The hist: trigger generates a histogram in the file sys/event/hist.
If the hist: trigger is used, automatically save the histogram output of
the event sys:event in the sys_event_hist.txt file.
Cc: Daniel Bristot de Oliveira <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Signed-off-by: Daniel Bristot de Oliveira <[email protected]>
---
Documentation/tools/rtla/common_options.rst | 10 +++-
tools/tracing/rtla/src/trace.c | 53 +++++++++++++++++++++
2 files changed, 62 insertions(+), 1 deletion(-)
diff --git a/Documentation/tools/rtla/common_options.rst b/Documentation/tools/rtla/common_options.rst
index afd45bae821f..af76df6205d4 100644
--- a/Documentation/tools/rtla/common_options.rst
+++ b/Documentation/tools/rtla/common_options.rst
@@ -23,7 +23,15 @@
Filter the previous **-e** *sys:event* event with *<filter>*. For further information about event filtering see https://www.kernel.org/doc/html/latest/trace/events.html#event-filtering.
**--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.
+ Enable a trace event trigger to the previous **-e** *sys:event*.
+ If the *hist:* trigger is activated, the output histogram will be automatically saved to a file named *system_event_hist.txt*.
+ For example, the command:
+
+ rtla <command> <mode> -t -e osnoise:irq_noise --trigger="hist:key=desc,duration/1000:sort=desc,duration/1000:vals=hitcount"
+
+ Will automatically save the content of the histogram associated to *osnoise:irq_noise* event in *osnoise_irq_noise_hist.txt*.
+
+ 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*
diff --git a/tools/tracing/rtla/src/trace.c b/tools/tracing/rtla/src/trace.c
index ef44bab0c404..8249ec4d77cc 100644
--- a/tools/tracing/rtla/src/trace.c
+++ b/tools/tracing/rtla/src/trace.c
@@ -296,6 +296,57 @@ static void trace_event_disable_filter(struct trace_instance *instance,
tevent->event ? : "*", tevent->filter);
}
+/*
+ * trace_event_save_hist - save the content of an event hist
+ *
+ * If the trigger is a hist: one, save the content of the hist file.
+ */
+static void trace_event_save_hist(struct trace_instance *instance,
+ struct trace_events *tevent)
+{
+ int retval, index, out_fd;
+ mode_t mode = 0644;
+ char path[1024];
+ char *hist;
+
+ if (!tevent)
+ return;
+
+ /* trigger enables hist */
+ if (!tevent->trigger)
+ return;
+
+ /* is this a hist: trigger? */
+ retval = strncmp(tevent->trigger, "hist:", strlen("hist:"));
+ if (retval)
+ return;
+
+ snprintf(path, 1024, "%s_%s_hist.txt", tevent->system, tevent->event);
+
+ printf(" Saving event %s:%s hist to %s\n", tevent->system, tevent->event, path);
+
+ out_fd = creat(path, mode);
+ if (out_fd < 0) {
+ err_msg(" Failed to create %s output file\n", path);
+ return;
+ }
+
+ hist = tracefs_event_file_read(instance->inst, tevent->system, tevent->event, "hist", 0);
+ if (!hist) {
+ err_msg(" Failed to read %s:%s hist file\n", tevent->system, tevent->event);
+ goto out_close;
+ }
+
+ index = 0;
+ do {
+ index += write(out_fd, &hist[index], strlen(hist) - index);
+ } while (index < strlen(hist));
+
+ free(hist);
+out_close:
+ close(out_fd);
+}
+
/*
* trace_event_disable_trigger - disable an event trigger
*/
@@ -314,6 +365,8 @@ static void trace_event_disable_trigger(struct trace_instance *instance,
debug_msg("Disabling %s:%s trigger %s\n", tevent->system,
tevent->event ? : "*", tevent->trigger);
+ trace_event_save_hist(instance, tevent);
+
snprintf(trigger, 1024, "!%s\n", tevent->trigger);
retval = tracefs_event_file_write(instance->inst, tevent->system,
--
2.34.1