Re: [PATCH] perf stat: fix csv mode column output for non-cgroup events

From: Arnaldo Carvalho de Melo
Date: Wed Nov 21 2018 - 22:58:19 EST


Em Wed, Nov 07, 2018 at 02:50:45AM -0800, Stephane Eranian escreveu:
> When using the -x option, perf stat prints csv-style output
> with one event per line. For each event, it prints the count,
> the unit, the event name, the cgroup, and a bunch of other event
> specific fields (such as insn per cycles).
>
> When you use csv-style mode, you expect a normalized output where
> each event is printed with the same number of fields regardless of
> what it is so it can easily be imported into a spreadsheet or parsed.
> For instance, if an event does not have a unit, then print an empty field
> for it. Although this approach was implemented for the unit, it was not
> for the cgroup. When mixing cgroup and non-cgroup events, then non-cgroup
> events would not show an empty field, instead the next field was printed,
> make columns not line up correctly.
>
> This patch fixes the cgroup output issues by forcing an empty field
> for non-cgroup events as soon as one event has cgroup.

Looks sane, that nr_cgroups global variable at some point has to go to
the evlist, but that is not introduced by this patch, Jiri, are you ok
with it as well?

- Arnaldo

> Before:
> <not counted> @ @cycles @foo @ 0 @100.00@@
> 2531614 @ @cycles @6420922@xxxxxx@ @
>
> foo cgroup lines up with time_running!
>
> After:
> <not counted> @ @cycles @foo @0 @100.00@@
> 2594834 @ @cycles @ @5287372 @100.00@@
>
> Fields line up.
>
> Signed-off-by: Stephane Eranian <eranian@xxxxxxxxxx>
> ---
> tools/perf/util/stat-display.c | 16 +++++++++++-----
> 1 file changed, 11 insertions(+), 5 deletions(-)
>
> diff --git a/tools/perf/util/stat-display.c b/tools/perf/util/stat-display.c
> index e7b4c44ebb62..665ee374fc01 100644
> --- a/tools/perf/util/stat-display.c
> +++ b/tools/perf/util/stat-display.c
> @@ -59,6 +59,15 @@ static void print_noise(struct perf_stat_config *config,
> print_noise_pct(config, stddev_stats(&ps->res_stats[0]), avg);
> }
>
> +static void print_cgroup(struct perf_stat_config *config, struct perf_evsel *evsel)
> +{
> + if (nr_cgroups) {
> + const char *cgrp_name = evsel->cgrp ? evsel->cgrp->name : "";
> + fprintf(config->output, "%s%s", config->csv_sep, cgrp_name);
> + }
> +}
> +
> +
> static void aggr_printout(struct perf_stat_config *config,
> struct perf_evsel *evsel, int id, int nr)
> {
> @@ -336,8 +345,7 @@ static void abs_printout(struct perf_stat_config *config,
>
> fprintf(output, "%-*s", config->csv_output ? 0 : 25, perf_evsel__name(evsel));
>
> - if (evsel->cgrp)
> - fprintf(output, "%s%s", config->csv_sep, evsel->cgrp->name);
> + print_cgroup(config, evsel);
> }
>
> static bool is_mixed_hw_group(struct perf_evsel *counter)
> @@ -431,9 +439,7 @@ static void printout(struct perf_stat_config *config, int id, int nr,
> config->csv_output ? 0 : -25,
> perf_evsel__name(counter));
>
> - if (counter->cgrp)
> - fprintf(config->output, "%s%s",
> - config->csv_sep, counter->cgrp->name);
> + print_cgroup(config, counter);
>
> if (!config->csv_output)
> pm(config, &os, NULL, NULL, "", 0);
> --
> 2.7.4