[05/15] perf stat: Remove prefix argument in print_metric_headers()

Message ID 20221123180208.2068936-6-namhyung@kernel.org
State New
Headers
Series perf stat: Improve perf stat output (v2) |

Commit Message

Namhyung Kim Nov. 23, 2022, 6:01 p.m. UTC
  It always passes a whitespace to the function, thus we can just add it to the
function body.  Furthermore, it's only used in the normal output mode.

Well, actually CSV used it but it doesn't need to since we don't care about the
indentation or alignment in the CSV output.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
 tools/perf/util/stat-display.c | 26 ++++++++++----------------
 1 file changed, 10 insertions(+), 16 deletions(-)
  

Comments

Ian Rogers Nov. 23, 2022, 11:23 p.m. UTC | #1
On Wed, Nov 23, 2022 at 10:02 AM Namhyung Kim <namhyung@kernel.org> wrote:
>
> It always passes a whitespace to the function, thus we can just add it to the
> function body.  Furthermore, it's only used in the normal output mode.
>
> Well, actually CSV used it but it doesn't need to since we don't care about the
> indentation or alignment in the CSV output.
>
> Signed-off-by: Namhyung Kim <namhyung@kernel.org>

Acked-by: Ian Rogers <irogers@google.com>

Thanks,
Ian

> ---
>  tools/perf/util/stat-display.c | 26 ++++++++++----------------
>  1 file changed, 10 insertions(+), 16 deletions(-)
>
> diff --git a/tools/perf/util/stat-display.c b/tools/perf/util/stat-display.c
> index 744b7a40f59a..deed6ccf072f 100644
> --- a/tools/perf/util/stat-display.c
> +++ b/tools/perf/util/stat-display.c
> @@ -996,10 +996,9 @@ static void print_no_aggr_metric(struct perf_stat_config *config,
>  }
>
>  static void print_metric_headers_std(struct perf_stat_config *config,
> -                                    const char *prefix, bool no_indent)
> +                                    bool no_indent)
>  {
> -       if (prefix)
> -               fprintf(config->output, "%s", prefix);
> +       fputc(' ', config->output);
>
>         if (!no_indent) {
>                 int len = aggr_header_lens[config->aggr_mode];
> @@ -1012,11 +1011,8 @@ static void print_metric_headers_std(struct perf_stat_config *config,
>  }
>
>  static void print_metric_headers_csv(struct perf_stat_config *config,
> -                                    const char *prefix,
>                                      bool no_indent __maybe_unused)
>  {
> -       if (prefix)
> -               fprintf(config->output, "%s", prefix);
>         if (config->interval)
>                 fputs("time,", config->output);
>         if (!config->iostat_run)
> @@ -1024,7 +1020,6 @@ static void print_metric_headers_csv(struct perf_stat_config *config,
>  }
>
>  static void print_metric_headers_json(struct perf_stat_config *config,
> -                                     const char *prefix __maybe_unused,
>                                       bool no_indent __maybe_unused)
>  {
>         if (config->interval)
> @@ -1032,8 +1027,7 @@ static void print_metric_headers_json(struct perf_stat_config *config,
>  }
>
>  static void print_metric_headers(struct perf_stat_config *config,
> -                                struct evlist *evlist,
> -                                const char *prefix, bool no_indent)
> +                                struct evlist *evlist, bool no_indent)
>  {
>         struct evsel *counter;
>         struct outstate os = {
> @@ -1047,11 +1041,11 @@ static void print_metric_headers(struct perf_stat_config *config,
>         };
>
>         if (config->json_output)
> -               print_metric_headers_json(config, prefix, no_indent);
> +               print_metric_headers_json(config, no_indent);
>         else if (config->csv_output)
> -               print_metric_headers_csv(config, prefix, no_indent);
> +               print_metric_headers_csv(config, no_indent);
>         else
> -               print_metric_headers_std(config, prefix, no_indent);
> +               print_metric_headers_std(config, no_indent);
>
>         if (config->iostat_run)
>                 iostat_print_header_prefix(config);
> @@ -1132,7 +1126,7 @@ static void print_header_interval_std(struct perf_stat_config *config,
>         }
>
>         if (config->metric_only)
> -               print_metric_headers(config, evlist, " ", true);
> +               print_metric_headers(config, evlist, true);
>         else
>                 fprintf(output, " %*s %*s events\n",
>                         COUNTS_LEN, "counts", config->unit_width, "unit");
> @@ -1168,7 +1162,7 @@ static void print_header_std(struct perf_stat_config *config,
>         fprintf(output, ":\n\n");
>
>         if (config->metric_only)
> -               print_metric_headers(config, evlist, " ", false);
> +               print_metric_headers(config, evlist, false);
>  }
>
>  static void print_header_csv(struct perf_stat_config *config,
> @@ -1178,7 +1172,7 @@ static void print_header_csv(struct perf_stat_config *config,
>                              const char **argv __maybe_unused)
>  {
>         if (config->metric_only)
> -               print_metric_headers(config, evlist, " ", true);
> +               print_metric_headers(config, evlist, true);
>  }
>  static void print_header_json(struct perf_stat_config *config,
>                               struct target *_target __maybe_unused,
> @@ -1187,7 +1181,7 @@ static void print_header_json(struct perf_stat_config *config,
>                               const char **argv __maybe_unused)
>  {
>         if (config->metric_only)
> -               print_metric_headers(config, evlist, " ", true);
> +               print_metric_headers(config, evlist, true);
>  }
>
>  static void print_header(struct perf_stat_config *config,
> --
> 2.38.1.584.g0f3c55d4c2-goog
>
  
Ian Rogers Nov. 30, 2022, 5:09 a.m. UTC | #2
On Wed, Nov 23, 2022 at 3:23 PM Ian Rogers <irogers@google.com> wrote:
>
> On Wed, Nov 23, 2022 at 10:02 AM Namhyung Kim <namhyung@kernel.org> wrote:
> >
> > It always passes a whitespace to the function, thus we can just add it to the
> > function body.  Furthermore, it's only used in the normal output mode.
> >
> > Well, actually CSV used it but it doesn't need to since we don't care about the
> > indentation or alignment in the CSV output.
> >
> > Signed-off-by: Namhyung Kim <namhyung@kernel.org>
>
> Acked-by: Ian Rogers <irogers@google.com>
>
> Thanks,
> Ian

I suspect this may be responsible for a metric segv that I'm now
seeing in Arnaldo's tree:

$ gdb --args perf stat -M Backend true
...
Performance counter stats for 'true':

        4,712,355      TOPDOWN.SLOTS                    #     17.3 %
tma_core_bound

Program received signal SIGSEGV, Segmentation fault.
__strlen_evex () at ../sysdeps/x86_64/multiarch/strlen-evex.S:77
77      ../sysdeps/x86_64/multiarch/strlen-evex.S: No such file or directory.
(gdb) bt
#0  __strlen_evex () at ../sysdeps/x86_64/multiarch/strlen-evex.S:77
#1  0x00007ffff74749a5 in __GI__IO_fputs (str=0x0, fp=0x7ffff75f5680
<_IO_2_1_stderr_>)
   at ./libio/iofputs.c:33
#2  0x0000555555779f28 in do_new_line_std (config=0x555555e077c0
<stat_config>, os=0x7fffffffbf10)
   at util/stat-display.c:356
#3  0x000055555577a081 in print_metric_std (config=0x555555e077c0
<stat_config>,
   ctx=0x7fffffffbf10, color=0x0, fmt=0x5555558b77b5 "%8.1f",
   unit=0x7fffffffbb10 "%  tma_memory_bound", val=13.165355724442199)
at util/stat-display.c:380
#4  0x00005555557768b6 in generic_metric (config=0x555555e077c0 <stat_config>,
   metric_expr=0x55555593d5b7 "((CYCLE_ACTIVITY.STALLS_MEM_ANY +
EXE_ACTIVITY.BOUND_ON_STORES) / (C
YCLE_ACTIVITY.STALLS_TOTAL + (EXE_ACTIVITY.1_PORTS_UTIL + tma_retiring
* EXE_ACTIVITY.2_PORTS_UTIL)
+ EXE_ACTIVITY.BOUND_ON_STORES))"..., metric_events=0x555555f334e0,
metric_refs=0x555555ec81d0,
   name=0x555555f32e80 "TOPDOWN.SLOTS", metric_name=0x555555f26c80
"tma_memory_bound",
   metric_unit=0x55555593d5b1 "100%", runtime=0, map_idx=0,
out=0x7fffffffbd90,
   st=0x555555e9e620 <rt_stat>) at util/stat-shadow.c:934
#5  0x0000555555778cac in perf_stat__print_shadow_stats
(config=0x555555e077c0 <stat_config>,
   evsel=0x555555f289d0, avg=4712355, map_idx=0, out=0x7fffffffbd90,
   metric_events=0x555555e078e8 <stat_config+296>, st=0x555555e9e620 <rt_stat>)
   at util/stat-shadow.c:1329
#6  0x000055555577b6a0 in printout (config=0x555555e077c0
<stat_config>, os=0x7fffffffbf10,
   uval=4712355, run=325322, ena=325322, noise=4712355, map_idx=0) at
util/stat-display.c:741
#7  0x000055555577bc74 in print_counter_aggrdata
(config=0x555555e077c0 <stat_config>,
   counter=0x555555f289d0, s=0, os=0x7fffffffbf10) at util/stat-display.c:838
#8  0x000055555577c1d8 in print_counter (config=0x555555e077c0 <stat_config>,
   counter=0x555555f289d0, os=0x7fffffffbf10) at util/stat-display.c:957
#9  0x000055555577dba0 in evlist__print_counters (evlist=0x555555ec3610,
   config=0x555555e077c0 <stat_config>, _target=0x555555e01c80
<target>, ts=0x0, argc=1,
   argv=0x7fffffffe450) at util/stat-display.c:1413
#10 0x00005555555fc821 in print_counters (ts=0x0, argc=1, argv=0x7fffffffe450)
   at builtin-stat.c:1040
#11 0x000055555560091a in cmd_stat (argc=1, argv=0x7fffffffe450) at
builtin-stat.c:2665
#12 0x00005555556b1eea in run_builtin (p=0x555555e11f70
<commands+336>, argc=4,
   argv=0x7fffffffe450) at perf.c:322
#13 0x00005555556b2181 in handle_internal_command (argc=4,
argv=0x7fffffffe450) at perf.c:376
#14 0x00005555556b22d7 in run_argv (argcp=0x7fffffffe27c,
argv=0x7fffffffe270) at perf.c:420
#15 0x00005555556b26ef in main (argc=4, argv=0x7fffffffe450) at perf.c:550
(gdb)

Thanks,
Ian

> > ---
> >  tools/perf/util/stat-display.c | 26 ++++++++++----------------
> >  1 file changed, 10 insertions(+), 16 deletions(-)
> >
> > diff --git a/tools/perf/util/stat-display.c b/tools/perf/util/stat-display.c
> > index 744b7a40f59a..deed6ccf072f 100644
> > --- a/tools/perf/util/stat-display.c
> > +++ b/tools/perf/util/stat-display.c
> > @@ -996,10 +996,9 @@ static void print_no_aggr_metric(struct perf_stat_config *config,
> >  }
> >
> >  static void print_metric_headers_std(struct perf_stat_config *config,
> > -                                    const char *prefix, bool no_indent)
> > +                                    bool no_indent)
> >  {
> > -       if (prefix)
> > -               fprintf(config->output, "%s", prefix);
> > +       fputc(' ', config->output);
> >
> >         if (!no_indent) {
> >                 int len = aggr_header_lens[config->aggr_mode];
> > @@ -1012,11 +1011,8 @@ static void print_metric_headers_std(struct perf_stat_config *config,
> >  }
> >
> >  static void print_metric_headers_csv(struct perf_stat_config *config,
> > -                                    const char *prefix,
> >                                      bool no_indent __maybe_unused)
> >  {
> > -       if (prefix)
> > -               fprintf(config->output, "%s", prefix);
> >         if (config->interval)
> >                 fputs("time,", config->output);
> >         if (!config->iostat_run)
> > @@ -1024,7 +1020,6 @@ static void print_metric_headers_csv(struct perf_stat_config *config,
> >  }
> >
> >  static void print_metric_headers_json(struct perf_stat_config *config,
> > -                                     const char *prefix __maybe_unused,
> >                                       bool no_indent __maybe_unused)
> >  {
> >         if (config->interval)
> > @@ -1032,8 +1027,7 @@ static void print_metric_headers_json(struct perf_stat_config *config,
> >  }
> >
> >  static void print_metric_headers(struct perf_stat_config *config,
> > -                                struct evlist *evlist,
> > -                                const char *prefix, bool no_indent)
> > +                                struct evlist *evlist, bool no_indent)
> >  {
> >         struct evsel *counter;
> >         struct outstate os = {
> > @@ -1047,11 +1041,11 @@ static void print_metric_headers(struct perf_stat_config *config,
> >         };
> >
> >         if (config->json_output)
> > -               print_metric_headers_json(config, prefix, no_indent);
> > +               print_metric_headers_json(config, no_indent);
> >         else if (config->csv_output)
> > -               print_metric_headers_csv(config, prefix, no_indent);
> > +               print_metric_headers_csv(config, no_indent);
> >         else
> > -               print_metric_headers_std(config, prefix, no_indent);
> > +               print_metric_headers_std(config, no_indent);
> >
> >         if (config->iostat_run)
> >                 iostat_print_header_prefix(config);
> > @@ -1132,7 +1126,7 @@ static void print_header_interval_std(struct perf_stat_config *config,
> >         }
> >
> >         if (config->metric_only)
> > -               print_metric_headers(config, evlist, " ", true);
> > +               print_metric_headers(config, evlist, true);
> >         else
> >                 fprintf(output, " %*s %*s events\n",
> >                         COUNTS_LEN, "counts", config->unit_width, "unit");
> > @@ -1168,7 +1162,7 @@ static void print_header_std(struct perf_stat_config *config,
> >         fprintf(output, ":\n\n");
> >
> >         if (config->metric_only)
> > -               print_metric_headers(config, evlist, " ", false);
> > +               print_metric_headers(config, evlist, false);
> >  }
> >
> >  static void print_header_csv(struct perf_stat_config *config,
> > @@ -1178,7 +1172,7 @@ static void print_header_csv(struct perf_stat_config *config,
> >                              const char **argv __maybe_unused)
> >  {
> >         if (config->metric_only)
> > -               print_metric_headers(config, evlist, " ", true);
> > +               print_metric_headers(config, evlist, true);
> >  }
> >  static void print_header_json(struct perf_stat_config *config,
> >                               struct target *_target __maybe_unused,
> > @@ -1187,7 +1181,7 @@ static void print_header_json(struct perf_stat_config *config,
> >                               const char **argv __maybe_unused)
> >  {
> >         if (config->metric_only)
> > -               print_metric_headers(config, evlist, " ", true);
> > +               print_metric_headers(config, evlist, true);
> >  }
> >
> >  static void print_header(struct perf_stat_config *config,
> > --
> > 2.38.1.584.g0f3c55d4c2-goog
> >
  
Ian Rogers Nov. 30, 2022, 5:13 a.m. UTC | #3
On Tue, Nov 29, 2022 at 9:09 PM Ian Rogers <irogers@google.com> wrote:
>
> On Wed, Nov 23, 2022 at 3:23 PM Ian Rogers <irogers@google.com> wrote:
> >
> > On Wed, Nov 23, 2022 at 10:02 AM Namhyung Kim <namhyung@kernel.org> wrote:
> > >
> > > It always passes a whitespace to the function, thus we can just add it to the
> > > function body.  Furthermore, it's only used in the normal output mode.
> > >
> > > Well, actually CSV used it but it doesn't need to since we don't care about the
> > > indentation or alignment in the CSV output.
> > >
> > > Signed-off-by: Namhyung Kim <namhyung@kernel.org>
> >
> > Acked-by: Ian Rogers <irogers@google.com>
> >
> > Thanks,
> > Ian
>
> I suspect this may be responsible for a metric segv that I'm now
> seeing in Arnaldo's tree:
>
> $ gdb --args perf stat -M Backend true
> ...
> Performance counter stats for 'true':
>
>         4,712,355      TOPDOWN.SLOTS                    #     17.3 %
> tma_core_bound
>
> Program received signal SIGSEGV, Segmentation fault.
> __strlen_evex () at ../sysdeps/x86_64/multiarch/strlen-evex.S:77
> 77      ../sysdeps/x86_64/multiarch/strlen-evex.S: No such file or directory.
> (gdb) bt
> #0  __strlen_evex () at ../sysdeps/x86_64/multiarch/strlen-evex.S:77
> #1  0x00007ffff74749a5 in __GI__IO_fputs (str=0x0, fp=0x7ffff75f5680
> <_IO_2_1_stderr_>)
>    at ./libio/iofputs.c:33
> #2  0x0000555555779f28 in do_new_line_std (config=0x555555e077c0
> <stat_config>, os=0x7fffffffbf10)
>    at util/stat-display.c:356
> #3  0x000055555577a081 in print_metric_std (config=0x555555e077c0
> <stat_config>,
>    ctx=0x7fffffffbf10, color=0x0, fmt=0x5555558b77b5 "%8.1f",
>    unit=0x7fffffffbb10 "%  tma_memory_bound", val=13.165355724442199)
> at util/stat-display.c:380
> #4  0x00005555557768b6 in generic_metric (config=0x555555e077c0 <stat_config>,
>    metric_expr=0x55555593d5b7 "((CYCLE_ACTIVITY.STALLS_MEM_ANY +
> EXE_ACTIVITY.BOUND_ON_STORES) / (C
> YCLE_ACTIVITY.STALLS_TOTAL + (EXE_ACTIVITY.1_PORTS_UTIL + tma_retiring
> * EXE_ACTIVITY.2_PORTS_UTIL)
> + EXE_ACTIVITY.BOUND_ON_STORES))"..., metric_events=0x555555f334e0,
> metric_refs=0x555555ec81d0,
>    name=0x555555f32e80 "TOPDOWN.SLOTS", metric_name=0x555555f26c80
> "tma_memory_bound",
>    metric_unit=0x55555593d5b1 "100%", runtime=0, map_idx=0,
> out=0x7fffffffbd90,
>    st=0x555555e9e620 <rt_stat>) at util/stat-shadow.c:934
> #5  0x0000555555778cac in perf_stat__print_shadow_stats
> (config=0x555555e077c0 <stat_config>,
>    evsel=0x555555f289d0, avg=4712355, map_idx=0, out=0x7fffffffbd90,
>    metric_events=0x555555e078e8 <stat_config+296>, st=0x555555e9e620 <rt_stat>)
>    at util/stat-shadow.c:1329
> #6  0x000055555577b6a0 in printout (config=0x555555e077c0
> <stat_config>, os=0x7fffffffbf10,
>    uval=4712355, run=325322, ena=325322, noise=4712355, map_idx=0) at
> util/stat-display.c:741
> #7  0x000055555577bc74 in print_counter_aggrdata
> (config=0x555555e077c0 <stat_config>,
>    counter=0x555555f289d0, s=0, os=0x7fffffffbf10) at util/stat-display.c:838
> #8  0x000055555577c1d8 in print_counter (config=0x555555e077c0 <stat_config>,
>    counter=0x555555f289d0, os=0x7fffffffbf10) at util/stat-display.c:957
> #9  0x000055555577dba0 in evlist__print_counters (evlist=0x555555ec3610,
>    config=0x555555e077c0 <stat_config>, _target=0x555555e01c80
> <target>, ts=0x0, argc=1,
>    argv=0x7fffffffe450) at util/stat-display.c:1413
> #10 0x00005555555fc821 in print_counters (ts=0x0, argc=1, argv=0x7fffffffe450)
>    at builtin-stat.c:1040
> #11 0x000055555560091a in cmd_stat (argc=1, argv=0x7fffffffe450) at
> builtin-stat.c:2665
> #12 0x00005555556b1eea in run_builtin (p=0x555555e11f70
> <commands+336>, argc=4,
>    argv=0x7fffffffe450) at perf.c:322
> #13 0x00005555556b2181 in handle_internal_command (argc=4,
> argv=0x7fffffffe450) at perf.c:376
> #14 0x00005555556b22d7 in run_argv (argcp=0x7fffffffe27c,
> argv=0x7fffffffe270) at perf.c:420
> #15 0x00005555556b26ef in main (argc=4, argv=0x7fffffffe450) at perf.c:550
> (gdb)
>
> Thanks,
> Ian

More specifically, I think os->prefix needs testing for NULL:
https://git.kernel.org/pub/scm/linux/kernel/git/acme/linux.git/tree/tools/perf/util/stat-display.c?h=perf/core#n356
so:
fputs(os->prefix, os->fh);
should be:
if (os->prefix)
  fputs(os->prefix, os->fh);

Thanks,
Ian

> > > ---
> > >  tools/perf/util/stat-display.c | 26 ++++++++++----------------
> > >  1 file changed, 10 insertions(+), 16 deletions(-)
> > >
> > > diff --git a/tools/perf/util/stat-display.c b/tools/perf/util/stat-display.c
> > > index 744b7a40f59a..deed6ccf072f 100644
> > > --- a/tools/perf/util/stat-display.c
> > > +++ b/tools/perf/util/stat-display.c
> > > @@ -996,10 +996,9 @@ static void print_no_aggr_metric(struct perf_stat_config *config,
> > >  }
> > >
> > >  static void print_metric_headers_std(struct perf_stat_config *config,
> > > -                                    const char *prefix, bool no_indent)
> > > +                                    bool no_indent)
> > >  {
> > > -       if (prefix)
> > > -               fprintf(config->output, "%s", prefix);
> > > +       fputc(' ', config->output);
> > >
> > >         if (!no_indent) {
> > >                 int len = aggr_header_lens[config->aggr_mode];
> > > @@ -1012,11 +1011,8 @@ static void print_metric_headers_std(struct perf_stat_config *config,
> > >  }
> > >
> > >  static void print_metric_headers_csv(struct perf_stat_config *config,
> > > -                                    const char *prefix,
> > >                                      bool no_indent __maybe_unused)
> > >  {
> > > -       if (prefix)
> > > -               fprintf(config->output, "%s", prefix);
> > >         if (config->interval)
> > >                 fputs("time,", config->output);
> > >         if (!config->iostat_run)
> > > @@ -1024,7 +1020,6 @@ static void print_metric_headers_csv(struct perf_stat_config *config,
> > >  }
> > >
> > >  static void print_metric_headers_json(struct perf_stat_config *config,
> > > -                                     const char *prefix __maybe_unused,
> > >                                       bool no_indent __maybe_unused)
> > >  {
> > >         if (config->interval)
> > > @@ -1032,8 +1027,7 @@ static void print_metric_headers_json(struct perf_stat_config *config,
> > >  }
> > >
> > >  static void print_metric_headers(struct perf_stat_config *config,
> > > -                                struct evlist *evlist,
> > > -                                const char *prefix, bool no_indent)
> > > +                                struct evlist *evlist, bool no_indent)
> > >  {
> > >         struct evsel *counter;
> > >         struct outstate os = {
> > > @@ -1047,11 +1041,11 @@ static void print_metric_headers(struct perf_stat_config *config,
> > >         };
> > >
> > >         if (config->json_output)
> > > -               print_metric_headers_json(config, prefix, no_indent);
> > > +               print_metric_headers_json(config, no_indent);
> > >         else if (config->csv_output)
> > > -               print_metric_headers_csv(config, prefix, no_indent);
> > > +               print_metric_headers_csv(config, no_indent);
> > >         else
> > > -               print_metric_headers_std(config, prefix, no_indent);
> > > +               print_metric_headers_std(config, no_indent);
> > >
> > >         if (config->iostat_run)
> > >                 iostat_print_header_prefix(config);
> > > @@ -1132,7 +1126,7 @@ static void print_header_interval_std(struct perf_stat_config *config,
> > >         }
> > >
> > >         if (config->metric_only)
> > > -               print_metric_headers(config, evlist, " ", true);
> > > +               print_metric_headers(config, evlist, true);
> > >         else
> > >                 fprintf(output, " %*s %*s events\n",
> > >                         COUNTS_LEN, "counts", config->unit_width, "unit");
> > > @@ -1168,7 +1162,7 @@ static void print_header_std(struct perf_stat_config *config,
> > >         fprintf(output, ":\n\n");
> > >
> > >         if (config->metric_only)
> > > -               print_metric_headers(config, evlist, " ", false);
> > > +               print_metric_headers(config, evlist, false);
> > >  }
> > >
> > >  static void print_header_csv(struct perf_stat_config *config,
> > > @@ -1178,7 +1172,7 @@ static void print_header_csv(struct perf_stat_config *config,
> > >                              const char **argv __maybe_unused)
> > >  {
> > >         if (config->metric_only)
> > > -               print_metric_headers(config, evlist, " ", true);
> > > +               print_metric_headers(config, evlist, true);
> > >  }
> > >  static void print_header_json(struct perf_stat_config *config,
> > >                               struct target *_target __maybe_unused,
> > > @@ -1187,7 +1181,7 @@ static void print_header_json(struct perf_stat_config *config,
> > >                               const char **argv __maybe_unused)
> > >  {
> > >         if (config->metric_only)
> > > -               print_metric_headers(config, evlist, " ", true);
> > > +               print_metric_headers(config, evlist, true);
> > >  }
> > >
> > >  static void print_header(struct perf_stat_config *config,
> > > --
> > > 2.38.1.584.g0f3c55d4c2-goog
> > >
  
Namhyung Kim Nov. 30, 2022, 9:21 p.m. UTC | #4
On Tue, Nov 29, 2022 at 9:13 PM Ian Rogers <irogers@google.com> wrote:
>
> On Tue, Nov 29, 2022 at 9:09 PM Ian Rogers <irogers@google.com> wrote:
> >
> > On Wed, Nov 23, 2022 at 3:23 PM Ian Rogers <irogers@google.com> wrote:
> > >
> > > On Wed, Nov 23, 2022 at 10:02 AM Namhyung Kim <namhyung@kernel.org> wrote:
> > > >
> > > > It always passes a whitespace to the function, thus we can just add it to the
> > > > function body.  Furthermore, it's only used in the normal output mode.
> > > >
> > > > Well, actually CSV used it but it doesn't need to since we don't care about the
> > > > indentation or alignment in the CSV output.
> > > >
> > > > Signed-off-by: Namhyung Kim <namhyung@kernel.org>
> > >
> > > Acked-by: Ian Rogers <irogers@google.com>
> > >
> > > Thanks,
> > > Ian
> >
> > I suspect this may be responsible for a metric segv that I'm now
> > seeing in Arnaldo's tree:
> >
> > $ gdb --args perf stat -M Backend true
> > ...
> > Performance counter stats for 'true':
> >
> >         4,712,355      TOPDOWN.SLOTS                    #     17.3 %
> > tma_core_bound
> >
> > Program received signal SIGSEGV, Segmentation fault.
> > __strlen_evex () at ../sysdeps/x86_64/multiarch/strlen-evex.S:77
> > 77      ../sysdeps/x86_64/multiarch/strlen-evex.S: No such file or directory.
> > (gdb) bt
> > #0  __strlen_evex () at ../sysdeps/x86_64/multiarch/strlen-evex.S:77
> > #1  0x00007ffff74749a5 in __GI__IO_fputs (str=0x0, fp=0x7ffff75f5680
> > <_IO_2_1_stderr_>)
> >    at ./libio/iofputs.c:33
> > #2  0x0000555555779f28 in do_new_line_std (config=0x555555e077c0
> > <stat_config>, os=0x7fffffffbf10)
> >    at util/stat-display.c:356
> > #3  0x000055555577a081 in print_metric_std (config=0x555555e077c0
> > <stat_config>,
> >    ctx=0x7fffffffbf10, color=0x0, fmt=0x5555558b77b5 "%8.1f",
> >    unit=0x7fffffffbb10 "%  tma_memory_bound", val=13.165355724442199)
> > at util/stat-display.c:380
> > #4  0x00005555557768b6 in generic_metric (config=0x555555e077c0 <stat_config>,
> >    metric_expr=0x55555593d5b7 "((CYCLE_ACTIVITY.STALLS_MEM_ANY +
> > EXE_ACTIVITY.BOUND_ON_STORES) / (C
> > YCLE_ACTIVITY.STALLS_TOTAL + (EXE_ACTIVITY.1_PORTS_UTIL + tma_retiring
> > * EXE_ACTIVITY.2_PORTS_UTIL)
> > + EXE_ACTIVITY.BOUND_ON_STORES))"..., metric_events=0x555555f334e0,
> > metric_refs=0x555555ec81d0,
> >    name=0x555555f32e80 "TOPDOWN.SLOTS", metric_name=0x555555f26c80
> > "tma_memory_bound",
> >    metric_unit=0x55555593d5b1 "100%", runtime=0, map_idx=0,
> > out=0x7fffffffbd90,
> >    st=0x555555e9e620 <rt_stat>) at util/stat-shadow.c:934
> > #5  0x0000555555778cac in perf_stat__print_shadow_stats
> > (config=0x555555e077c0 <stat_config>,
> >    evsel=0x555555f289d0, avg=4712355, map_idx=0, out=0x7fffffffbd90,
> >    metric_events=0x555555e078e8 <stat_config+296>, st=0x555555e9e620 <rt_stat>)
> >    at util/stat-shadow.c:1329
> > #6  0x000055555577b6a0 in printout (config=0x555555e077c0
> > <stat_config>, os=0x7fffffffbf10,
> >    uval=4712355, run=325322, ena=325322, noise=4712355, map_idx=0) at
> > util/stat-display.c:741
> > #7  0x000055555577bc74 in print_counter_aggrdata
> > (config=0x555555e077c0 <stat_config>,
> >    counter=0x555555f289d0, s=0, os=0x7fffffffbf10) at util/stat-display.c:838
> > #8  0x000055555577c1d8 in print_counter (config=0x555555e077c0 <stat_config>,
> >    counter=0x555555f289d0, os=0x7fffffffbf10) at util/stat-display.c:957
> > #9  0x000055555577dba0 in evlist__print_counters (evlist=0x555555ec3610,
> >    config=0x555555e077c0 <stat_config>, _target=0x555555e01c80
> > <target>, ts=0x0, argc=1,
> >    argv=0x7fffffffe450) at util/stat-display.c:1413
> > #10 0x00005555555fc821 in print_counters (ts=0x0, argc=1, argv=0x7fffffffe450)
> >    at builtin-stat.c:1040
> > #11 0x000055555560091a in cmd_stat (argc=1, argv=0x7fffffffe450) at
> > builtin-stat.c:2665
> > #12 0x00005555556b1eea in run_builtin (p=0x555555e11f70
> > <commands+336>, argc=4,
> >    argv=0x7fffffffe450) at perf.c:322
> > #13 0x00005555556b2181 in handle_internal_command (argc=4,
> > argv=0x7fffffffe450) at perf.c:376
> > #14 0x00005555556b22d7 in run_argv (argcp=0x7fffffffe27c,
> > argv=0x7fffffffe270) at perf.c:420
> > #15 0x00005555556b26ef in main (argc=4, argv=0x7fffffffe450) at perf.c:550
> > (gdb)
> >
> > Thanks,
> > Ian
>
> More specifically, I think os->prefix needs testing for NULL:
> https://git.kernel.org/pub/scm/linux/kernel/git/acme/linux.git/tree/tools/perf/util/stat-display.c?h=perf/core#n356
> so:
> fputs(os->prefix, os->fh);
> should be:
> if (os->prefix)
>   fputs(os->prefix, os->fh);

Yep, could you please send it as a formal patch?

Thanks,
Namhyung
  
Arnaldo Carvalho de Melo Dec. 5, 2022, 12:22 p.m. UTC | #5
Em Tue, Nov 29, 2022 at 09:13:11PM -0800, Ian Rogers escreveu:
> On Tue, Nov 29, 2022 at 9:09 PM Ian Rogers <irogers@google.com> wrote:
> >
> > On Wed, Nov 23, 2022 at 3:23 PM Ian Rogers <irogers@google.com> wrote:
> > >
> > > On Wed, Nov 23, 2022 at 10:02 AM Namhyung Kim <namhyung@kernel.org> wrote:
> > > >
> > > > It always passes a whitespace to the function, thus we can just add it to the
> > > > function body.  Furthermore, it's only used in the normal output mode.
> > > >
> > > > Well, actually CSV used it but it doesn't need to since we don't care about the
> > > > indentation or alignment in the CSV output.
> > > >
> > > > Signed-off-by: Namhyung Kim <namhyung@kernel.org>
> > >
> > > Acked-by: Ian Rogers <irogers@google.com>
> > >
> > > Thanks,
> > > Ian
> >
> > I suspect this may be responsible for a metric segv that I'm now
> > seeing in Arnaldo's tree:
> >
> > $ gdb --args perf stat -M Backend true
> > ...
> > Performance counter stats for 'true':
> >
> >         4,712,355      TOPDOWN.SLOTS                    #     17.3 %
> > tma_core_bound
> >
> > Program received signal SIGSEGV, Segmentation fault.
> > __strlen_evex () at ../sysdeps/x86_64/multiarch/strlen-evex.S:77
> > 77      ../sysdeps/x86_64/multiarch/strlen-evex.S: No such file or directory.
> > (gdb) bt
> > #0  __strlen_evex () at ../sysdeps/x86_64/multiarch/strlen-evex.S:77
> > #1  0x00007ffff74749a5 in __GI__IO_fputs (str=0x0, fp=0x7ffff75f5680
> > <_IO_2_1_stderr_>)
> >    at ./libio/iofputs.c:33
> > #2  0x0000555555779f28 in do_new_line_std (config=0x555555e077c0
> > <stat_config>, os=0x7fffffffbf10)
> >    at util/stat-display.c:356
> > #3  0x000055555577a081 in print_metric_std (config=0x555555e077c0
> > <stat_config>,
> >    ctx=0x7fffffffbf10, color=0x0, fmt=0x5555558b77b5 "%8.1f",
> >    unit=0x7fffffffbb10 "%  tma_memory_bound", val=13.165355724442199)
> > at util/stat-display.c:380
> > #4  0x00005555557768b6 in generic_metric (config=0x555555e077c0 <stat_config>,
> >    metric_expr=0x55555593d5b7 "((CYCLE_ACTIVITY.STALLS_MEM_ANY +
> > EXE_ACTIVITY.BOUND_ON_STORES) / (C
> > YCLE_ACTIVITY.STALLS_TOTAL + (EXE_ACTIVITY.1_PORTS_UTIL + tma_retiring
> > * EXE_ACTIVITY.2_PORTS_UTIL)
> > + EXE_ACTIVITY.BOUND_ON_STORES))"..., metric_events=0x555555f334e0,
> > metric_refs=0x555555ec81d0,
> >    name=0x555555f32e80 "TOPDOWN.SLOTS", metric_name=0x555555f26c80
> > "tma_memory_bound",
> >    metric_unit=0x55555593d5b1 "100%", runtime=0, map_idx=0,
> > out=0x7fffffffbd90,
> >    st=0x555555e9e620 <rt_stat>) at util/stat-shadow.c:934
> > #5  0x0000555555778cac in perf_stat__print_shadow_stats
> > (config=0x555555e077c0 <stat_config>,
> >    evsel=0x555555f289d0, avg=4712355, map_idx=0, out=0x7fffffffbd90,
> >    metric_events=0x555555e078e8 <stat_config+296>, st=0x555555e9e620 <rt_stat>)
> >    at util/stat-shadow.c:1329
> > #6  0x000055555577b6a0 in printout (config=0x555555e077c0
> > <stat_config>, os=0x7fffffffbf10,
> >    uval=4712355, run=325322, ena=325322, noise=4712355, map_idx=0) at
> > util/stat-display.c:741
> > #7  0x000055555577bc74 in print_counter_aggrdata
> > (config=0x555555e077c0 <stat_config>,
> >    counter=0x555555f289d0, s=0, os=0x7fffffffbf10) at util/stat-display.c:838
> > #8  0x000055555577c1d8 in print_counter (config=0x555555e077c0 <stat_config>,
> >    counter=0x555555f289d0, os=0x7fffffffbf10) at util/stat-display.c:957
> > #9  0x000055555577dba0 in evlist__print_counters (evlist=0x555555ec3610,
> >    config=0x555555e077c0 <stat_config>, _target=0x555555e01c80
> > <target>, ts=0x0, argc=1,
> >    argv=0x7fffffffe450) at util/stat-display.c:1413
> > #10 0x00005555555fc821 in print_counters (ts=0x0, argc=1, argv=0x7fffffffe450)
> >    at builtin-stat.c:1040
> > #11 0x000055555560091a in cmd_stat (argc=1, argv=0x7fffffffe450) at
> > builtin-stat.c:2665
> > #12 0x00005555556b1eea in run_builtin (p=0x555555e11f70
> > <commands+336>, argc=4,
> >    argv=0x7fffffffe450) at perf.c:322
> > #13 0x00005555556b2181 in handle_internal_command (argc=4,
> > argv=0x7fffffffe450) at perf.c:376
> > #14 0x00005555556b22d7 in run_argv (argcp=0x7fffffffe27c,
> > argv=0x7fffffffe270) at perf.c:420
> > #15 0x00005555556b26ef in main (argc=4, argv=0x7fffffffe450) at perf.c:550
> > (gdb)
> >
> > Thanks,
> > Ian
> 
> More specifically, I think os->prefix needs testing for NULL:
> https://git.kernel.org/pub/scm/linux/kernel/git/acme/linux.git/tree/tools/perf/util/stat-display.c?h=perf/core#n356
> so:
> fputs(os->prefix, os->fh);
> should be:
> if (os->prefix)
>   fputs(os->prefix, os->fh);

Going thru the messages, for now I just added the test.

- Arnaldo
 
> Thanks,
> Ian
> 
> > > > ---
> > > >  tools/perf/util/stat-display.c | 26 ++++++++++----------------
> > > >  1 file changed, 10 insertions(+), 16 deletions(-)
> > > >
> > > > diff --git a/tools/perf/util/stat-display.c b/tools/perf/util/stat-display.c
> > > > index 744b7a40f59a..deed6ccf072f 100644
> > > > --- a/tools/perf/util/stat-display.c
> > > > +++ b/tools/perf/util/stat-display.c
> > > > @@ -996,10 +996,9 @@ static void print_no_aggr_metric(struct perf_stat_config *config,
> > > >  }
> > > >
> > > >  static void print_metric_headers_std(struct perf_stat_config *config,
> > > > -                                    const char *prefix, bool no_indent)
> > > > +                                    bool no_indent)
> > > >  {
> > > > -       if (prefix)
> > > > -               fprintf(config->output, "%s", prefix);
> > > > +       fputc(' ', config->output);
> > > >
> > > >         if (!no_indent) {
> > > >                 int len = aggr_header_lens[config->aggr_mode];
> > > > @@ -1012,11 +1011,8 @@ static void print_metric_headers_std(struct perf_stat_config *config,
> > > >  }
> > > >
> > > >  static void print_metric_headers_csv(struct perf_stat_config *config,
> > > > -                                    const char *prefix,
> > > >                                      bool no_indent __maybe_unused)
> > > >  {
> > > > -       if (prefix)
> > > > -               fprintf(config->output, "%s", prefix);
> > > >         if (config->interval)
> > > >                 fputs("time,", config->output);
> > > >         if (!config->iostat_run)
> > > > @@ -1024,7 +1020,6 @@ static void print_metric_headers_csv(struct perf_stat_config *config,
> > > >  }
> > > >
> > > >  static void print_metric_headers_json(struct perf_stat_config *config,
> > > > -                                     const char *prefix __maybe_unused,
> > > >                                       bool no_indent __maybe_unused)
> > > >  {
> > > >         if (config->interval)
> > > > @@ -1032,8 +1027,7 @@ static void print_metric_headers_json(struct perf_stat_config *config,
> > > >  }
> > > >
> > > >  static void print_metric_headers(struct perf_stat_config *config,
> > > > -                                struct evlist *evlist,
> > > > -                                const char *prefix, bool no_indent)
> > > > +                                struct evlist *evlist, bool no_indent)
> > > >  {
> > > >         struct evsel *counter;
> > > >         struct outstate os = {
> > > > @@ -1047,11 +1041,11 @@ static void print_metric_headers(struct perf_stat_config *config,
> > > >         };
> > > >
> > > >         if (config->json_output)
> > > > -               print_metric_headers_json(config, prefix, no_indent);
> > > > +               print_metric_headers_json(config, no_indent);
> > > >         else if (config->csv_output)
> > > > -               print_metric_headers_csv(config, prefix, no_indent);
> > > > +               print_metric_headers_csv(config, no_indent);
> > > >         else
> > > > -               print_metric_headers_std(config, prefix, no_indent);
> > > > +               print_metric_headers_std(config, no_indent);
> > > >
> > > >         if (config->iostat_run)
> > > >                 iostat_print_header_prefix(config);
> > > > @@ -1132,7 +1126,7 @@ static void print_header_interval_std(struct perf_stat_config *config,
> > > >         }
> > > >
> > > >         if (config->metric_only)
> > > > -               print_metric_headers(config, evlist, " ", true);
> > > > +               print_metric_headers(config, evlist, true);
> > > >         else
> > > >                 fprintf(output, " %*s %*s events\n",
> > > >                         COUNTS_LEN, "counts", config->unit_width, "unit");
> > > > @@ -1168,7 +1162,7 @@ static void print_header_std(struct perf_stat_config *config,
> > > >         fprintf(output, ":\n\n");
> > > >
> > > >         if (config->metric_only)
> > > > -               print_metric_headers(config, evlist, " ", false);
> > > > +               print_metric_headers(config, evlist, false);
> > > >  }
> > > >
> > > >  static void print_header_csv(struct perf_stat_config *config,
> > > > @@ -1178,7 +1172,7 @@ static void print_header_csv(struct perf_stat_config *config,
> > > >                              const char **argv __maybe_unused)
> > > >  {
> > > >         if (config->metric_only)
> > > > -               print_metric_headers(config, evlist, " ", true);
> > > > +               print_metric_headers(config, evlist, true);
> > > >  }
> > > >  static void print_header_json(struct perf_stat_config *config,
> > > >                               struct target *_target __maybe_unused,
> > > > @@ -1187,7 +1181,7 @@ static void print_header_json(struct perf_stat_config *config,
> > > >                               const char **argv __maybe_unused)
> > > >  {
> > > >         if (config->metric_only)
> > > > -               print_metric_headers(config, evlist, " ", true);
> > > > +               print_metric_headers(config, evlist, true);
> > > >  }
> > > >
> > > >  static void print_header(struct perf_stat_config *config,
> > > > --
> > > > 2.38.1.584.g0f3c55d4c2-goog
> > > >
  
Arnaldo Carvalho de Melo Dec. 5, 2022, 12:40 p.m. UTC | #6
Em Mon, Dec 05, 2022 at 09:22:07AM -0300, Arnaldo Carvalho de Melo escreveu:
> Em Tue, Nov 29, 2022 at 09:13:11PM -0800, Ian Rogers escreveu:
> > More specifically, I think os->prefix needs testing for NULL:
> > https://git.kernel.org/pub/scm/linux/kernel/git/acme/linux.git/tree/tools/perf/util/stat-display.c?h=perf/core#n356
> > so:
> > fputs(os->prefix, os->fh);
> > should be:
> > if (os->prefix)
> >   fputs(os->prefix, os->fh);
 
> Going thru the messages, for now I just added the test.

So I added this, as the patch introducing the problem was already in
acme/perf/core, please see if this is acceptable.

- Arnaldo

commit e21eb4d4fbd298a94ac200e2b6c3bea431e8cbca
Author: Ian Rogers <irogers@google.com>
Date:   Mon Dec 5 09:34:04 2022 -0300

    perf stat: Check existence of os->prefix, fixing a segfault
    
    We need to check if we have a OS prefix, otherwise we stumble on a
    metric segv that I'm now seeing in Arnaldo's tree:
    
      $ gdb --args perf stat -M Backend true
      ...
      Performance counter stats for 'true':
    
              4,712,355      TOPDOWN.SLOTS                    #     17.3 % tma_core_bound
    
      Program received signal SIGSEGV, Segmentation fault.
      __strlen_evex () at ../sysdeps/x86_64/multiarch/strlen-evex.S:77
      77      ../sysdeps/x86_64/multiarch/strlen-evex.S: No such file or directory.
      (gdb) bt
      #0  __strlen_evex () at ../sysdeps/x86_64/multiarch/strlen-evex.S:77
      #1  0x00007ffff74749a5 in __GI__IO_fputs (str=0x0, fp=0x7ffff75f5680 <_IO_2_1_stderr_>)
      #2  0x0000555555779f28 in do_new_line_std (config=0x555555e077c0 <stat_config>, os=0x7fffffffbf10) at util/stat-display.c:356
      #3  0x000055555577a081 in print_metric_std (config=0x555555e077c0 <stat_config>, ctx=0x7fffffffbf10, color=0x0, fmt=0x5555558b77b5 "%8.1f", unit=0x7fffffffbb10 "%  tma_memory_bound", val=13.165355724442199) at util/stat-display.c:380
      #4  0x00005555557768b6 in generic_metric (config=0x555555e077c0 <stat_config>, metric_expr=0x55555593d5b7 "((CYCLE_ACTIVITY.STALLS_MEM_ANY + EXE_ACTIVITY.BOUND_ON_STORES) / (CYCLE_ACTIVITY.STALLS_TOTAL + (EXE_ACTIVITY.1_PORTS_UTIL + tma_retiring * EXE_ACTIVITY.2_PORTS_UTIL) + EXE_ACTIVITY.BOUND_ON_STORES))"..., metric_events=0x555555f334e0, metric_refs=0x555555ec81d0, name=0x555555f32e80 "TOPDOWN.SLOTS", metric_name=0x555555f26c80 "tma_memory_bound", metric_unit=0x55555593d5b1 "100%", runtime=0, map_idx=0, out=0x7fffffffbd90, st=0x555555e9e620 <rt_stat>) at util/stat-shadow.c:934
      #5  0x0000555555778cac in perf_stat__print_shadow_stats (config=0x555555e077c0 <stat_config>, evsel=0x555555f289d0, avg=4712355, map_idx=0, out=0x7fffffffbd90, metric_events=0x555555e078e8 <stat_config+296>, st=0x555555e9e620 <rt_stat>) at util/stat-shadow.c:1329
      #6  0x000055555577b6a0 in printout (config=0x555555e077c0 <stat_config>, os=0x7fffffffbf10, uval=4712355, run=325322, ena=325322, noise=4712355, map_idx=0) at util/stat-display.c:741
      #7  0x000055555577bc74 in print_counter_aggrdata (config=0x555555e077c0 <stat_config>, counter=0x555555f289d0, s=0, os=0x7fffffffbf10) at util/stat-display.c:838
      #8  0x000055555577c1d8 in print_counter (config=0x555555e077c0 <stat_config>, counter=0x555555f289d0, os=0x7fffffffbf10) at util/stat-display.c:957
      #9  0x000055555577dba0 in evlist__print_counters (evlist=0x555555ec3610, config=0x555555e077c0 <stat_config>, _target=0x555555e01c80 <target>, ts=0x0, argc=1, argv=0x7fffffffe450) at util/stat-display.c:1413
      #10 0x00005555555fc821 in print_counters (ts=0x0, argc=1, argv=0x7fffffffe450) at builtin-stat.c:1040
      #11 0x000055555560091a in cmd_stat (argc=1, argv=0x7fffffffe450) at builtin-stat.c:2665
      #12 0x00005555556b1eea in run_builtin (p=0x555555e11f70 <commands+336>, argc=4, argv=0x7fffffffe450) at perf.c:322
      #13 0x00005555556b2181 in handle_internal_command (argc=4, argv=0x7fffffffe450) at perf.c:376
      #14 0x00005555556b22d7 in run_argv (argcp=0x7fffffffe27c, argv=0x7fffffffe270) at perf.c:420
      #15 0x00005555556b26ef in main (argc=4, argv=0x7fffffffe450) at perf.c:550
      (gdb)
    
    Fixes: f123b2d84ecec9a3 ("perf stat: Remove prefix argument in print_metric_headers()")
    Acked-by: Namhyung Kim <namhyung@kernel.org>
    Cc: Adrian Hunter <adrian.hunter@intel.com>
    Cc: Athira Jajeev <atrajeev@linux.vnet.ibm.com>
    Cc: Ingo Molnar <mingo@kernel.org>
    Cc: James Clark <james.clark@arm.com>
    Cc: Jiri Olsa <jolsa@kernel.org>
    Cc: Kan Liang <kan.liang@linux.intel.com>
    Cc: Namhyung Kim <namhyung@kernel.org>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Xing Zhengjun <zhengjun.xing@linux.intel.com>
    Link: http://lore.kernel.org/lkml/CAP-5=fUOjSM5HajU9TCD6prY39LbX4OQbkEbtKPPGRBPBN=_VQ@mail.gmail.com
    Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/stat-display.c b/tools/perf/util/stat-display.c
index f1ee4b052198690f..9b7772e6abf6538f 100644
--- a/tools/perf/util/stat-display.c
+++ b/tools/perf/util/stat-display.c
@@ -353,7 +353,8 @@ static void do_new_line_std(struct perf_stat_config *config,
 			    struct outstate *os)
 {
 	fputc('\n', os->fh);
-	fputs(os->prefix, os->fh);
+	if (os->prefix)
+		fputs(os->prefix, os->fh);
 	aggr_printout(config, os->evsel, os->id, os->nr);
 	if (config->aggr_mode == AGGR_NONE)
 		fprintf(os->fh, "        ");
  

Patch

diff --git a/tools/perf/util/stat-display.c b/tools/perf/util/stat-display.c
index 744b7a40f59a..deed6ccf072f 100644
--- a/tools/perf/util/stat-display.c
+++ b/tools/perf/util/stat-display.c
@@ -996,10 +996,9 @@  static void print_no_aggr_metric(struct perf_stat_config *config,
 }
 
 static void print_metric_headers_std(struct perf_stat_config *config,
-				     const char *prefix, bool no_indent)
+				     bool no_indent)
 {
-	if (prefix)
-		fprintf(config->output, "%s", prefix);
+	fputc(' ', config->output);
 
 	if (!no_indent) {
 		int len = aggr_header_lens[config->aggr_mode];
@@ -1012,11 +1011,8 @@  static void print_metric_headers_std(struct perf_stat_config *config,
 }
 
 static void print_metric_headers_csv(struct perf_stat_config *config,
-				     const char *prefix,
 				     bool no_indent __maybe_unused)
 {
-	if (prefix)
-		fprintf(config->output, "%s", prefix);
 	if (config->interval)
 		fputs("time,", config->output);
 	if (!config->iostat_run)
@@ -1024,7 +1020,6 @@  static void print_metric_headers_csv(struct perf_stat_config *config,
 }
 
 static void print_metric_headers_json(struct perf_stat_config *config,
-				      const char *prefix __maybe_unused,
 				      bool no_indent __maybe_unused)
 {
 	if (config->interval)
@@ -1032,8 +1027,7 @@  static void print_metric_headers_json(struct perf_stat_config *config,
 }
 
 static void print_metric_headers(struct perf_stat_config *config,
-				 struct evlist *evlist,
-				 const char *prefix, bool no_indent)
+				 struct evlist *evlist, bool no_indent)
 {
 	struct evsel *counter;
 	struct outstate os = {
@@ -1047,11 +1041,11 @@  static void print_metric_headers(struct perf_stat_config *config,
 	};
 
 	if (config->json_output)
-		print_metric_headers_json(config, prefix, no_indent);
+		print_metric_headers_json(config, no_indent);
 	else if (config->csv_output)
-		print_metric_headers_csv(config, prefix, no_indent);
+		print_metric_headers_csv(config, no_indent);
 	else
-		print_metric_headers_std(config, prefix, no_indent);
+		print_metric_headers_std(config, no_indent);
 
 	if (config->iostat_run)
 		iostat_print_header_prefix(config);
@@ -1132,7 +1126,7 @@  static void print_header_interval_std(struct perf_stat_config *config,
 	}
 
 	if (config->metric_only)
-		print_metric_headers(config, evlist, " ", true);
+		print_metric_headers(config, evlist, true);
 	else
 		fprintf(output, " %*s %*s events\n",
 			COUNTS_LEN, "counts", config->unit_width, "unit");
@@ -1168,7 +1162,7 @@  static void print_header_std(struct perf_stat_config *config,
 	fprintf(output, ":\n\n");
 
 	if (config->metric_only)
-		print_metric_headers(config, evlist, " ", false);
+		print_metric_headers(config, evlist, false);
 }
 
 static void print_header_csv(struct perf_stat_config *config,
@@ -1178,7 +1172,7 @@  static void print_header_csv(struct perf_stat_config *config,
 			     const char **argv __maybe_unused)
 {
 	if (config->metric_only)
-		print_metric_headers(config, evlist, " ", true);
+		print_metric_headers(config, evlist, true);
 }
 static void print_header_json(struct perf_stat_config *config,
 			      struct target *_target __maybe_unused,
@@ -1187,7 +1181,7 @@  static void print_header_json(struct perf_stat_config *config,
 			      const char **argv __maybe_unused)
 {
 	if (config->metric_only)
-		print_metric_headers(config, evlist, " ", true);
+		print_metric_headers(config, evlist, true);
 }
 
 static void print_header(struct perf_stat_config *config,