linux-kernel - Re: [PATCH v2] perf annotate: allow 's' on source code lines

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Date:   Tue, 29 Jun 2021 08:00:31 -0700
From:   Ian Rogers <irogers@...gle.com>
To:     Riccardo Mancini <rickyman7@...il.com>
Cc:     Arnaldo Carvalho de Melo <acme@...nel.org>,
        Namhyung Kim <namhyung@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...hat.com>, Martin Liska <mliska@...e.cz>,
        linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] perf annotate: allow 's' on source code lines

On Fri, Jun 25, 2021 at 8:53 AM Riccardo Mancini <rickyman7@...il.com> wrote:
>
> Hi Ian,
>
> On Thu, 2021-06-24 at 22:37 -0700, Ian Rogers wrote:
> > On Thu, Jun 24, 2021 at 3:37 PM Riccardo Mancini <rickyman7@...il.com> wrote:
> > >
> > > In perf annotate, when 's' is pressed on a line containing
> > > source code, it shows the message "Only available for assembly
> > > lines".
> > > This patch gets rid of the error, moving the cursr to the next
> > > available asm line (or the closest previous one if no asm line
> > > is found moving forwards), before hiding source code lines.
> > >
> > > Changes in v2:
> > >  - handle case of no asm line found in
> > >    annotate_browser__find_next_asm_line by returning NULL and
> > >    handling error in caller.
> > >
> > > Signed-off-by: Riccardo Mancini <rickyman7@...il.com>
> >
> > Acked-by: Ian Rogers <irogers@...gle.com>
> >
> > > ---
> > >  tools/perf/ui/browsers/annotate.c | 32 ++++++++++++++++++++++++++++---
> > >  1 file changed, 29 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/tools/perf/ui/browsers/annotate.c
> > > b/tools/perf/ui/browsers/annotate.c
> > > index ad0a70f0edaf..f5509a958e38 100644
> > > --- a/tools/perf/ui/browsers/annotate.c
> > > +++ b/tools/perf/ui/browsers/annotate.c
> > > @@ -343,6 +343,29 @@ static void annotate_browser__calc_percent(struct
> > > annotate_browser *browser,
> > >         browser->curr_hot = rb_last(&browser->entries);
> > >  }
> > >
> > > +static struct annotation_line *annotate_browser__find_next_asm_line(
> > > +                                       struct annotate_browser *browser,
> > > +                                       struct annotation_line *al)
> > > +{
> > > +       struct annotation_line *it = al;
> > > +
> > > +       /* find next asm line */
> > > +       list_for_each_entry_continue(it, browser->b.top, node) {
> > > +               if (it->idx_asm >= 0)
> > > +                       return it;
> > > +       }
> > > +
> > > +       /* no asm line found forwards, try backwards */
> > > +       it = al;
> > > +       list_for_each_entry_continue_reverse(it, browser->b.top, node) {
> > > +               if (it->idx_asm >= 0)
> > > +                       return it;
> > > +       }
> > > +
> > > +       /* There are no asm lines */
> > > +       return NULL;
> > > +}
> > > +
> > >  static bool annotate_browser__toggle_source(struct annotate_browser
> > > *browser)
> > >  {
> > >         struct annotation *notes = browser__annotation(&browser->b);
> > > @@ -363,9 +386,12 @@ static bool annotate_browser__toggle_source(struct
> > > annotate_browser *browser)
> > >                 browser->b.index = al->idx;
> > >         } else {
> > >                 if (al->idx_asm < 0) {
> > > -                       ui_helpline__puts("Only available for assembly
> > > lines.");
> > > -                       browser->b.seek(&browser->b, -offset, SEEK_CUR);
> > > -                       return false;
> > > +                       /* move cursor to next asm line */
> >
> > comment nit, perhaps prefer "closest" rather than "next" due to
> > searching backward.
>
> The backward search is just a fallback in case the forward one finds no asm
> line, which I believe is unlikely. Maybe it's also impossible, but I don't
> really know how those lines are generated, so I put a fallback in place.
> Furthermore, "closest" would imply that a previous asm line could be chosen over
> a subsequent one if closer, even if the latter is present.
>
> Thanks,
> Riccardo

Agreed, thanks for thinking about this.

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

> >
> > Thanks,
> > Ian
> >
> > > +                       al = annotate_browser__find_next_asm_line(browser,
> > > al);
> > > +                       if (!al) {
> > > +                               browser->b.seek(&browser->b, -offset,
> > > SEEK_CUR);
> > > +                               return false;
> > > +                       }
> > >                 }
> > >
> > >                 if (al->idx_asm < offset)
> > > --
> > > 2.31.1
> > >
>
>