ b/tools/tracing/rtla/tests/timerlat.t
@@ -18,6 +18,8 @@ fi
 for option in $no_bpf_options
 do
 export RTLA_NO_BPF=$option
+
+# Basic tests
 check "verify help page" \
 	"timerlat --help"
 check "verify -s/--stack" \
@@ -36,6 +38,32 @@ check "verify -c/--cpus" \
 	"timerlat hist -c 0 -d 30s"
 check "hist test in nanoseconds" \
 	"timerlat hist -i 2 -c 0 -n -d 30s" 2
+
+# Actions tests
+check "trace output through -t" \
+	"timerlat hist -T 2 -t" 2 "^  Saving trace to timerlat_trace.txt$"
+check "trace output through -t with custom filename" \
+	"timerlat hist -T 2 -t custom_filename.txt" 2 "^  Saving trace to custom_filename.txt$"
+check "trace output through -A trace" \
+	"timerlat hist -T 2 --on-threshold trace" 2 "^  Saving trace to timerlat_trace.txt$"
+check "trace output through -A trace with custom filename" \
+	"timerlat hist -T 2 --on-threshold trace,file=custom_filename.txt" 2 "^  Saving trace to custom_filename.txt$"
+check "exec command" \
+	"timerlat hist -T 2 --on-threshold shell,command='echo TestOutput'" 2 "^TestOutput$"
+check "multiple actions" \
+	"timerlat hist -T 2 --on-threshold shell,command='echo -n 1' --on-threshold shell,command='echo 2'" 2 "^12$"
+check "hist stop at failed action" \
+	"timerlat hist -T 2 --on-threshold shell,command='echo -n 1; false' --on-threshold shell,command='echo -n 2'" 2 "^1# RTLA timerlat histogram$"
+check "top stop at failed action" \
+	"timerlat top -T 2 --on-threshold shell,command='echo -n 1; false' --on-threshold shell,command='echo -n 2'" 2 "^1ALL"
+check "hist with continue" \
+	"timerlat hist -T 2 -d 1s --on-threshold shell,command='echo TestOutput' --on-threshold continue" 0 "^TestOutput$"
+check "top with continue" \
+	"timerlat top -q -T 2 -d 1s --on-threshold shell,command='echo TestOutput' --on-threshold continue" 0 "^TestOutput$"
+check "hist with trace output at end" \
+	"timerlat hist -d 1s --on-end trace" 0 "^  Saving trace to timerlat_trace.txt$"
+check "top with trace output at end" \
+	"timerlat top -d 1s --on-end trace" 0 "^  Saving trace to timerlat_trace.txt$"
 done
 
 test_end
-- 
2.49.0

[PATCH v2 8/9] rtla/tests: Limit duration to maximum of 10s

[Tomas Glozar]

Many of the original rtla tests included durations of 1 minute and 30
seconds. Experience has shown this is unnecessary, since 10 seconds as
waiting time for samples to appear.

Change duration of all rtla tests to at most 10 seconds. This speeds up
testing significantly.

Before:
$ make check
All tests successful.
Files=3, Tests=54, 536 wallclock secs
( 0.03 usr  0.00 sys + 20.31 cusr 22.02 csys = 42.36 CPU)
Result: PASS

After:
$ make check
...
All tests successful.
Files=3, Tests=54, 196 wallclock secs
( 0.03 usr  0.01 sys + 20.28 cusr 20.68 csys = 41.00 CPU)
Result: PASS

Signed-off-by: Tomas Glozar <tglozar@redhat.com>
---
 tools/tracing/rtla/tests/hwnoise.t  | 8 ++++----
 tools/tracing/rtla/tests/osnoise.t  | 4 ++--
 tools/tracing/rtla/tests/timerlat.t | 8 ++++----
 3 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/tools/tracing/rtla/tests/hwnoise.t b/tools/tracing/rtla/tests/hwnoise.t
index 5f71401a139e..448877564b8d 100644
--- a/tools/tracing/rtla/tests/hwnoise.t
+++ b/tools/tracing/rtla/tests/hwnoise.t
@@ -10,12 +10,12 @@ check "verify help page" \
 check "detect noise higher than one microsecond" \
 	"hwnoise -c 0 -T 1 -d 5s -q"
 check "set the automatic trace mode" \
-	"hwnoise -a 5 -d 30s" 2
+	"hwnoise -a 5 -d 10s" 2
 check "set scheduling param to the osnoise tracer threads" \
-	"hwnoise -P F:1 -c 0 -r 900000 -d 1M -q"
+	"hwnoise -P F:1 -c 0 -r 900000 -d 10s -q"
 check "stop the trace if a single sample is higher than 1 us" \
-	"hwnoise -s 1 -T 1 -t -d 30s" 2
+	"hwnoise -s 1 -T 1 -t -d 10s" 2
 check "enable a trace event trigger" \
-	"hwnoise -t -e osnoise:irq_noise trigger=\"hist:key=desc,duration:sort=desc,duration:vals=hitcount\" -d 1m"
+	"hwnoise -t -e osnoise:irq_noise trigger=\"hist:key=desc,duration:sort=desc,duration:vals=hitcount\" -d 10s"
 
 test_end
diff --git a/tools/tracing/rtla/tests/osnoise.t b/tools/tracing/rtla/tests/osnoise.t
index 44908fc01abf..6a4dfa31dc55 100644
--- a/tools/tracing/rtla/tests/osnoise.t
+++ b/tools/tracing/rtla/tests/osnoise.t
@@ -8,13 +8,13 @@ set_timeout 2m
 check "verify help page" \
 	"osnoise --help"
 check "verify the --priority/-P param" \
-	"osnoise top -P F:1 -c 0 -r 900000 -d 1M -q"
+	"osnoise top -P F:1 -c 0 -r 900000 -d 10s -q"
 check "verify the --stop/-s param" \
 	"osnoise top -s 30 -T 1 -t" 2
 check "verify the  --trace param" \
 	"osnoise hist -s 30 -T 1 -t" 2
 check "verify the --entries/-E param" \
-	"osnoise hist -P F:1 -c 0 -r 900000 -d 1M -b 10 -E 25"
+	"osnoise hist -P F:1 -c 0 -r 900000 -d 10s -b 10 -E 25"
 
 # Test setting default period by putting an absurdly high period
 # and stopping on threshold.
diff --git a/tools/tracing/rtla/tests/timerlat.t b/tools/tracing/rtla/tests/timerlat.t
index b354bacd78f8..2d59ee199c4d 100644
--- a/tools/tracing/rtla/tests/timerlat.t
+++ b/tools/tracing/rtla/tests/timerlat.t
@@ -25,9 +25,9 @@ check "verify help page" \
 check "verify -s/--stack" \
 	"timerlat top -s 3 -T 10 -t" 2
 check "verify -P/--priority" \
-	"timerlat top -P F:1 -c 0 -d 1M -q"
+	"timerlat top -P F:1 -c 0 -d 10s -q"
 check "test in nanoseconds" \
-	"timerlat top -i 2 -c 0 -n -d 30s" 2
+	"timerlat top -i 2 -c 0 -n -d 10s" 2
 check "set the automatic trace mode" \
 	"timerlat top -a 5 --dump-tasks" 2
 check "print the auto-analysis if hits the stop tracing condition" \
@@ -35,9 +35,9 @@ check "print the auto-analysis if hits the stop tracing condition" \
 check "disable auto-analysis" \
 	"timerlat top -s 3 -T 10 -t --no-aa" 2
 check "verify -c/--cpus" \
-	"timerlat hist -c 0 -d 30s"
+	"timerlat hist -c 0 -d 10s"
 check "hist test in nanoseconds" \
-	"timerlat hist -i 2 -c 0 -n -d 30s" 2
+	"timerlat hist -i 2 -c 0 -n -d 10s" 2
 
 # Actions tests
 check "trace output through -t" \
-- 
2.49.0

[PATCH v2 9/9] Documentation/rtla: Add actions feature

[Tomas Glozar]

Document both --on-threshold and --on-end, with examples.

Signed-off-by: Tomas Glozar <tglozar@redhat.com>
---
 .../tools/rtla/common_timerlat_options.rst    | 64 +++++++++++++++++++
 1 file changed, 64 insertions(+)

diff --git a/Documentation/tools/rtla/common_timerlat_options.rst b/Documentation/tools/rtla/common_timerlat_options.rst
index 10dc802f8d65..7854368f1827 100644
--- a/Documentation/tools/rtla/common_timerlat_options.rst
+++ b/Documentation/tools/rtla/common_timerlat_options.rst
@@ -55,3 +55,67 @@
         Set timerlat to run without workload, waiting for the user to dispatch a per-cpu
         task that waits for a new period on the tracing/osnoise/per_cpu/cpu$ID/timerlat_fd.
         See linux/tools/rtla/sample/timerlat_load.py for an example of user-load code.
+
+**--on-threshold** *action*
+
+        Defines an action to be executed when tracing is stopped on a latency threshold
+        specified by **-i/--irq** or **-T/--thread**.
+
+        Multiple --on-threshold actions may be specified, and they will be executed in
+        the order they are provided. If any action fails, subsequent actions in the list
+        will not be executed.
+
+        Supported actions are:
+
+        - *trace[,file=<filename>]*
+
+          Saves trace output, optionally taking a filename. Alternative to -t/--trace.
+          Note that nlike -t/--trace, specifying this multiple times will result in
+          the trace being saved multiple times.
+
+        - *signal,num=<sig>,pid=<pid>*
+
+          Sends signal to process. "parent" might be specified in place of pid to target
+          the parent process of rtla.
+
+        - *shell,command=<command>*
+
+          Execute shell command.
+
+        - *continue*
+
+          Continue tracing after actions are executed instead of stopping.
+
+        Example:
+
+        $ rtla timerlat -T 20 --on-threshold trace
+        --on-threshold shell,command="grep ipi_send timerlat_trace.txt"
+        --on-threshold signal,num=2,pid=parent
+
+        This will save a trace with the default filename "timerlat_trace.txt", print its
+        lines that contain the text "ipi_send" on standard output, and send signal 2
+        (SIGINT) to the parent process.
+
+        Performance Considerations:
+
+        For time-sensitive actions, it is recommended to run **rtla timerlat** with BPF
+        support and RT priority. Note that due to implementational limitations, actions
+        might be delayed up to one second after tracing is stopped if BPF mode is not
+        available or disabled.
+
+**--on-end** *action*
+
+        Defines an action to be executed at the end of **rtla timerlat** tracing.
+
+        Multiple --on-end actions can be specified, and they will be executed in the order
+        they are provided. If any action fails, subsequent actions in the list will not be
+        executed.
+
+        See the documentation for **--on-threshold** for the list of supported actions, with
+        the exception that *continue* has no effect.
+
+        Example:
+
+        $ rtla timerlat -d 5s --on-end trace
+
+        This runs rtla timerlat with default options and save trace output at the end.
-- 
2.49.0

Re: [PATCH v2 9/9] Documentation/rtla: Add actions feature

[Steven Rostedt]

On Thu, 26 Jun 2025 14:34:05 +0200
Tomas Glozar <tglozar@redhat.com> wrote:

> +        For time-sensitive actions, it is recommended to run **rtla timerlat** with BPF
> +        support and RT priority. Note that due to implementational limitations, actions
> +        might be delayed up to one second after tracing is stopped if BPF mode is not
> +        available or disabled.
> +

I'm curious to what is looked for for triggering an action. We can poll on
events and get woken when they are triggered. It may be possible to add
even more ways to wake a task waiting for something to happen.

-- Steve

Re: [PATCH v2 9/9] Documentation/rtla: Add actions feature

[Tomas Glozar]

út 22. 7. 2025 v 0:35 odesílatel Steven Rostedt <rostedt@goodmis.org> napsal:
>
> I'm curious to what is looked for for triggering an action. We can poll on
> events and get woken when they are triggered. It may be possible to add
> even more ways to wake a task waiting for something to happen.
>

Threshold actions are triggered immediately after a sample over the
set threshold is detected by rtla. For BPF mode, this happens almost
right after the sample is processed in the BPF program and the
scheduler gets to waking up rtla following a BPF ringbuffer write.
There is only a short delay (up to tens of microseconds) because the
BPF helper defers the wake-up into irq_work.

For non-BPF mode, rtla periodically pulls samples from tracefs, when
it does that, it also checks whether tracing has been turned off. If
yes, that means there was a threshold overflow, and actions are
triggered. Since the period for that is currently set to 1 second, the
action might be delayed up to one second from the threshold occurring,
That delay might be a problem if you need to collect a lot of data
from a ringbuffer in the action, e.g. global Intel PT data collection
for precise troubleshooting of difficult latencies.

Of course, this is just an implementational limitation of the timerlat
tracer. If timerlat had an event (like osnoise's "sample_threshold")
triggered on threshold overflow and if it is possible to wait on it
even without BPF, rtla could wait on that for both BPF and non-BPF
mode instead of what it is currently doing.

Tomas

Re: [PATCH v2 9/9] Documentation/rtla: Add actions feature

[Steven Rostedt]

On Tue, 22 Jul 2025 09:03:24 +0200
Tomas Glozar <tglozar@redhat.com> wrote:

> Of course, this is just an implementational limitation of the timerlat
> tracer. If timerlat had an event (like osnoise's "sample_threshold")
> triggered on threshold overflow and if it is possible to wait on it
> even without BPF, rtla could wait on that for both BPF and non-BPF
> mode instead of what it is currently doing.

Right. Is this something you may want?

-- Steve

Re: [PATCH v2 9/9] Documentation/rtla: Add actions feature

[Tomas Glozar]

út 22. 7. 2025 v 17:30 odesílatel Steven Rostedt <rostedt@goodmis.org> napsal:
>
> On Tue, 22 Jul 2025 09:03:24 +0200
> Tomas Glozar <tglozar@redhat.com> wrote:
>
> > Of course, this is just an implementational limitation of the timerlat
> > tracer. If timerlat had an event (like osnoise's "sample_threshold")
> > triggered on threshold overflow and if it is possible to wait on it
> > even without BPF, rtla could wait on that for both BPF and non-BPF
> > mode instead of what it is currently doing.
>
> Right. Is this something you may want?
>

I don't think it is that important. Non-BPF mode is mostly as a
fallback for users of rtla on older kernels which don't have the
osnoise:timerlat_sample trace event. Those are (I assume) mostly users
of LTS distributions who run newer rtla from a container. Adding a new
event wouldn't help in their case.

The only users who would benefit from that are those who don't have
BPF or libbpf. If there is interest from using low-latency actions on
threshold in such settings, I'm not against implementing a threshold
overflow tracepoint and supporting it in rtla for triggering actions
on threshold.

Tomas