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

Arnaldo Carvalho de Melo
2016-01-06T23:10:57Z

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@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