Re: [PATCH v3 5/5] perf evlist: Add --trace-fields option to show trace fields

Arnaldo Carvalho de Melo
2016-01-06T23:29:57Z

Em Thu, Jan 07, 2016 at 08:21:44AM +0900, Namhyung Kim escreveu:
> On Wed, Jan 06, 2016 at 08:10:51PM -0300, Arnaldo Carvalho de Melo wrote:
> > Em Wed, Jan 06, 2016 at 09:55:01AM +0900, Namhyung Kim escreveu:
> > > To use dynamic sort keys, it might be good to add an option to see the
> > > list of field names.
> > >
> > > $ perf evlist -i perf.data.sched
> > > sched:sched_switch
> > > sched:sched_stat_wait
> > > sched:sched_stat_sleep
> > > sched:sched_stat_iowait
> > > sched:sched_stat_runtime
> > > sched:sched_process_fork
> > > sched:sched_wakeup
> > > sched:sched_wakeup_new
> > > sched:sched_migrate_task
> > > # Tip: use 'perf evlist --trace-fields' to show fields for tracepoint events
> >
> > Ok, almost there, question is: if I ask explicitely for
> > "--trace-fields", why should we have the "trace_fields=" in all lines,
> > instead of just:
> >
> >
> > $ perf evlist -i perf.data.sched --trace-fields
> > sched:sched_switch: prev_comm,prev_pid,prev_prio,prev_state,next_comm,next_pid,next_prio
> > sched:sched_stat_wait: comm,pid,delay
> >
> > ?
>
> I made it to work with other options too, like 'perf evlist --freq --trace-fields'.
> In that case you may want to see it. :)

I see... And then you want to show those at the same time... Would you
have an use case for that? Or would it be better to make them mutually
exclusive? /me unsure...

- Arnaldo

> Thanks,
> Namhyung
>
>
> >
> > I like the lack of spaces after commans, this way we can double click
> > and select the whole list, then edit it, etc.
> >
> > - Arnaldo
> >
> > > $ perf evlist -i perf.data.sched --trace-fields
> > > sched:sched_switch: trace_fields=prev_comm,prev_pid,prev_prio,prev_state,next_comm,next_pid,next_prio
> > > sched:sched_stat_wait: trace_fields=comm,pid,delay
> > > sched:sched_stat_sleep: trace_fields=comm,pid,delay
> > > sched:sched_stat_iowait: trace_fields=comm,pid,delay
> > > sched:sched_stat_runtime: trace_fields=comm,pid,runtime,vruntime
> > > sched:sched_process_fork: trace_fields=parent_comm,parent_pid,child_comm,child_pid
> > > sched:sched_wakeup: trace_fields=comm,pid,prio,success,target_cpu
> > > sched:sched_wakeup_new: trace_fields=comm,pid,prio,success,target_cpu
> > > sched:sched_migrate_task: trace_fields=comm,pid,prio,orig_cpu,dest_cpu
> > >
> > > Signed-off-by: Namhyung Kim <namhyung@kernel.org>
> > > ---
> > > tools/perf/Documentation/perf-evlist.txt | 3 +++
> > > tools/perf/builtin-evlist.c | 11 ++++++++++-
> > > tools/perf/util/evsel.c | 23 +++++++++++++++++++++++
> > > tools/perf/util/evsel.h | 1 +
> > > 4 files changed, 37 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/tools/perf/Documentation/perf-evlist.txt b/tools/perf/Documentation/perf-evlist.txt
> > > index 1ceb3700ffbb..6f7200fb85cf 100644
> > > --- a/tools/perf/Documentation/perf-evlist.txt
> > > +++ b/tools/perf/Documentation/perf-evlist.txt
> > > @@ -32,6 +32,9 @@ OPTIONS
> > > --group::
> > > Show event group information.
> > >
> > > +--trace-fields::
> > > + Show tracepoint field names.
> > > +
> > > SEE ALSO
> > > --------
> > > linkperf:perf-record[1], linkperf:perf-list[1],
> > > diff --git a/tools/perf/builtin-evlist.c b/tools/perf/builtin-evlist.c
> > > index 08a7d36a2cf8..8a31f511e1a0 100644
> > > --- a/tools/perf/builtin-evlist.c
> > > +++ b/tools/perf/builtin-evlist.c
> > > @@ -26,14 +26,22 @@ static int __cmd_evlist(const char *file_name, struct perf_attr_details *details
> > > .mode = PERF_DATA_MODE_READ,
> > > .force = details->force,
> > > };
> > > + bool has_tracepoint = false;
> > >
> > > session = perf_session__new(&file, 0, NULL);
> > > if (session == NULL)
> > > return -1;
> > >
> > > - evlist__for_each(session->evlist, pos)
> > > + evlist__for_each(session->evlist, pos) {
> > > perf_evsel__fprintf(pos, details, stdout);
> > >
> > > + if (pos->attr.type == PERF_TYPE_TRACEPOINT)
> > > + has_tracepoint = true;
> > > + }
> > > +
> > > + if (has_tracepoint && !details->trace_fields)
> > > + printf("# Tip: use 'perf evlist --trace-fields' to show fields for tracepoint events\n");
> > > +
> > > perf_session__delete(session);
> > > return 0;
> > > }
> > > @@ -49,6 +57,7 @@ int cmd_evlist(int argc, const char **argv, const char *prefix __maybe_unused)
> > > OPT_BOOLEAN('g', "group", &details.event_group,
> > > "Show event group information"),
> > > OPT_BOOLEAN('f', "force", &details.force, "don't complain, do it"),
> > > + OPT_BOOLEAN(0, "trace-fields", &details.trace_fields, "Show tracepoint fields"),
> > > OPT_END()
> > > };
> > > const char * const evlist_usage[] = {
> > > diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
> > > index 544e4400de13..b7822c98fcca 100644
> > > --- a/tools/perf/util/evsel.c
> > > +++ b/tools/perf/util/evsel.c
> > > @@ -2298,6 +2298,29 @@ int perf_evsel__fprintf(struct perf_evsel *evsel,
> > > printed += comma_fprintf(fp, &first, " %s=%" PRIu64,
> > > term, (u64)evsel->attr.sample_freq);
> > > }
> > > +
> > > + if (details->trace_fields) {
> > > + struct format_field *field;
> > > +
> > > + if (evsel->attr.type != PERF_TYPE_TRACEPOINT) {
> > > + printed += comma_fprintf(fp, &first, " (not a tracepoint)");
> > > + goto out;
> > > + }
> > > +
> > > + field = evsel->tp_format->format.fields;
> > > + if (field == NULL) {
> > > + printed += comma_fprintf(fp, &first, " (no trace field)");
> > > + goto out;
> > > + }
> > > +
> > > + printed += comma_fprintf(fp, &first, " trace_fields=%s", field->name);
> > > +
> > > + field = field->next;
> > > + while (field) {
> > > + printed += comma_fprintf(fp, &first, "%s", field->name);
> > > + field = field->next;
> > > + }
> > > + }
> > > out:
> > > fputc('\n', fp);
> > > return ++printed;
> > > diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
> > > index 5ded1fc0341e..8e75434bd01c 100644
> > > --- a/tools/perf/util/evsel.h
> > > +++ b/tools/perf/util/evsel.h
> > > @@ -369,6 +369,7 @@ struct perf_attr_details {
> > > bool verbose;
> > > bool event_group;
> > > bool force;
> > > + bool trace_fields;
> > > };
> > >
> > > int perf_evsel__fprintf(struct perf_evsel *evsel,
> > > --
> > > 2.6.4