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

[Arnaldo Carvalho de Melo <acme@kernel.org>]

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?

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?

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"

- 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