Re: [PATCH 1/5] perf annotate: Split struct cycles_info

From: Namhyung Kim <namhyung@kernel.org>
To: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>, Ian Rogers <irogers@google.com>,
	Adrian Hunter <adrian.hunter@intel.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	linux-perf-users@vger.kernel.org,
	Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Subject: Re: [PATCH 1/5] perf annotate: Split struct cycles_info
Date: Mon, 6 Nov 2023 14:23:47 -0800	[thread overview]
Message-ID: <CAM9d7cgWUfDR9J6NLZBEs-DhXGR1YdaQYyOuANTRbhhUwp=8WQ@mail.gmail.com> (raw)
In-Reply-To: <ZUlEP9pP3JiSxDVc@kernel.org>

Hi Arnaldo,

On Mon, Nov 6, 2023 at 11:53 AM Arnaldo Carvalho de Melo
<acme@kernel.org> wrote:
>
> Em Mon, Nov 06, 2023 at 04:34:51PM -0300, Arnaldo Carvalho de Melo escreveu:
> > Em Fri, Nov 03, 2023 at 12:19:03PM -0700, Namhyung Kim escreveu:
> > > The cycles info is used only when branch stack is provided.  Split them
> > > into a separate struct and lazy allocate them to save some memory.
> > >
> > > Signed-off-by: Namhyung Kim <namhyung@kernel.org>
> > > ---
> > >  tools/perf/ui/browsers/annotate.c |  2 +-
> > >  tools/perf/util/annotate.c        | 34 ++++++++++++++++++-------------
> > >  tools/perf/util/annotate.h        | 14 ++++++++-----
> > >  3 files changed, 30 insertions(+), 20 deletions(-)
> > >
> > > diff --git a/tools/perf/ui/browsers/annotate.c b/tools/perf/ui/browsers/annotate.c
> > > index ccdb2cd11fbf..d2470f87344d 100644
> > > --- a/tools/perf/ui/browsers/annotate.c
> > > +++ b/tools/perf/ui/browsers/annotate.c
> > > @@ -337,7 +337,7 @@ static void annotate_browser__calc_percent(struct annotate_browser *browser,
> > >                             max_percent = percent;
> > >             }
> > >
> > > -           if (max_percent < 0.01 && pos->al.ipc == 0) {
> > > +           if (max_percent < 0.01 && (!pos->al.cycles || pos->al.cycles->ipc == 0)) {
> > >                     RB_CLEAR_NODE(&pos->al.rb_node);
> > >                     continue;
> > >             }
> > > diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c
> > > index 82956adf9963..3e7f75827270 100644
> > > --- a/tools/perf/util/annotate.c
> > > +++ b/tools/perf/util/annotate.c
> > > @@ -1100,8 +1100,8 @@ static void annotation__count_and_fill(struct annotation *notes, u64 start, u64
> > >             for (offset = start; offset <= end; offset++) {
> > >                     struct annotation_line *al = notes->offsets[offset];
> > >
> > > -                   if (al && al->ipc == 0.0) {
> > > -                           al->ipc = ipc;
> > > +                   if (al && al->cycles && al->cycles->ipc == 0.0) {
> > > +                           al->cycles->ipc = ipc;
> > >                             cover_insn++;
> > >                     }
> > >             }
> > > @@ -1134,13 +1134,18 @@ void annotation__compute_ipc(struct annotation *notes, size_t size)
> > >             if (ch && ch->cycles) {
> > >                     struct annotation_line *al;
> > >
> > > +                   al = notes->offsets[offset];
> > > +                   if (al && al->cycles == NULL) {
> > > +                           al->cycles = zalloc(sizeof(*al->cycles));
> > > +                           if (al->cycles == NULL)
> >
> > Shouldn't we stop here and tell the user that his system is really tight
> > on memory instead of just ignoring it?
> >
> >       if (al->cycles == NULL) {
> >               ui__error("Not enough memory for allocating branch stack cycles info!\n");
> >               return ... its a void function :-\
> >       }
> >
> > Since its a void function, can't we detect that we need al->cycles
> > allocated at the tool start and allocate it there, then propagate back
> > the error?
> >
> > Its per line, so doing it lazily is indeed easier, so make that function
> > return an error and bail out when not being able to calculate the ipc
> > for the remaining lines?
>
> I.e. with this folded into this patch, all but one of the callers of
> symbol__annotate2() already call a ui error messagem for instance:
>
>                 err = symbol__annotate2(ms, evsel, opts, &browser.arch);
>                 if (err) {
>                         char msg[BUFSIZ];
>                         dso->annotate_warned = true;
>                         symbol__strerror_disassemble(ms, err, msg, sizeof(msg));
>                         ui__error("Couldn't annotate %s:\n%s", sym->name, msg);
>
> - Arnaldo

Looks good to me, thanks for doing this!
Namhyung

>
> diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c
> index 3e7f758272703554..99ff3bb9cad8daa6 100644
> --- a/tools/perf/util/annotate.c
> +++ b/tools/perf/util/annotate.c
> @@ -1114,12 +1114,13 @@ static void annotation__count_and_fill(struct annotation *notes, u64 start, u64
>         }
>  }
>
> -void annotation__compute_ipc(struct annotation *notes, size_t size)
> +static int annotation__compute_ipc(struct annotation *notes, size_t size)
>  {
> +       int err = 0;
>         s64 offset;
>
>         if (!notes->src || !notes->src->cycles_hist)
> -               return;
> +               return 0;
>
>         notes->total_insn = annotation__count_insn(notes, 0, size - 1);
>         notes->hit_cycles = 0;
> @@ -1137,8 +1138,10 @@ void annotation__compute_ipc(struct annotation *notes, size_t size)
>                         al = notes->offsets[offset];
>                         if (al && al->cycles == NULL) {
>                                 al->cycles = zalloc(sizeof(*al->cycles));
> -                               if (al->cycles == NULL)
> -                                       continue;
> +                               if (al->cycles == NULL) {
> +                                       err = ENOMEM;
> +                                       break;
> +                               }
>                         }
>                         if (ch->have_start)
>                                 annotation__count_and_fill(notes, ch->start, offset, ch);
> @@ -1150,7 +1153,21 @@ void annotation__compute_ipc(struct annotation *notes, size_t size)
>                         notes->have_cycles = true;
>                 }
>         }
> +
> +       if (err) {
> +               while (++offset < (s64)size) {
> +                       struct cyc_hist *ch = &notes->src->cycles_hist[offset];
> +
> +                       if (ch && ch->cycles) {
> +                               struct annotation_line *al = notes->offsets[offset];
> +                               if (al)
> +                                       zfree(&al->cycles);
> +                       }
> +               }
> +       }
> +
>         annotation__unlock(notes);
> +       return 0;
>  }
>
>  int addr_map_symbol__inc_samples(struct addr_map_symbol *ams, struct perf_sample *sample,
> @@ -3270,7 +3287,11 @@ int symbol__annotate2(struct map_symbol *ms, struct evsel *evsel,
>
>         annotation__set_offsets(notes, size);
>         annotation__mark_jump_targets(notes, sym);
> -       annotation__compute_ipc(notes, size);
> +
> +       err = annotation__compute_ipc(notes, size);
> +       if (err)
> +               goto out_free_offsets;
> +
>         annotation__init_column_widths(notes, sym);
>         notes->nr_events = nr_pcnt;
>
> diff --git a/tools/perf/util/annotate.h b/tools/perf/util/annotate.h
> index 16d27952fd5c1b47..19bc2f03917575a8 100644
> --- a/tools/perf/util/annotate.h
> +++ b/tools/perf/util/annotate.h
> @@ -329,7 +329,6 @@ static inline bool annotation_line__filter(struct annotation_line *al, struct an
>  }
>
>  void annotation__set_offsets(struct annotation *notes, s64 size);
> -void annotation__compute_ipc(struct annotation *notes, size_t size);
>  void annotation__mark_jump_targets(struct annotation *notes, struct symbol *sym);
>  void annotation__update_column_widths(struct annotation *notes);
>  void annotation__init_column_widths(struct annotation *notes, struct symbol *sym);