diff options
| -rw-r--r-- | Documentation/trace/histogram.rst | 54 | ||||
| -rw-r--r-- | kernel/trace/trace.c | 2 | ||||
| -rw-r--r-- | kernel/trace/trace_events_hist.c | 42 |
3 files changed, 76 insertions, 22 deletions
diff --git a/Documentation/trace/histogram.rst b/Documentation/trace/histogram.rst index 79476c906b1a..0ea59d45aef1 100644 --- a/Documentation/trace/histogram.rst +++ b/Documentation/trace/histogram.rst @@ -1873,31 +1873,45 @@ The available handlers are: The available actions are: - - <synthetic_event_name>(param list) - generate synthetic event + - trace(<synthetic_event_name>,param list) - generate synthetic event - save(field,...) - save current event fields - snapshot() - snapshot the trace buffer The following commonly-used handler.action pairs are available: - - onmatch(matching.event).<synthetic_event_name>(param list) + - onmatch(matching.event).trace(<synthetic_event_name>,param list) - The 'onmatch(matching.event).<synthetic_event_name>(params)' hist - trigger action is invoked whenever an event matches and the - histogram entry would be added or updated. It causes the named - synthetic event to be generated with the values given in the + The 'onmatch(matching.event).trace(<synthetic_event_name>,param + list)' hist trigger action is invoked whenever an event matches + and the histogram entry would be added or updated. It causes the + named synthetic event to be generated with the values given in the 'param list'. The result is the generation of a synthetic event that consists of the values contained in those variables at the - time the invoking event was hit. - - The 'param list' consists of one or more parameters which may be - either variables or fields defined on either the 'matching.event' - or the target event. The variables or fields specified in the - param list may be either fully-qualified or unqualified. If a - variable is specified as unqualified, it must be unique between - the two events. A field name used as a param can be unqualified - if it refers to the target event, but must be fully qualified if - it refers to the matching event. A fully-qualified name is of the - form 'system.event_name.$var_name' or 'system.event_name.field'. + time the invoking event was hit. For example, if the synthetic + event name is 'wakeup_latency', a wakeup_latency event is + generated using onmatch(event).trace(wakeup_latency,arg1,arg2). + + There is also an equivalent alternative form available for + generating synthetic events. In this form, the synthetic event + name is used as if it were a function name. For example, using + the 'wakeup_latency' synthetic event name again, the + wakeup_latency event would be generated by invoking it as if it + were a function call, with the event field values passed in as + arguments: onmatch(event).wakeup_latency(arg1,arg2). The syntax + for this form is: + + onmatch(matching.event).<synthetic_event_name>(param list) + + In either case, the 'param list' consists of one or more + parameters which may be either variables or fields defined on + either the 'matching.event' or the target event. The variables or + fields specified in the param list may be either fully-qualified + or unqualified. If a variable is specified as unqualified, it + must be unique between the two events. A field name used as a + param can be unqualified if it refers to the target event, but + must be fully qualified if it refers to the matching event. A + fully-qualified name is of the form 'system.event_name.$var_name' + or 'system.event_name.field'. The 'matching.event' specification is simply the fully qualified event name of the event that matches the target event for the @@ -1928,6 +1942,12 @@ The following commonly-used handler.action pairs are available: wakeup_new_test($testpid) if comm=="cyclictest"' >> \ /sys/kernel/debug/tracing/events/sched/sched_wakeup_new/trigger + Or, equivalently, using the 'trace' keyword syntax: + + # echo 'hist:keys=$testpid:testpid=pid:onmatch(sched.sched_wakeup_new).\ + trace(wakeup_new_test,$testpid) if comm=="cyclictest"' >> \ + /sys/kernel/debug/tracing/events/sched/sched_wakeup_new/trigger + Creating and displaying a histogram based on those events is now just a matter of using the fields and new synthetic event in the tracing/events/synthetic directory, as usual:: diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index be6779f963c6..0460cc0f28fd 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -4918,7 +4918,7 @@ static const char readme_msg[] = "\t onmax(var) - invoke if var exceeds current max\n" "\t onchange(var) - invoke action if var changes\n\n" "\t The available actions are:\n\n" - "\t <synthetic_event>(param list) - generate synthetic event\n" + "\t trace(<synthetic_event>,param list) - generate synthetic event\n" "\t save(field,...) - save current event fields\n" #ifdef CONFIG_TRACER_SNAPSHOT "\t snapshot() - snapshot the trace buffer\n" diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index 2f3323ca9d24..66386ba1425f 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -419,6 +419,8 @@ struct action_data { */ unsigned int var_ref_idx; struct synth_event *synth_event; + bool use_trace_keyword; + char *synth_event_name; union { struct { @@ -3700,6 +3702,8 @@ static void action_data_destroy(struct action_data *data) if (data->synth_event) data->synth_event->ref--; + kfree(data->synth_event_name); + kfree(data); } @@ -3781,6 +3785,7 @@ static int track_data_create(struct hist_trigger_data *hist_data, static int parse_action_params(char *params, struct action_data *data) { char *param, *saved_param; + bool first_param = true; int ret = 0; while (params) { @@ -3809,6 +3814,13 @@ static int parse_action_params(char *params, struct action_data *data) goto out; } + if (first_param && data->use_trace_keyword) { + data->synth_event_name = saved_param; + first_param = false; + continue; + } + first_param = false; + data->params[data->n_params++] = saved_param; } out: @@ -3886,6 +3898,9 @@ static int action_parse(char *str, struct action_data *data, } else { char *params = strsep(&str, ")"); + if (str_has_prefix(action_name, "trace")) + data->use_trace_keyword = true; + if (params) { ret = parse_action_params(params, data); if (ret) @@ -4088,13 +4103,19 @@ static int trace_action_create(struct hist_trigger_data *hist_data, unsigned int i, var_ref_idx; unsigned int field_pos = 0; struct synth_event *event; + char *synth_event_name; int ret = 0; lockdep_assert_held(&event_mutex); - event = find_synth_event(data->action_name); + if (data->use_trace_keyword) + synth_event_name = data->synth_event_name; + else + synth_event_name = data->action_name; + + event = find_synth_event(synth_event_name); if (!event) { - hist_err("trace action: Couldn't find synthetic event: ", data->action_name); + hist_err("trace action: Couldn't find synthetic event: ", synth_event_name); return -EINVAL; } @@ -4841,8 +4862,10 @@ static void print_action_spec(struct seq_file *m, seq_puts(m, ","); } } else if (data->action == ACTION_TRACE) { + if (data->use_trace_keyword) + seq_printf(m, "%s", data->synth_event_name); for (i = 0; i < data->n_params; i++) { - if (i) + if (i || data->use_trace_keyword) seq_puts(m, ","); seq_printf(m, "%s", data->params[i]); } @@ -4890,6 +4913,7 @@ static bool actions_match(struct hist_trigger_data *hist_data, for (i = 0; i < hist_data->n_actions; i++) { struct action_data *data = hist_data->actions[i]; struct action_data *data_test = hist_data_test->actions[i]; + char *action_name, *action_name_test; if (data->handler != data_test->handler) return false; @@ -4904,7 +4928,17 @@ static bool actions_match(struct hist_trigger_data *hist_data, return false; } - if (strcmp(data->action_name, data_test->action_name) != 0) + if (data->use_trace_keyword) + action_name = data->synth_event_name; + else + action_name = data->action_name; + + if (data_test->use_trace_keyword) + action_name_test = data_test->synth_event_name; + else + action_name_test = data_test->action_name; + + if (strcmp(action_name, action_name_test) != 0) return false; if (data->handler == HANDLER_ONMATCH) { |