Re: [PATCH v2 5/5] perf evlist: Add -T/--trace option to show trace fields

[Namhyung Kim <namhyung@kernel.org>]

On Tue, Jan 05, 2016 at 07:23:33PM -0300, Arnaldo Carvalho de Melo wrote:
> Em Tue, Jan 05, 2016 at 07:58:38PM +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 -T -i perf.data.sched
> 
> Humm, I think here we should just use --trace_fields, like what appears
> in the output for each line below, and also as is the case for the '-s
> trace_fields' case, ok?

OK

> 
> With:
> 
>   $ . ~/git/linux/tools/perf/perf-completion.sh 
>   [acme@zoo linux]$ perf evlist --
>   --force    --freq     --group    --input    --verbose  
>   [acme@zoo linux]$ perf evlist --
> 
> We can autocomplete it from --t<TAB> anyway :)
> 
> Unsure about '-T', perhaps this is so specialized, that can remain with
> just the long option?

OK

> 
> Perhaps we can add a tip, when we run:
> 
>   perf evlist
> 
> And there are tracepoint events, something like:
> 
>   perf evlist -v
>   sched:sched_switch ...
>   # Tip use 'perf evlist --trace_fields' to show fields for events such
>   # as "sched:sched_switch"

OK, it'd display this only the evlist has tracepoints.  How about this oneliner?

  # Tip: use 'perf evlist --trace_fields' to show fields for tracepoint events

Thanks,
Namhyung


> 
> - Arnaldo
> 
> >   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
> > 
> > Acked-by: Jiri Olsa <jolsa@kernel.org>
> > Signed-off-by: Namhyung Kim <namhyung@kernel.org>
> > ---
> >  tools/perf/Documentation/perf-evlist.txt |  4 ++++
> >  tools/perf/builtin-evlist.c              |  1 +
> >  tools/perf/util/evsel.c                  | 23 +++++++++++++++++++++++
> >  tools/perf/util/evsel.h                  |  1 +
> >  4 files changed, 29 insertions(+)
> > 
> > diff --git a/tools/perf/Documentation/perf-evlist.txt b/tools/perf/Documentation/perf-evlist.txt
> > index 1ceb3700ffbb..b0d99c276cf5 100644
> > --- a/tools/perf/Documentation/perf-evlist.txt
> > +++ b/tools/perf/Documentation/perf-evlist.txt
> > @@ -32,6 +32,10 @@ OPTIONS
> >  --group::
> >  	Show event group information.
> >  
> > +-T::
> > +--trace::
> > +	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..2820bb2d8cf8 100644
> > --- a/tools/perf/builtin-evlist.c
> > +++ b/tools/perf/builtin-evlist.c
> > @@ -49,6 +49,7 @@ 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('T', "trace", &details.trace, "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..174d0029e038 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) {
> > +		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..9b36dd584d4a 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;
> >  };
> >  
> >  int perf_evsel__fprintf(struct perf_evsel *evsel,
> > -- 
> > 2.6.4