From 761916fd02c2525139aca957b8a53fda1d8b3616 Mon Sep 17 00:00:00 2001 From: Daniel Bristot de Oliveira Date: Wed, 2 Mar 2022 20:01:36 +0100 Subject: rtla/trace: Save event histogram output to a file 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. Link: https://lkml.kernel.org/r/b5c906af31d4e022ffe87fb0848fac5c089087c8.1646247211.git.bristot@kernel.org Cc: Daniel Bristot de Oliveira Cc: Clark Williams Cc: Juri Lelli Cc: Jonathan Corbet Signed-off-by: Daniel Bristot de Oliveira Signed-off-by: Steven Rostedt (Google) --- 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 **. For further information about event filtering see https://www.kernel.org/doc/html/latest/trace/events.html#event-filtering. **--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 -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, -- cgit v1.2.3