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

[Arnaldo Carvalho de Melo]

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 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@xxxxxxxxxx>
> ---
>  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
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